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Internet Draft                                                F. Gennai
Intended status: Standards track                              A. Shahin
Expires: December 2009                                         ISTI-CNR
                                                            C. Petrucci
                                                         A. Vinciarelli
                                                                  CNIPA
                                                              June 2009




                        Certified Electronic Mail
                   draft-gennai-smime-cnipa-pec-03.txt




Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with
   the provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on December 2009.


Copyright Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.


Abstract

   Since 1997, the Italian Laws have recognized electronic delivery
   systems as legally usable. In 2005 after two years of technical


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   tests, the characteristics of an official electronic delivery
   service, named certified electronic mail (in Italian "Posta
   Elettronica Certificata") were defined, giving the system legal
   standing.

   Design of the entire system was carried out by the National Center
   for Informatics in the Public Administration of Italy (CNIPA),
   followed by efforts for the implementation and testing of the
   service. The CNIPA has given the Italian National Research Council
   (CNR), and in particular The Institute of Information Science and
   Technologies at the CNR (ISTI), the task of running tests on
   providers of the service to guarantee the correct implementation and
   interoperability. This document describes the certified email system
   adopted in Italy. It represents the system as it is at the moment of
   writing, following the technical regulations that were written based
   upon the Italian Law DPR. November 2, 2005.


Table of Contents

   1. Introduction .................................................. 3
      1.1. Scope .................................................... 4
      1.2. Notational Conventions ................................... 4
           1.2.1. Requirement Conventions ........................... 4
           1.2.2. Acronyms .......................................... 5
           1.2.3. Terminology and Definitions ....................... 5
   2. PEC model ..................................................... 9
      2.1. System-generated messages ................................ 9
           2.1.1. Message types .................................... 11
      2.2. Basic structure ......................................... 13
           2.2.1. Access point ..................................... 13
           2.2.2. Incoming point ................................... 15
           2.2.3. Delivery point ................................... 18
           2.2.4. Storage .......................................... 18
           2.2.5. Provider service mailbox ......................... 19
      2.3. Log ..................................................... 19
   3. Message processing ........................................... 20
      3.1. Access point ............................................ 20
           3.1.1. Formal checks on messages ........................ 20
           3.1.2. Non-acceptance notification due to one or more
                  formal exceptions................................. 20
           3.1.3. Non-acceptance notification due to virus detection 21
           3.1.4. Acceptance notification .......................... 22
           3.1.5. Transport envelope ............................... 23
           3.1.6. Timeout delivery error notification .............. 24
      3.2. Incoming point .......................................... 26
           3.2.1. Take in charge notification ...................... 26
           3.2.2. Anomaly envelope ................................. 27



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           3.2.3. Virus detection notification ..................... 29
           3.2.4. Virus-induced delivery error notification ........ 30
      3.3. Delivery point .......................................... 30
           3.3.1. Checks on incoming messages ...................... 30
           3.3.2. Delivery notification ............................ 31
           3.3.3. Non-delivery notification ........................ 35
      3.4. Sender and receiver belonging to the same domain ........ 36
      3.5. Example: Complete transaction between 2 PEC domains ..... 36
   4. Formats ...................................................... 37
      4.1. Temporal reference ...................................... 37
      4.2. User date/time .......................................... 37
      4.3. Attachments ............................................. 37
           4.3.1. Message body ..................................... 38
           4.3.2. Original message ................................. 38
           4.3.3. Certification data ............................... 38
      4.4. Certification data scheme ............................... 38
      4.5. PEC providers directory scheme .......................... 41
   5. Security-related aspects ..................................... 48
      5.1. Digital signature ....................................... 48
      5.2. Authentication .......................................... 48
      5.3. Secure interaction ...................................... 49
      5.4. Virus ................................................... 50
      5.5. S/MIME certificate ...................................... 50
           5.5.1. Provider-related information (subject) ........... 50
           5.5.2. Certificate extensions ........................... 50
           5.5.3. Example .......................................... 51
      5.6. PEC providers directory ................................. 56
   6. PEC system client technical and functional prerequisites ..... 56
   7. Security Considerations ...................................... 56
   8. IANA Considerations .......................................... 57
   9. References ................................................... 57
      9.1. Normative References .................................... 57
   10. Acknowledgments ............................................. 58
   APPENDIX A: Italian fields and values in English ................ 59
   Authors' Addresses .............................................. 60


1. Introduction

   Since 1997, the Italian Laws have recognized electronic delivery
   systems as legally usable. In 2005 after two years of technical
   tests, the characteristics of an official electronic delivery
   service, named certified electronic mail (in Italian Posta
   Elettronica Certificata, from now on "PEC") were defined, giving
   the system legal standing.





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1.1. Scope

   To ensure secure transactions over the Internet, cryptography can
   be associated with electronic messages in order to provide some
   guarantee on sender identity, message integrity, confidentiality,
   and non-repudiation of origin. Many end-to-end techniques exist to
   accomplish such goals, and some offer a high level of security. The
   downside of end-to-end cryptography is the need for an extensive
   penetration of technology in society, because it is essential for
   every user to have asymmetric keys and certificates signed by a
   Certification Authority. Along with that, users would need to have
   an adequate amount of knowledge regarding the use of such
   technology.

   PEC on the other hand uses applications running on servers to
   digitally sign messages, thus avoiding the complexity end-to-end
   systems bring about. By doing so, the user needs only have an
   ordinary mail client with which to interact. The downside is that
   the level of security drops, since the protection does not cover the
   entire transaction. Nonetheless, application is simpler and does not
   require specific user skills, making it easily more widespread among
   users.

   A provider for such a service MUST follow certain regulations and
   undergo several tests of compatibility and interoperability before
   it can be considered legally functional.

   This document describes PEC's technical aspects and features. It
   presents the details of the protocol and the messages that are sent
   between service providers. It is meant to introduce the system
   adopted by the Italian government for the exchange of certified
   emails, giving them a legal standing equivalent to that of
   Registered Mail with Return Receipt.


1.2. Notational Conventions

1.2.1. Requirement Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [REQ].








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1.2.2. Acronyms

   CMS:      Cryptographic Message Syntax
   CNIPA:    Italian National Agency for Digital Administration
             (Centro Nazionale per l'Informatica nella Pubblica
             Amministrazione)
   CNR:      Italian National Research Council (Consiglio Nazionale
             delle Ricerche)
   CRL:      Certificate Revocation List
   CRL DP:   Certificate Revocation List Distribution Point
   DNS:      Domain Name Service
   DTD:      Document Type Definition
   FQDN:     Fully Qualified Domain Name
   ISTI:     The Institute of Information Science and Technologies
             at the CNR (Istituto di Scienza e Tecnologie
             dell'Informazione "A.Faedo")
   LDAP:     Lightweight Directory Access Protocol
   LDIF:     LDAP Data Interchange Format
   MIME:     Multipurpose Internet Mail Extensions
   PEC:      Certified Electronic Mail (Posta Elettronica Certificata)
   S/MIME:   Secure/MIME
   SMTP:     Simple Mail Transfer Protocol
   TLS:      Transport Layer Security
   XML:      eXtensible Markup Language


1.2.3. Terminology and Definitions

   Acceptance notification: Emitted by the sending access point to its
   user upon the latter's request to send a PEC message. This occurs
   when checks on said message pass, and serves to notify the user that
   the provider will be taking care of sending the PEC message to its
   intended destination(s). It contains certification data and is
   signed using the sender PEC provider's key.

   Access point: Is what interfaces the user to the rest of the PEC
   system. It provides access services for user identification, as well
   as sending and reading PEC messages. An access point also performs
   virus checks (on outgoing messages), and inserts the original
   message into a transport envelope. The messages it can emit are:

   o acceptance notifications.

   o non-acceptance notifications, either due to some formal exception
     or virus presence.





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   Anomaly envelope: When a message contains errors or is not a PEC
   message it is inserted inside an anomaly envelope to highlight the
   irregularity to the receiving user. The envelope is signed using the
   receiver PEC provider's key.

   Brief delivery notification: A type of delivery notification that
   contains the original message, certification data, and hash values
   of the attachments that were included in the original message, if
   any.

   Certification data: A set of data, certified by the sender's PEC
   provider, that describes the original message. This data is inserted
   in notifications and is transferred to the recipient, along with the
   original message, inside a transport envelope.
   Certification data includes: date and time of dispatch, sender email
   address, recipient(s) email address(es), subject, and message ID.

   Certified electronic mail: A service based on electronic mail, as
   defined by the [SMTP] standard and its extensions, which permits the
   transmission of documents produced with informatics tools.

   Complete delivery notification: A type of notification that contains
   delivery confirmation text and certification data, as well as the
   entire original message.

   Concise delivery notification: A type of notification that contains
   delivery confirmation text and certification data only attached to
   it.

   Delivery point: Is the point that delivers PEC messages to the
   intended recipient's PEC mailbox. It also runs checks on the source
   and correctness of the message. The messages it can emit are:

   o delivery notification.

   o non-delivery notification.

   All messages received by the delivery point are stored in the
   recipient's mailbox.

   Delivery notification: Emitted by the receiver delivery point to the
   sender incoming point, which then forwards it to the sender delivery
   point, upon insertion of the message inside the recipient's PEC
   mailbox. A separate delivery notification is generated upon delivery
   of the message to each different recipient indicated in the "To:"
   and "Cc:" fields of said message. The notification is signed using
   the receiver PEC provider's key.




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   Holder: The person or organization to whom a PEC mailbox is
   assigned.

   Incoming point: Is the point that receives messages within a PEC
   domain. Once received, it runs checks on origin and correctness,
   inserts messages that contain errors in anomaly envelopes, checks
   for the presence of viruses in incoming messages, and, when all
   checks pass, forwards the received message to the delivery point
   inside the same domain. The messages it can emit are:

   o take in charge notifications (inter-provider acknowledgment);

   o virus detection notifications;

   o non-delivery notifications due to timeout;

   o non-delivery notifications due to virus detection.

   All messages received by the incoming point are forwarded to the
   delivery point of the same domain.

   Message sent: A PEC message is considered sent when the sender's PEC
   provider, after several checks, accepts the email and returns an
   acceptance notification to the sender.

   Message received: A PEC message is considered received when it is
   stored in the receiver's mailbox, after which the receiver PEC
   provider returns a delivery notification to the sender.

   Msgid: Is the message ID generated by the email client, as defined
   in [EMAIL], before the message is submitted to the PEC system.

   Non-acceptance notification: Emitted by the sender access point to
   its user when it is impossible for it to accept the message. The
   reason (either virus or formal exceptions detection) is indicated
   within the notification text, which also explicitly informs the user
   that the message will not be forwarded to the receiver. The
   notification is signed using the sender PEC provider's key.

   Non-delivery notification: Emitted by the PEC provider to the sender
   of the original message, when message delivery is not possible, to
   indicate the anomaly. Non-delivery can be caused by one of the
   following 3 reasons:






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   o timeout; notification is generated by the sender incoming point
     and sent to the sender delivery point.

   o virus detection; notification is generated by the receiver
     incoming point and sent to the sender incoming point.

   o other reasons; such as disk quota exceeded, domain unknown or user
     unknown. In this case, the notification is generated by the
     receiver delivery point to the sender incoming point.

   Original message: Is the user-generated message before its arrival
   to the sender access point. The original message is delivered to the
   recipient inside a transport envelope.

   PEC domain: Corresponds to a DNS domain dedicated to the holders'
   mailboxes.

   PEC mailbox: An electronic mailbox for which delivery notifications
   are issued upon reception of PEC messages. Such a mailbox can be
   defined exclusively within a PEC domain.

   PEC msgid: Is a unique identifier generated by the PEC system, which
   will substitute the msgid.

   PEC provider: The entity that handles one or more PEC domains with
   their relative points of access, reception, and delivery. It is the
   holder of the key that is used for signing notifications and
   envelope, and it interacts with other PEC providers for
   interoperability with other holders.

   PEC provider's key: Is a key released by CNIPA to every PEC
   provider. It is used to sign notifications and envelopes, and to
   authorize access to the PEC providers directory.

   PEC providers directory: Is an LDAP server positioned in an area
   reachable by all PEC service providers. It constitutes the technical
   structure related to the public list of PEC service providers, and
   contains the list of PEC domains and service providers with relevant
   certificates corresponding to the keys used for signing
   notifications and transport envelopes.

   Service mailbox: A mailbox for the sole use of the provider,
   dedicated for the reception of take in charge and virus detection
   notifications.





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   Take in charge notification: Emitted by the receiver incoming point
   to the sender's service mailbox -through the latter's incoming
   point- to attest that the receiver PEC provider has taken
   responsibility for message delivery. Certification data is inserted
   within this notification to allow its association with the message
   it refers to. It is then signed using the receiving PEC provider's
   key.

   Time stamp: A digital evidence with which a temporal reference, that
   can be opposed by third parties, is attributed to one or more
   documents.

   Transport envelope: A message created by the sender access point, in
   which the original message and related certification data are
   inserted. It is signed using the sender PEC provider's key, and is
   delivered, unmodified, to the receiving PEC mailbox. Thus, allowing
   the verification of the certification data by the receiving user.

2. PEC model

2.1. System-generated messages

   The PEC system generates messages in MIME format. They are composed
   of a descriptive textual part and some other MIME parts, the number
   and content of which varies according to the type of message
   generated.

   A system-generated message falls into one of the following
   categories:

   o Notifications;

   o Envelopes.

   The message is inserted in an S/MIME v3 structure in CMS format
   and signed with the PEC provider's private key. The X.509v3
   certificate associated with the key MUST be included in the
   aforementioned structure. The S/MIME format used to sign system-
   generated messages is the "multipart/signed" format (.p7s), as
   described in section 3.4.3 of [SMIMEV3].

   To guarantee the verifiability of signatures on as many mail clients
   as possible, X.509v3 certificates used by certified email systems
   MUST abide by the profile found in section 6.5.






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   In order for the receiving mail client to verify the signature,
   the sender address MUST coincide with the one indicated within the
   X.509v3 certificate. For this mechanism, transport envelopes MUST
   indicate in the "From:" field a sender address which is different
   from the one contained in the original message. To allow for better
   message usability by the receiving user, the sender's mail address
   in the original message is inserted as a "display name".
   For example, a "From:" field such as:

         From: "John Smith" <john.smith@domain.com>

   would result in the following "From:" value in the respective
   transport envelope:

         From: "On behalf of: john.smith@domain.com"
                                     <certified-mail@provider.com>

   In order for replies to be correctly sent back to the proper
   destination, the "Reply-To:" field in the transport envelope MUST
   contain the same unaltered value of the original message's
   "Reply-To:" field. When it is not explicitly specified in the
   original message, the system that generates the transport envelope
   creates it by extracting the information from the "From:" field in
   the original message.

   When notifications are sent, the system MUST use the original
   message sender's address as the destination address, as is specified
   in the reverse path data of the SMTP protocol.
   Notifications MUST be sent to the sender's PEC mailbox without
   taking into account the "Reply-To:" field, which might be present
   in the original message's header.

   All system-generated PEC messages are identifiable for having a
   specific header defined in PEC according to the type of message
   generated.

   To determine the certification data, the elements used for the
   actual routing of the message are employed. In SMTP dialog phases,
   the reverse path and forward path data ("MAIL FROM" and "RCPT TO"
   commands) are thus considered certification data of both the sender
   and the recipients respectively. Addressing data present in the
   message body ("To:" and "Cc:" fields) are used solely in order to
   discriminate between primary and carbon copy recipients when
   necessary; addressing data present in the "Bcc:" field MUST be
   considered invalid by the system.





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2.1.1. Message types

   All system-generated messages inherit their header fields and values
   from the original message, with extra fields added according to the
   type of message generated.

2.1.1.1. Notifications

   They have the purpose of informing the sending user and interacting
   providers of the progress the message is making within the PEC
   network.

2.1.1.1.1. Success notifications

   Indicates an acknowledgment on the provider's side for the reception
   or handling of a PEC message. More specifically, it can indicate one
   of 3 situations: acceptance, take in charge, or delivery.

   Added header fields are:

   o X-Ricevuta

   o X-Riferimento-Message-ID

   The field "X-Ricevuta" (Notification) indicates the type of
   notification contained in the message, whereas "X-Riferimento-
   Message-ID" (Reference Message-ID) contains the message ID generated
   by the mail client.

   The body contents differ according to the notification type. This is
   described more thoroughly in chapter 3.

   o An acceptance notification informs the user that his provider has
     accepted the message and will be taking care of passing it on to
     the provider(s) of the addressee(s).

   o A take in charge notification is an inter-provider communication
     only, it MUST NOT be sent to the users. With this notification,
     the receiving provider simply informs the sending one that it has
     received a PEC message, and will take the responsibility of
     forwarding it to the addressee(s). From then on, the sender
     provider is no longer held responsible as to the whereabouts of
     the message, but is limited to notifying its user of the success
     or failure of delivery.






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   o Delivery notifications take place as the final communication of a
     transaction, indicating overall success in handing the message
     over to the addressee(s).

2.1.1.1.2. Delay notifications

   Delay notifications are sent out 12 hours after a message has been
   dispatched from the sending provider, and no take in charge or
   delivery notification was received. These have the sole purpose of
   notifying the user of the delay.

   If another 12 hours go by without any sign of a take in charge or
   delivery notification (amounting to a 24-hour delay), another delay
   notification is dispatched to the user informing him of the possible
   delivery failure. The provider will not keep track of the delay any
   further.

2.1.1.1.3. Failure notifications

   They are sent when there is some error in transmission or reception.
   More specifically, a failure notification can indicate either a
   formal-exception error, or a virus detection.

   Added header fields are:

   o X-Ricevuta;

   o X-Riferimento-Message-ID;

   o X-VerificaSicurezza [optional]

   "X-Ricevuta" (Notification) and "X-Riferimento-Message-ID"
   (Reference Message-ID) have the same roles as indicated in section
   2.1.1.1.1 (Success Notifications). "X-VerificaSicurezza" (Security
   Verification) is an optional header field, used for virus-related
   notifications.

   Body contents differ according to notification type. This is
   described more thoroughly in chapter 3.

2.1.1.2. PEC envelopes

   Messages entering the PEC network are inserted within specific PEC
   messages, called envelopes, before they are allowed to circulate
   further within the network. These envelopes MUST inherit the
   following header fields, along with their unmodified values, from
   the message itself.



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   o Received

   o To

   o Cc

   o Return-Path

   o Reply-to (if present)

   Depending on the type of message requesting admission into the PEC
   network, it will be inserted either in a "Transport Envelope", or in
   a "Anomaly Envelope". Distinction will be possible through the
   addition of the "X-Transport" header field.

2.2. Basic structure

             +-------------+               +------------+
             |    +--+     |               |            |
             |    |AP|     |               |            |
   +----+    |    +--+     |   messages&   | +---+ +--+ |    +----+
   |user|<-->|             |<------------->| |InP| |DP| |<-->|user|
   +----+    | +--+  +---+ | notifications | +---+ +--+ |    +----+
             | |DP|  |InP| |               |            |
             | +--+  +---+ |               |            |
             +-------------+               +------------+
                  PEC                            PEC
                 sender                        receiver
                provider                       provider

   where:

   AP = Access Point
   DP = Delivery Point
   InP = Incoming Point

2.2.1. Access point

   This is what the user client at the sender side interacts with,
   giving the user access to PEC services set up by the provider.
   Such access MUST be preceded by user authentication on the system
   (see section 6.2). The access point receives the original messages
   its user wishes to send, runs some formal checks, and acts according
   to the outcome:






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   o if the message passes all checks, the access point generates an
     acceptance notification and inserts the original message inside a
     transport envelope;

   o if a formal exception is detected, the access point refuses the
     message and emits the relevant non-acceptance notification (see
     section 3.1.1);

   o if a virus is detected, the access point generates a non-
     acceptance notification and inserts the original message as is in
     the provider's special store.

   Generation of the acceptance notification indicates to the user that
   the message was accepted by the system, certifying also the date and
   time of the event. The notification MUST contain user-readable text,
   and an XML part containing the certification data.
   The notification MAY also contain other attachments for extra
   features offered by the provider.

   Using the data available in the PEC providers directory (see section
   4.5), the access point runs checks on every recipient in the "To:"
   and "Cc:" fields present in the original message to verify whether
   they belong to the PEC infrastructure or to non-PEC domains. Such
   checks are done by verifying the existence, through a case
   insensitive search, of the recipients' domains in the
   "managedDomains" attribute found within the PEC providers directory.
   Therefore, the acceptance notification (and relevant certification
   data) relates, for each address, the typology of its domain; PEC or
   non-PEC.

   The identifier (from now on PEC msgid) of accepted original messages
   within the PEC infrastructure MUST be unambiguous in order to
   consent correct tracking of messages and relative notifications. The
   format of such an identifier is:

        [alphanumeric string]@[provider mail domain]

   or:

        [alphanumeric string]@[FQDN mail server]

   Therefore, both the original message and the corresponding transport
   envelope MUST contain the following header field:

        Message-ID: <[unique identifier]>





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   When an email client that is interacting with the access point has
   already inserted a Message ID (from now on msgid) in the original
   message, that msgid SHALL be substituted by a PEC msgid. In order to
   allow the sender to link the message sent with the relative
   notifications, the msgid MUST be inserted in the original message as
   well as the relative notifications and transport envelope. If
   present, the msgid is REQUIRED in the original message's header by
   adding the following header field:

        X-Riferimento-Message-ID: <[original Message ID]>

   which will also be inserted in the transport envelope and
   notifications, and related in the certification data (see section
   4.4).

2.2.2. Incoming point

   This point permits the exchange of PEC messages and notifications
   between PEC providers. It is also the point through which ordinary
   mail messages can be inserted within the system of certified mail.

   The exchange of messages between providers takes place through
   SMTP-based transactions, as defined in [SMTP]. If SMTP communication
   errors occur, they MAY be handled using the standard error
   notification mechanisms, as provided by SMTP in [SMTP] and
   [SMTP-DSN]. The same mechanism is also adopted for handling
   transitory errors, that result in long idling periods, during an
   SMTP transmission phase. In order to guarantee that an error is
   returned to the user as defined in section 3.3.3, the systems that
   handles PEC traffic MUST adopt a time limit for message idleness
   equal to 24 hours.

   Once a message arrives, the incoming point runs the following list
   of checks and operations:

   o verifies correctness and type of the incoming message;

   o if the incoming message is a correct and undamaged transport
     message:

     - emits a take in charge notification towards the sender provider
       (section 3.2.1);

     - forwards the transport envelope to the delivery point (section
       3.3).





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   o if the incoming message is a correct and undamaged notification:

     - forwards the notification to the delivery point.

   o if the incoming message does not conform to the prerequisites of a
     correct and undamaged transport envelope or notification, but
     comes from a PEC provider, i.e. passes the verifications regarding
     existence, origin, and validity of the signature, then the message
     MUST be propagated towards the recipient.
     Therefore, the incoming point:

     - inserts the incoming message in an anomaly envelope (section
       3.2.2);

     - forwards the anomaly envelope to the delivery point.

   o if the incoming message does not originate from a PEC system, i.e.
     fails verifications regarding existence, origin, and validity of
     the signature, then the message will be treated as ordinary email,
     and, if propagated to the recipient:

     - is inserted in an anomaly envelope (section 3.2.2);

     - the anomaly envelope is forwarded to the delivery point.

   The take in charge notification is generated by the receiving
   provider and sent to the sending provider. Its purpose is to keep
   track of the message in its transition from one provider to another,
   and is therefore strictly intra-provider communication; the end user
   knows nothing about it.

   To check the correctness and integrity of a transport envelope or
   notification, the incoming point runs the following tests:

   o Signature existence - the system verifies the presence of an
     S/MIME signature structure within the incoming message;

   o Signature origin - the system verifies whether or not the
     signature belongs to a PEC provider by extracting the certificate
     used for signing and verifying its presence in the PEC providers
     directory. To ease the check, it is possible to calculate the
     certificate's SHA1 hash value and perform a case-insensitive
     search of its hexadecimal representation within the
     "providerCertificateHash" attribute found in the PEC providers
     directory. This operation allows to easily identify the sender





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   provider for subsequent and necessary matching checks between the
   extracted certificate and the one present in the provider's record;

   o Signature validity - S/MIME signature correctness is verified by
     recalculating the signature value, checking the entire
     certification path, and verifying the CRL and temporal validity of
     the certificate. In case some caching mechanism is used for CRL
     contents, an update interval MUST be adopted so that the most up-
     to-date data is guaranteed, thus minimizing the possible delay
     between a publication revocation by the Certification Authority
     and the variation acknowledgment by the provider;

   o Formal correctness - the provider performs sufficient and
     necessary checks to guarantee that the incoming message is
     compliant with the formats specified in this document (transport
     envelope and notifications).

   If a virus-infected transport envelope passes the checks just
   mentioned it is still considered correct and undamaged. The presence
   of the virus will be detected in a second phase, during which the
   contents of the transport envelope are verified. Thus, the incoming
   point will refrain from forwarding the message to the recipient,
   instead sending the appropriate notification of non-delivery and
   storing the virus-infected message in the provider's special
   storage.

   In case ordinary mail messages are received, the PEC provider SHALL
   perform virus checks in order to prevent the infiltration of
   potentially dangerous mail messages within the PEC system. If a
   virus is detected in an ordinary mail message, the latter can be
   discarded at the incoming point before it enters the PEC system.
   In other words, no special treatment is reserved for the error, but
   a handling that is conformant to the procedures usually followed for
   messages going through the Internet.

   When a virus is detected inside a transport envelope during the
   reception phase, the receiver's provider emits a virus detection
   notification to the sender provider. The sender provider then MUST:

   o check what virus typologies were not detected by its own
     antivirus, to understand the motivations and verify the
     possibility of interventions;

   o send a virus-induced non-delivery notification to the sender.






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2.2.3. Delivery point

   Is the point that receives messages from the incoming point and
   forwards them to the final recipient.

   It MUST run a series of tests on received messages before forwarding
   them to the user (see section 3.3.1). It first verifies the typology
   of the message, and decides whether or not a notification should be
   issued to the sender. The delivery notification (section 3.3.2) is
   emitted after the message was delivered to the recipient's PEC
   mailbox and only at reception of a valid transport envelope, which
   can be identifiable by the presence of the header attribute:

        X-Trasporto: posta-certificata

   In all other cases, such as anomaly envelopes and notifications,
   the delivery notification is not emitted. Regardless, the message
   received from the delivery point MUST be delivered unmodified to
   the recipient's mailbox.

   The delivery notification indicates to the sender that the message
   sent was in fact conveyed to the specified recipient's mailbox, and
   certifies the date and time of delivery through use of user-readable
   text and an XML part containing certification data, along with other
   possible attachments added for extra features offered by the
   provider.

   If the message received at the delivery point can't be delivered
   to the destination mailbox, the delivery point emits a non-delivery
   notification (section 3.3.3). This notification is generated when an
   error relative to the delivery of a correct transport envelope is
   encountered.

2.2.4. Storage

   Each provider MUST dedicate a special storage for the deposition
   of any virus-infected messages encountered. Whether the virus be
   detected by the sender's access point or the receiver's incoming
   point, the provider that detects it MUST store the mail message in
   its own storage, and keep it for 30 months.










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2.2.5. Provider service mailbox

   For exclusive use of the provider, dedicated to the reception of
   notifications in 2 cases only:

   o take in charge notifications; and

   o virus detection notification.

2.3. Log

   The server administrator MUST keep track of any and all operations
   carried out in a specific message log file. The information kept in
   the log for each operation is the following:

   o message ID (the value present in the Message-ID header field in
     the original message)

   o date and time of event

   o sender of original message

   o recipient(s) of original message

   o subject of original message

   o event type (reception, delivery, notification emission, etc)

   o Message-IDs of related generated messages

   o sending provider

   The service provider MUST store this data and preserve it
   unmodified. Italian laws have specified that the service provider
   retain the data for 30 months.















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3. Message processing

3.1. Access point

3.1.1. Formal checks on messages

   When the access point receives a message the user wishes to send, it
   MUST guarantee said message's formal conformity, verifying that the:

   o message body contains a "From:" field holding a [EMAIL]-compliant
     email address;

   o message body contains a "To:" field holding one or more [EMAIL]-
     compliant email addresses;

   o sender's address, specified in the SMTP reverse path, coincides
     with the one in the message's "From:" field;

   o recipients' addresses specified in the SMTP forward path coincide
     with the ones present in the "To:" or "Cc:" fields of the message;

   o "Bcc:" field does not hold any value;

   o total message size falls within the limits accepted by the
     provider. Such limits apply depending on the number of recipients
     as well; by multiplying it to the message size, the outcome MUST
     fall within the limits accepted by the provider. Italian Laws have
     specified this limit as being 30MB.

   If the message does not pass the tests, the access point MUST NOT
   accept the message within the PEC system, thus emitting the relative
   notification of non-acceptance.

3.1.2. Non-acceptance notification due to one or more formal exceptions

   When the access point cannot forward the message received, due to
   failure in passing the formal checks, the sender is notified of such
   an outcome. If the error is caused by the message failing size
   checks, a non-acceptance notification is sent as long as the size
   remains bound by a certain limit. If the size exceeds said limit,
   error handling is left to SMTP.

   The header for such a notification will contain the following
   fields:






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        X-Ricevuta: non-accettazione
        Date: [date of notification emission]
        Subject: AVVISO DI NON ACCETTAZIONE: [original subject]
        From: certified-mail@[mail domain]
        To: [original sender]
        X-Riferimento-Message-ID: [Message-ID of original message]

   The body of this notification is composed of text that
   constitutes the actual notification in readable format according
   to a model that relates the following information:

        Error in message acceptance
        On [date] at [time] ([time zone]), in the message "[subject]"
        originating from "[original sender]" and addressed to:
        [recipient_1]
        [recipient_2]
        .
        .
        .
        [recipient_n]
        a problem was detected which prevents its acceptance due to
        [error description].
        The message was not accepted.
        Message identification: [Message-ID]

   The same certification information is inserted within an XML file
   to be attached to the notification message, allowing automatic
   checks on the message (section 4.4). The non-acceptance notification
   MAY contain additional attachments included by the provider for
   provider-specific services, regardless the original message MUST NOT
   be attached.

3.1.3. Non-acceptance notification due to virus detection

   If the access point receives virus-infected emails from its user,
   it MUST NOT accept them, but notify the sender immediately of
   dispatch impossibility instead.

   The access point MUST run some tests on the content of the incoming
   message and reject it if a virus is detected. In which case, a
   virus-detection-induced non-acceptance notification MUST be emitted
   to clearly communicate the reason of message refusal to the user.

   For this non-acceptance notification the header contains the
   following fields:





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        X-Ricevuta: non-accettazione
        X-VerificaSicurezza: errore
        Date: [notification emission date]
        Subject: AVVISO DI NON ACCETTAZIONE PER VIRUS: [original
                 subject]
        From: certified-mail@[mail_domain]
        To: [original sender]
        X-Riferimento-Message-ID: [Message-ID of original message]

   The notification's body is composed of readable text according to
   the following model:

        Error in message acceptance due to virus presence
        On [date] at [time] ([time zone]), in the message "[subject]"
        originating from "[original sender]" and addressed to:
        [recipient_1]
        [recipient_2]
        .
        .
        .
        [recipient_n]
        a security problem was detected [ID of detected content type].
        The message was not accepted.
        Message identification: [Message-ID]

   The same certification data is inserted in an XML file added to the
   notification to allow for automatic checks (section 4.4). The non-
   acceptance notification MAY contain additional attachments included
   by the provider for provider-specific services, regardless the
   original message MUST NOT be attached.

3.1.4. Acceptance notification

   The acceptance notification is a message sent to the sender,
   containing date and time of acceptance, sender and recipient data,
   and subject.

   The header will contain the following fields:

        X-Ricevuta: accettazione
        Date: [actual date of acceptance]
        Subject: ACCETTAZIONE: [original subject]
        From: certified-mail@[mail_domain]
        To: [original sender]
        X-Riferimento-Message-ID: [Message-ID of original message]





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   The message body is composed of text that constitutes the
   notification in readable format, according to a model that relates
   the following information:

        Acceptance notification
        On [date] at [time] ([time zone]), the message "[subject]"
         originating from "[original sender]" and addressed to:
        [recipient_1] (["certified mail" | "ordinary mail"])
        [recipient_2] (["certified mail" | "ordinary mail"])
        .
        .
        .
        [recipient_n] (["certified mail" | "ordinary mail"])
        was accepted by the system and forwarded to the recipient(s).
        Message identification: [Message-ID]

   The same certification information is inserted within an XML file
   attached to the notification message, allowing automatic checks
   on it (section 4.4). The acceptance notification MAY contain
   additional attachments included by the provider for provider-
   specific services.

3.1.5. Transport envelope

   A transport envelope is a message generated by the access point
   which contains the original message as well as certification data.

   As was mentioned in section 2.1.1.2, the transport envelope inherits
   from the original message the values of the following header fields,
   which MUST be related unmodified:

   o Received

   o To

   o Cc

   o Return-Path

   o Reply-To (if present)

   On the other hand, the following fields MUST be modified, or
   inserted if necessary:

        X-Trasporto: posta-certificata
        Date: [actual date of acceptance]




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        Subject: POSTA CERTIFICATA: [original subject]
        From: "On behalf of: [original sender]"
                             <certified-mail@[mail_domain]>
        Reply-To: [original sender] (inserted only if not already
                  present)
        Message-ID: [PEC message ID generated as explained in 2.2.1]
        X-Riferimento-Message-ID: [message ID of original message]
        X-TipoRicevuta: [completa/breve/sintetica]

   The "X-TipoRicevuta" field indicates the type of delivery
   notification the sender wishes to receive - complete, brief, or
   concise.

   The body of the transport envelope is composed of text that
   constitutes the readable format of the message, according to a
   model that relates the following certification data:

        Certified mail message
        On [date] at [time] ([time zone]), the message "[subject]" was
        sent by "[original sender]" and addressed to:
        [recipient_1]
        [recipient_2]
        .
        .
        .
        [recipient_n]
        The original message is included in attachment.
        Message identification: [Message-ID]

   Within the transport envelope, the entire, non-modified original
   message is attached in a [EMAIL]-compliant format (except for what
   has been said regarding the Message ID). In the same transport
   envelope, another part is added, which is an XML part. It is easy to
   perform checks on, and contains the certification data that was
   already related in text format, as well as other information on the
   type of message and type of notification requested (section 4.4).
   The transport envelope MAY contain additional attachments included
   by the provider for provider-specific services.

   Note that the routing data of the transport envelope (forward and
   reverse paths) remain unaltered.

3.1.6. Timeout delivery error notification

   If the sending provider does not receive a take in charge or
   delivery notification from the receiving provider within 12 hours
   after message dispatch, it informs the user that the recipient's
   provider might not be able to deliver the message. In case the
   sending provider doesn't receive a delivery notification within
   24 hours after message dispatch, it emits another non-delivery



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   notification to the user by the 24-hour timeout, but not before
   22 hours have passed.

   Such a communication takes place through a notification of non-
   delivery due to timeout, the header of which contains the following
   fields:

        X-Ricevuta: preavviso-errore-consegna
        Date: [date of notification emission]
        Subject: AVVISO DI MANCATA CONSEGNA PER SUP. TEMPO MASSIMO:
                 [original subject]
        From: certified-mail@[mail_domain]
        To: [original recipient]
        X-Riferimento-Message-ID: [Message-ID of original message]

   The message body of the first non-delivery notification (12-hour
   timeout) is composed of text that represents the readable format
   of the notification, which will relate the following data:

        Non-delivery notification
        On [date] at [time] ([time zone]), the message
        "[subject]" originating from "[original sender]"
        and addressed to "[recipient]"
        has not been delivered within the first 12 hours following
        its dispatch. Not excluding that the message might eventually
        be delivered, it is deemed useful to consider that dispatch
        might not have a positive outcome. The system will see to
        sending another non-delivery notification if in the following
        twelve hours no confirmation is received from the recipient.
        Message identification: [Message-ID]

   On the other hand, 24-hour-timeout induced notifications, who have
   the same header as described above, will have the following text in
   their body:

        Non-delivery notification
        On [date] at [time] ([time zone]), the message
        "[subject]" originating from "[original sender]"
        and addressed to "[recipient]"
        has not been delivered within 24 hours of its dispatch.
        The transaction is deemed to be considered terminated with a



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        negative outcome.
        Massage identification: [Message-ID]

   The same certification data is inserted in an XML file and attached
   to both notification types to allow automatic checks (section 4.4).
   Within the notification other attachments MAY be present for
   specific functionalities supplied by the PEC provider; nonetheless
   the original message MUST NOT be included.

   A timeout notification is generated if one of the following
   scenarios occurs:

   o the sending provider receives a take in charge notification during
     the first 12 hours following message dispatch, but does not
     receive a delivery notification at all. In this case it would be a
     24-hour timeout notification.

   o the sending provider does not receive a take in charge
     notification, but receives a delivery notification after 12 hours
     and before the 24-hour timeout. In this case it would be a 12-hour
     timeout notification.

   o the sending provider doesn't receive either a take in charge
     notification nor a delivery notification. In this case 2 timeout
     notifications are generated; a 12-hour and a 24-hour timeout
     notification.

3.2. Incoming point

3.2.1. Take in charge notification

   When correct PEC transport envelopes (as defined in section 2.2.2.)
   are exchanged between PEC providers, the receiver MUST dispatch a
   take in charge notification to the sender. The dispatched take in
   charge notifications concern all recipients to whom the incoming
   message was addressed, as stated in the routing data (forward and
   reverse paths) of the SMTP transaction. Within the certification
   data of a single take in charge notification, all recipients of the
   message to which it refers are listed. In general, when receiving a
   transport envelope, each provider MUST emit one or more take in
   charge notifications in order to cover, in absence of SMTP transport
   errors, all the recipients in its jurisdiction.

   The header of a take in charge notification contains the following
   fields:





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        X-Ricevuta: presa-in-carico
        Date: [date of take in charge]
        Subject: PRESA IN CARICO: [original subject]
        From: certified-mail@[mail_domain]
        To: [sender provider service mailbox]
        X-Riferimento-Message-ID: [Message-ID of original message]

   The provider's service mail address is obtained from the PEC
   providers directory during the necessary queries made in the
   signature verification stage.

   The notification body is constructed following the underlying model:

        take in charge notification
        On [date] at [time] ([time zone]), the message "[subject]"
        originating from "[original sender]" and addressed to:
        [recipient_1] (["certified mail" | "ordinary mail"])
        [recipient_2] (["certified mail" | "ordinary mail"])
        .
        .
        .
        [recipient_n] (["certified mail" | "ordinary mail"])
        was accepted by the system.
        Message identification: [Message-ID]

   The same certification data is inserted in an XML file which is
   added to the notification message to allow for automatic checks
   (section 4.4). The take in charge notification MAY contain
   additional attachments included by the provider for provider-
   specific services.

3.2.2. Anomaly envelope

   If the tests on an incoming message detect an error, or the message
   is identified as being ordinary mail and the provider is set to
   forward it to the recipient, the system MUST insert such a message
   in an anomaly envelope. Before delivery, the entire message received
   at the incoming point is inserted in an [EMAIL]-compliant format as
   an attachment inside a new message that MUST inherit the values for
   the following header fields unmodified from the received message:

   o Received

   o To

   o Cc




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   o Return-Path

   o Message-ID

   Whereas, the following header fields MUST be modified or inserted:

        X-Trasporto: errore
        Date: [message arrival date]
        Subject: ANOMALIA MESSAGGIO: [original subject]
        From: "On behalf of: [original sender]"
                             <certified-mail@[mail_domain]>
        Reply-To: [original sender (inserted only if not already
                  present)]

   The body is composed of user-readable text according to a model
   that relates the following data:

        Message anomaly
        On [date] at [time] ([time zone]), the message "[subject]"
        originating from "[original sender]" and addressed to:
        [recipient_1]
        [recipient_2]
        .
        .
        .
        [recipient_n]
        was received.
        The data has not been certified due to the following error:
        [concise description of error]
        The original message is attached.

   Due to uncertainty regarding origin and/or conformity of the message
   received, the anomaly envelope MUST NOT contain attachments other
   than the entire message that arrived at the incoming point.

   Note that the routing data of such an envelope (forward and reverse
   paths) remain unaltered. Doing so guarantees both the forwarding of
   the message to the recipients, and the reception of SMTP error
   notifications, if any occur, by the sender (as specified in [SMTP] &
   [SMTP-DSN]).









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3.2.3. Virus detection notification

   If the incoming point receives virus-infected PEC messages, it MUST
   NOT forward them, rather it MUST inform the sending provider, which
   will in turn inform the sending user, of the failed transmission.
   A separate notification of virus detection MUST be sent on behalf of
   every recipient within the provider's domain.

   In case a virus is detected during the reception phase of a message
   whose origin was asserted through sender signature verification,
   the system generates a virus-detected notification, indicating the
   error found, and sends it to the sending provider's service mailbox.

   For this kind of notification, the header contains the following
   fields:

        X-Ricevuta: rilevazione-virus
        X-Sender: [original sender]
        Date: [date of notification emission]
        Subject: PROBLEMA DI SICUREZZA: [original subject]
        From: certified-mail@[mail_domain]
        To: [sender provider notifications]
        X-Riferimento-Message-ID: [Message-ID of original message]

   The body is composed of readable text according to a model which
   relates the following data:

        Virus detection notification
        On [date] at [time] ([time zone]), in the message "[subject]"
        originating from "[original sender]" and addressed to
        "[recipient]"
        a security problem was detected [ID of content type detected].
        Message identification: [Message-ID]

   The same certification data is inserted in an XML file and attached
   to the notification to allow for automatic checks (section 4.4).
   The virus detection notification MAY contain additional attachments
   included by the provider for provider-specific services, regardless
   the original message MUST NOT be included.

   The message body MUST contain the reason for which the transmission
   could not be completed.







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3.2.4. Virus-induced delivery error notification

   At the arrival of a virus detected notification from the receiving
   provider, the sender provider emits a non-delivery notification to
   the sending user.

   The header for this notification contains the following fields:

        X-Ricevuta: errore-consegna
        X-VerificaSicurezza: errore
        Date: [date of notification emission]
        Subject: AVVISO DI MANCATA CONSEGNA PER VIRUS: [original
                 subject]
        From: certified-mail@[mail_domain]
        To: [original sender]
        X-Riferimento-Message-ID: [Message-ID of original message]

   The body is composed of readable text according to the following
   data:

        Delivery error notification due to virus
        On [date] at [time] ([time zone]), in the message "[subject]"
        addressed to "[recipient]"
        a security problem was detected [ID of content type detected
        by the anti-virus].
        The message was not delivered.
        Message identification: [Message-ID]

   All the information necessary for the construction of such a
   notification can be obtained from the correlated virus-detected
   notification.

   The same certification data is inserted in an XML file and attached
   to the notification message to allow for automatic checks (section
   4.4). The notification MAY contain additional attachments included
   by the provider for provider-specific services. The reason why the
   transaction was not completed MUST be specified within the message
   body.

3.3. Delivery point

3.3.1. Checks on incoming messages

   When a message arrives at the delivery point, the system verifies:

   O message type




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   O whether or not a notification has to be returned to the sender.

3.3.2. Delivery notification

   A delivery notification is issued only after a correct PEC transport
   envelope has been delivered to the recipient's mailbox.
   The transport envelope can be easily determined from the presence
   of the following header field:

        X-Trasporto: posta-certificata

   In all other cases (e.g. anomaly envelopes, notifications), the
   delivery notification is not issued. Regardless, the message
   received at the delivery point MUST be delivered to the recipient's
   mailbox unchanged.

   This notification tells the user that his/her message has been
   successfully delivered to the specified recipient. It includes
   readable text, that certifies the date and time of delivery, sender
   and receiver data, and the subject. It also contains an XML
   certification data file, and other optional attachments for
   functionalities offered by the provider.

   The following fields are inserted in the header:

        X-Ricevuta: avvenuta-consegna
        Date: [delivery date]
        Subject: CONSEGNA: [original subject]
        From: certified-mail@[mail_domain]
        To: [original sender]
        X-Riferimento-Message-ID: [Message-ID of original message]

   The value of the "X-TipoRicevuta" header field in the transport
   envelope is derived from the original message, thus allowing the
   sender to determine the type of delivery notification requested
   from the primary recipients of the original message.

3.3.2.1. Delivery notification: complete

   This is the default value for delivery notifications. When no value
   for the "X-TipoRicevuta" is specified, or when it contains the value
   "complete", the system will require a complete delivery notification
   from addressees in the "To:" field, while a concise notification
   (section 3.3.2.3) will be required from those in the "Cc:" field.
   The distinction between primary recipients and those




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   in carbon copy is done through an analysis of the "To:" and "Cc:"
   fields. For notifications sent on behalf of primary recipients, a
   complete copy of the original message along with any attachments
   is inserted in the notification. In case the system in charge of
   delivery is not able to determine the recipient type due to
   ambiguity problems in the "To:" and "Cc:" fields, delivery MUST be
   considered as if addressed to a primary recipient and include the
   complete copy of the original message.

   The notification body is composed of readable text according to a
   model that relates the following certification data:

        Delivery notification
        On [date] at [time] ([time zone]), the message "[subject]"
        originating from "[original sender]" and addressed to
        "[recipient]"
        was placed in the destination's mailbox.
        Message identification: [Message-ID]

   The same certification data is inserted in an XML file and attached
   to the notification (section 4.4), along with any other attachments
   that MAY be inserted by the provider for provider-specific services.
   The delivery notification MUST be issued on the behalf of every
   recipient of the message.

3.3.2.2. Delivery notification: brief

   In order to decrease the amount of data flowing, it is possible
   for the sender to ask for a delivery notification in "brief" format.
   The brief delivery notification contains the original message and a
   ciphered hash value of each attachment. To be able to verify the
   transmitted contents, it is necessary for the sender to keep the
   unaltered original copy of the attachment(s), to which the hash
   values refer.

   If the transport envelope contains the header

        X-TipoRicevuta: breve

   the delivery point emits a brief delivery notification on behalf
   of the primary recipients, and a concise one (section 3.3.2.3) on
   behalf of carbon copy recipients. The value of the header in the
   transport envelope is derived from the original message.

   The notification body is composed of readable text according to a
   model that relates the following certification data:




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        Brief delivery notification
        On [date] at [time] ([time zone]), the message "[subject]"
        originating from "[original sender]" and addressed to
        "[recipient]"
        was placed in the destination's mailbox.
        Message identification:  [Message-ID]

   The same certification data is inserted in an XML file and attached
   to the notification (section 4.4), along with other optional
   attachments specific to provider-supplied functionalities. The
   delivery notification is issued on behalf of every recipient of the
   message.

   The MIME structure of the original message is unaltered as it is
   attached to the notification, but its attachment(s) are substituted
   with as many text files as the attachments are, each containing the
   hash value of the file it substitutes. The attachments are
   identified through the presence of the "name" parameter in the
   header "content-type", or "filename" in the header "content-
   disposition" of the MIME part.

   When the original message has an S/MIME format, it is necessary
   not to alter the integrity of the message structure. Verification
   of the S/MIME message in the original message takes place when
   the MIME type of the top-level entity (which coincides with the
   message itself) is checked. An S/MIME message MAY have the following
   MIME types (as per [SMIMEV3]):

   o multipart/signed

     Represents an original message signed by the sender using the
     structure described in [MIME-SECURE]. The message is made up of 2
     MIME parts: the first is the message itself before the application
     of the sender's signature, whereas the second contains signature
     data. The second part (generally of type "application/pkcs7-
     signature" or "application/x-pkcs-signature") contains data added
     during the signing phase and MUST be left unchanged to avoid
     compromising the overall message structure;

   o "application/pkcs7-mime" or "application/x-pkcs7-mime"

     The message is composed of a sole CMS object within the MIME part.
     Given that attachments cannot be separated from the CMS object,
     the MIME part is left intact (i.e., it is not replaced by the hash
     value); therefore, the brief notification is the same as the
     complete notification.





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   If the original message contains attachments whose content-type
   is "message/rfc822", i.e. contains an email message as attachment,
   the entire attached message is substituted with its corresponding
   hash value.

   Therefore, when emitting a brief delivery notification, the provider
   MUST:

   1. Identify and extract all the attachments from the first MIME
      part of the multipart/signed S/MIME message;

   2. calculate the hash values of all the files attached by the sender
      to the original message;

   3. substitute originals with their hash values.

   In general, in the case of original messages in S/MIME format, the
   copy of the message inserted within the brief delivery notification
   will have the following characteristics:

   o if the original message is signed, the S/MIME structure and
     signature-relative data will remain unchanged. The message will
     generate an error in a future signature integrity verification
     phase following the substitution of attachments with the
     corresponding hash values.

   o if the original message contains the "application/pkcs7-mime" or
     "application/x-pkcs7-mime" MIME type, attachments present in the
     message will not be substituted by their hash values, due to
     impossibility of identification within a CMS structure.
     The content of the brief delivery notification will coincide with
     that of a normal delivery notification.

   The algorithm used for hash calculation is the [SHA1], calculated on
   the entire content of the attachment. To allow distinction between
   hash files and the files to which they refer, the suffix ".hash" is
   added to the original filename. The hash value is written in the
   file using a hexadecimal representation as a single sequence of 40
   characters. The MIME type of these attachments is set to
   "text/plain" to highlight their textual nature.

3.3.2.3. Delivery notification: concise

   If the transport envelope contains the header

        X-TipoRicevuta: sintetica




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   the delivery point emits, both to primary and carbon copy
   recipients, a concise delivery notification that does not contain
   the original message.

   The message body of the notification is composed of readable text
   according to a model that relates the following certification data:

        Concise delivery notification
        On [date] at [time] ([time zone]), the message "[subject]"
        originating from "[original sender]" and addressed to
        "[recipient]"
        was placed in the destination's mailbox.
        Message identification:  [Message-ID]

   The same certification data is inserted within an XML file and
   attached to the notification (section 4.4), along with additional
   attachments that MAY be included by the provider for provider-
   specific services. The notification is sent to each one of the
   recipients to whom the message is delivered.

   The concise delivery notification follows the same emission rules as
   the delivery notification; attached to it is the XML file which
   contains the certification data only, without the original message.

3.3.3. Non-delivery notification

   If an error occurs during the delivery of a correct PEC transport
   message, the system returns to the sender a non-delivery
   notification that indicates the error condition.

   The header will contain the following fields:

        X-Ricevuta: errore-consegna
        Date: [date of notification emission]
        Subject: AVVISO DI MANCATA CONSEGNA: [original subject]
        From: certified-mail@[mail_domain]
        To: [original sender]
        X-Riferimento-Message-ID: [Message-ID of original message]

   The notification body is composed of readable text according to a
   model that relates the following data:

        Non-delivery notification
        On [date] at [time] ([time zone]), in the message "[subject]"
        originating from "[original sender]" and addressed to





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        "[recipient]"
        an error was detected.
        The message was refused by the system.
        Message identification:  [Message-ID]

   The same certification data is inserted within an XML file and
   added to the notification in order to allow for automatic checks
   (section 4.4). The non-delivery notification MAY contain additional
   attachments included by the PEC provider for provider-specific
   services.

3.4. Sender and receiver belonging to the same domain

   PEC messages MUST be processed even if both sender and receiver(s)
   belong to the same PEC domain.

3.5. Example: Complete transaction between 2 PEC domains

   A correct transaction between two PEC domains goes through the
   following steps:

   o The sending user sends an email to his provider's Access Point;

   o The Access Point runs all checks and emits an acceptance
     notification to the user;

   o The Access Point creates a transport envelope and forwards it to
     the Incoming Point of the receiving provider;

   o The receiver's Incoming Point verifies the transport envelope and
     creates a take in charge notification to be sent to the sending
     provider;

   o The sender's Incoming Point verifies the validity of the take in
     charge notification and forwards it to the Delivery Point;

   o The sender's Delivery Point saves the take in charge notification
     in the provider's service mailbox;

   o The receiver's Incoming Point forwards the transport envelope to
     the receiver's Delivery Point;

   o The receiver's Delivery Point verifies the contents of the
     transport envelope and saves it in the recipient's mailbox;






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   o The receiver's Delivery Point creates a delivery notification and
     sends it to the sender's Incoming Point;

   o The sender's Incoming Point verifies the validity of the delivery
     notification and forwards it to the sender's Delivery Point;

   o The sender's Delivery Point saves the delivery notification in the
     sending user's mailbox;

   o The receiving user has the message at his disposition.



4. Formats

4.1. Temporal reference

   For all operations carried out during message, notification, and
   log elaboration processes by the access, incoming and delivery
   points, it is necessary to have an accurate temporal reference
   available. All events (generation of notifications, transport
   envelopes, logs, etc) that constitute the transaction of message
   elaboration at the access, incoming, and delivery points MUST employ
   a sole temporal value obtained from within the transaction itself.
   Doing this renders the instant of message elaboration unambiguous
   within logs, notifications, messages, etc, generated by the server.

4.2. User date/time

   Temporal indications supplied by the service in readable format
   (text in notifications, transport envelopes, etc) are provided
   with reference to the legal time at the moment of the operation.
   The date employs the format, "dd/mm/yyyy", whereas the hour uses
   the format, "hh:mm:ss", where "hh" is in 24hour format. The date
   and time are followed by the time zone, i.e. the difference (hours
   and minutes) between local time and UTC, inserted between
   parentheses. Representation of such a value is in the "[+|-]hhmm"
   format, where the first character indicates a positive or negative
   difference.

4.3. Attachments

   This section describes the characteristics of the various components
   of messages and notifications generated by a PEC system. If one of
   the message parts contains characters with





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   values outside of the interval 0-127 (7-bit ASCII), that part will
   have to be adequately encoded so that 7-bit transportation
   compatibility is guaranteed (e.g. quoted-printable, base64).

4.3.1. Message body

   Character set: ISO-8859-1 (Latin-1)
   MIME type: text/plain or multipart/alternative

   The multipart/alternative MIME type MAY be used to add an HTML
   version of the body of messages generated by the system. In this
   case, two sub-parts MUST be present: one of type text/plain, the
   other text/html. For the HTML part:

   o it MUST contain the same information as related in the text part;

   o it MUST NOT contain references to elements (e.g. images, sounds,
     font, style sheets) neither internal to the message (added MIME
     parts) nor external (e.g. hosted on the provider's server);

   o MUST NOT have active content (e.g. JavaScript, VBscript, Plug-in,
     ActiveX).

4.3.2. Original message

   MIME type: message/rfc822
   Attachment name: certmail.eml

4.3.3. Certification data

   Character set: UTF-8
   MIME type: application/xml
   Attachment name: certdata.xml

4.4. Certification data scheme

   Following is the DTD relative to the XML file that contains
   certification data attached to the notifications.



       <?xml version="1.0" encoding="UTF-8"?>
       <!--Use the element "postacert" as root-->
       <!--"tipo" indicates the typology of the PEC message-->
       <!--The attribute "errore" can have the following values-->





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       <!--"nessuno" = no error-->
       <!--"no-dest" (with type="errore-consegna") = -->
       <!--                                        wrong recipient-->
       <!--"no-dominio" (with type="errore-consegna") = -->
       <!--                                           wrong domain-->
       <!--"virus" (with type="errore-consegna") = virus-->
       <!--"virus" (with type="non-accettazione") = virus-->
       <!--"altro" = generic error-->
       <!ELEMENT postacert (intestazione, dati)>
       <!ATTLIST postacert
             tipo (accettazione |
                   non-accettazione |
                   presa-in-carico |
                   avvenuta-consegna |
                   posta-certificata |
                   errore-consegna |
                   preavviso-errore-consegna |
                   rilevazione-virus) #REQUIRED
             errore (nessuno |
                     no-dest |
                     no-dominio |
                     virus |
                     altro) "nessuno">

       <!--Header of the original message-->
       <!ELEMENT intestazione (mittente,
                               destinatari+,
                               risposte,
                               oggetto?)>

       <!--Sender ("From" field) of the original message-->
       <!ELEMENT mittente (#PCDATA)>

       <!--Complete list of recipients ("To" and "Cc" fields)-->
       <!--of the original message-->
       <!--"tipo" indicates the typology of the recipient-->
       <!ELEMENT destinatari (#PCDATA)>
       <!ATTLIST destinatari
             tipo (certificato | esterno) "certificato">

       <!--Value of the "Reply-To" field of the original message-->
       <!ELEMENT risposte (#PCDATA)>
       <!--Value of the "Subject" field of the original message-->
       <!ELEMENT oggetto (#PCDATA)>

       <!--PEC message data-->
       <!ELEMENT dati (gestore-emittente,



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                       data,
                       identificativo,
                       msgid?,
                       ricevuta?,
                       consegna?,
                       ricezione*,
                       errore-esteso?)>

       <!--Descriptive string of the provider that certifies -->
       <!--the data-->
       <!ELEMENT gestore-emittente (#PCDATA)>

       <!--Date/time of message elaboration-->
       <!--"zona" is the difference between local time and UTC in -->
       <!--"[+|-]hhmm" format-->
       <!ELEMENT data (giorno, ora)>
       <!ATTLIST data
             zona CDATA #REQUIRED>

       <!--Day in "dd/mm/yyyy" format-->
       <!ELEMENT giorno (#PCDATA)>

       <!--Local hour in "hh:mm:ss" format-->
       <!ELEMENT ora (#PCDATA)>

       <!--PEC msgid-->
       <!ELEMENT identificativo (#PCDATA)>

       <!--msgid of the original message before modifications-->
       <!ELEMENT msgid (#PCDATA)>

       <!--For transport envelopes and delivery notifications-->
       <!--indicate the type of notification requested by the-->
       <!-sender-->
       <!ELEMENT ricevuta EMPTY>
       <!ATTLIST ricevuta
             tipo (completa |
                   breve   |
                   sintetica ) #REQUIRED>

       <!--For delivery, non-delivery, virus-induced non-delivery, -->
       <!-- virus detection, and timeout notifications-->
       <!--Recipient address to which delivery has been carried -->
       <!--out/tried-->
       <!ELEMENT consegna (#PCDATA)>

       <!--For take in charge notifications-->



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       <!--recipients for whom it is the relative notification-->
       <!ELEMENT ricezione (#PCDATA)>

       <!--In case of error-->
       <!--brief description of the error-->
       <!ELEMENT errore-esteso (#PCDATA)>

4.5. PEC providers directory scheme

   The PEC providers directory is created through a centralized LDAP
   server that contains providers' data and their corresponding PEC
   mail domains. The directory's base root is "o=certmail", and the
   "DistinguishedName" of single records are of the type,
   "providerName=<name>, o=certmail". Search within the directory is
   carried out mainly in case-sensitive mode using the
   "providerCertificateHash" attributes (during envelope signature
   verification phase) or "managedDomains" (during message acceptance
   phase). It is possible for the record of a single provider to
   contain multiple "providerCertificate", and the corresponding
   "providerCertificateHash", attributes in order to allow the handling
   of the renewal of expiring certificates. The provider MUST make sure
   to update its own record sufficiently beforehand with respect to
   the expiration date of the certificate, by adding a new certificate
   whose validity overlaps with that of the previous one. The
   "LDIFLocationURL" attribute MUST point to an HTTPS object supplied
   by the provider, and containing an LDIF file according to [LDIF]. To
   guarantee authenticity, the file MUST be signed by the provider for
   the operations regarding its PEC services. The LDIF file, the
   signature, and the X.509v3 certificate MUST be inserted in a PKCS#7
   structure in binary ASN.1 DER format as a file with ".p7m"
   extension. The centralized LDAP system downloads such a file on a
   daily basis, and, after opportune verifications of the appended
   signature, it applies it to the record relative to the provider.
   The LDIF file that encompasses the data of all the PEC providers
   is available, signed using the method described for single providers
   as an HTTPS object, and can be found at the URL to which the
   "LDIFLocationURL" attribute in the "dn: o=certmail" record points.
   Through the LDIF file, single providers HAVE TO keep a local copy of
   the directory, updated on a daily basis, in order to improve system
   performance by avoiding continuous request dispatches to the central
   system for every message elaboration phase.

   It is possible for the provider to define several distinct records
   to indicate different secondary, administered operating
   environments. Every record refers to a single secondary operating





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   environment for which it is possible to declare specific attributes,
   and if need be distinct from those relative to other environments
   and to the main environment. All records MUST contain the name of
   the provider in the "providerName" attribute, whereas the
   "providerUnit" attribute is used to identify the secondary operating
   environments. The "DistinguishedName" of the records relative to the
   secondary operating environments are of the type
   "providerUnit=<environment>,providerName=<name>,o=certmail". Every
   provider MUST have a record associated to its own main environment,
   distinguishable for the absence of the "providerUnit" attribute
   within the record and the DistinguishedName. Records for secondary
   environments MUST contain the "LDIFLocationURL" attribute, which
   is obtained from the main environment's attribute for all records
   connected to the provider. If secondary environments are present,
   the LDIF found in the main environment's record MUST hold the
   contents of all the provider-relevant records.

   Following are the attributes defined for the scheme of the PEC
   providers directory:

   - providerCertificateHash: IA5 string
     Hexadecimal representation of the hash in SHA1 format of the
     X.509v3 certificate used by the provider for notifications and
     PEC envelope signatures.

   - providerCertificate: Certificate Binary transfer
     Certificate(s) used by the provider for signing notifications and
     transport envelopes.

   - providerName: Directory string Single value
     Name of PEC provider.

   - mailReceipt: IA5 string Single value
     Email address to which take in charge notifications and virus
     detection notifications are sent.

   - managedDomains: IA5 string
     PEC domains handled by the provider.

   - LDIFLocationURL: Directory string Single value
     HTTPS URL where the definition of the record related to the
     provider is maintained in LDIF format. When the attribute is
     present in the record "dn: o=postacert", then it contains the
     definition of the entire directory in LDIF format.






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   - providerUnit: Directory string Single value
     Name of the secondary operating environment (not available for
     the principal environment)

   Next is the LDAP scheme for the PEC providers directory according
   to the syntax described in [LDAP]:



       attributetype ( 16572.2.2.1
               NAME 'providerCertificateHash'
               DESC 'Hash SHA1 of X.509 certificate in hexadecimal
                     format'
               EQUALITY caseIgnoreIA5Match
               SYNTAX 1.3.6.1.4.1.1466.115.121.1.26{40} )

       attributetype ( 16572.2.2.2
               NAME 'providerCertificate'
               DESC 'X.509 certificate in ASN.1 DER binary format'
               SYNTAX 1.3.6.1.4.1.1466.115.121.1.8 )

       attributetype ( 16572.2.2.3
               NAME 'providerName'
               DESC 'PEC provider'
               EQUALITY caseIgnoreMatch
               SUBSTR caseIgnoreSubstringsMatch
               SYNTAX 1.3.6.1.4.1.1466.115.121.1.15{32768}
               SINGLE-VALUE )

       attributetype ( 16572.2.2.4
               NAME 'mailReceipt'
               DESC 'E-mail address of the service mailbox'
               EQUALITY caseIgnoreIA5Match
               SUBSTR caseIgnoreIA5SubstringsMatch
               SYNTAX 1.3.6.1.4.1.1466.115.121.1.26{256}
               SINGLE-VALUE )

       attributetype ( 16572.2.2.5
               NAME 'managedDomains'
               DESC 'Domains handled by the PEC provider'
               EQUALITY caseIgnoreIA5Match
               SUBSTR caseIgnoreIA5SubstringsMatch
               SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )

       attributetype ( 16572.2.2.6
               NAME 'LDIFLocationURL'
               DESC 'URL of the LDIF file that defines the entry'



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               EQUALITY caseExactMatch
               SYNTAX 1.3.6.1.4.1.1466.115.121.1.15
               SINGLE-VALUE )

       attributetype ( 16572.2.2.7
               NAME 'providerUnit'
               DESC 'Name of the secondary operative environment'
               EQUALITY caseIgnoreMatch
               SUBSTR caseIgnoreSubstringsMatch
               SYNTAX 1.3.6.1.4.1.1466.115.121.1.15{32768}
               SINGLE-VALUE )

       objectclass ( 16572.2.1.1
               NAME 'LDIFLocationURLObject'
               DESC 'Class for the insertion of a LDIFLocationURL
                     attribute'
               MAY ( LDIFLocationURL )
               SUP top AUXILIARY )

       objectclass ( 16572.2.1.2
               NAME 'provider'
               DESC 'PEC provider'
               SUP top
               MUST    ( providerCertificateHash $
                         providerCertificate $
                         providerName $
                         mailReceipt $
                         managedDomains)
               MAY     ( description $
                         LDIFLocationURL $
                         providerUnit) )


   The following LDIF file represents an example of a providers'
   directory, containing a base root and 2 fictitious providers. The
   inserted certificates are two self-signed certificates used for
   example purposes only:


       dn: o=postacert
       objectclass: top
       objectclass: organization
       objectClass: LDIFLocationURLObject
       o: postacert
       LDIFLocationURL: https://igpec.rupa.it/igpec.ldif.p7m
       description: Base root for the PEC providers directory




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       dn: providerName=Anonymous Certified Mail S.p.A.,o=postacert
       objectclass: top
       objectclass: provider
       providerName: Anonymous Certified Mail S.p.A.
       providerCertificateHash:
        7E7AEF1059AE0F454F2643A95F69EC3556009239
       providerCertificate;binary::
        MIIDBjCCAm+gAwIBAgIBADANBgkqhkiG9w0BAQQFADBmMQswCQYDVQQGEw
        JJVDEpMCcGA1UEChMgQW5vbmltYSBQb3N0YSBDZXJ0aWZpY2F0YSBTLnAu
        QS4xLDAqBgkqhkiG9w0BCQEWHXBvc3RhLWNlcnRpZmljYXRhQGFucG9jZX
        J0Lml0MB4XDTAyMTIwOTE3MjQxNVoXDTAzMTIwOTE3MjQxNVowZjELMAkG
        A1UEBhMCSVQxKTAnBgNVBAoTIEFub25pbWEgUG9zdGEgQ2VydGlmaWNhdG
        EgUy5wLkEuMSwwKgYJKoZIhvcNAQkBFh1wb3N0YS1jZXJ0aWZpY2F0YUBh
        bnBvY2VydC5pdDCBnzANBgkqhkiG9w0BAQEFAAOBjQAwgYkCgYEAr8J+qK
        KdxV9LzDMPqwnEy0P8H/KwbI0Szs8p6UZajZdpeUK0Ncbrv1QyXZNNtSMC
        2uL09HDyx8agjgZWdhypnehguiSK3busha15RSpMGhiqxmz2b0HhOG73Gf
        alZelqrwqmElna4MNUaLhbOvTd/sqPUS378w5IaIhWxzy34XcCAwEAAaOB
        wzCBwDAdBgNVHQ4EFgQUN8lC0znQWEs0xspZ/aBzsaGvRZMwgZAGA1UdIw
        SBiDCBhYAUN8lC0znQWEs0xspZ/aBzsaGvRZOhaqRoMGYxCzAJBgNVBAYT
        AklUMSkwJwYDVQQKEyBBbm9uaW1hIFBvc3RhIENlcnRpZmljYXRhIFMucC
        5BLjEsMCoGCSqGSIb3DQEJARYdcG9zdGEtY2VydGlmaWNhdGFAYW5wb2Nl
        cnQuaXSCAQAwDAYDVR0TBAUwAwEB/zANBgkqhkiG9w0BAQQFAAOBgQA58B
        Z+q1qSKpuffzTBpMtbeFkDIxMqMa+ycnxdMNvcWgCm1A9ZiFJsvqYhDDqA
        XxfHjkrzXuSZkYq6WiQCsLp0aYVy40QCIwbOunhrvsxh3vsG5CgN76JzZ9
        5Z/1OCFNhLfqf1VH2NSS8TaYCCi/VO7W1Q1KkcA2VlxlQP7McSUw==
       mailReceipt: ricevute@anpocert.it
       LDIFLocationURL: https://www.anpocert.it/LDIF/anpocert.ldif.p7m
       managedDomains: mail.anpocert.it.example
       managedDomains: cert.company.it.example
       managedDomains: costmec.it.example
       description: Certified mail services for companies

       dn: providerName=Postal Services S.p.A,o=postacert
       objectclass: top
       objectclass: provider
       providerName: Postal Services S.p.A
       providerCertificateHash:
        e00fdd9d88be0e2cc766b893315caf93d5701a6a
       providerCertificate;binary::
        MIIDHjCCAoegAwIBAgIBADANBgkqhkiG9w0BAQQFADBuMQswCQYDVQQGEw
        JJVDEfMB0GA1UEChMWU2Vydml6aSBQb3N0YWxpIFMuci5sLjEPMA0GA1UE
        CxMGRC5DLkMuMS0wKwYJKoZIhvcNAQkBFh5wb3N0YS1jZXJ0aWZpY2F0YU
        BzZXJwb3N0YWwuaXQwHhcNMDIxMjA5MTczMjE2WhcNMDMxMjA5MTczMjE2
        WjBuMQswCQYDVQQGEwJJVDEfMB0GA1UEChMWU2Vydml6aSBQb3N0YWxpIF
        Muci5sLjEPMA0GA1UECxMGRC5DLkMuMS0wKwYJKoZIhvcNAQkBFh5wb3N0
        YS1jZXJ0aWZpY2F0YUBzZXJwb3N0YWwuaXQwgZ8wDQYJKoZIhvcNAQEBBQ
        ADgY0AMIGJAoGBAKoc7n6zA+sO8NATMcfJ+U2aoDEsrj/cObG3QAN6Sr+l



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        ygWxYXLBZNfSDWqL1K4edLr4gCZIDFsq0PIEaYZhYRGjhbcuJ9H/ZdtWdX
        xcwEWN4mwFzlsASogsh5JeqS8db3A1JWkvhO9EUfaCYk8YMAkXYdCtLD9s
        9tCYZeTE2ut9AgMBAAGjgcswgcgwHQYDVR0OBBYEFHPw7VJIoIM3VYhuHa
        eAwpPF5leMMIGYBgNVHSMEgZAwgY2AFHPw7VJIoIM3VYhuHaeAwpPF5leM
        oXKkcDBuMQswCQYDVQQGEwJJVDEfMB0GA1UEChMWU2Vydml6aSBQb3N0YW
        xpIFMuci5sLjEPMA0GA1UECxMGRC5DLkMuMS0wKwYJKoZIhvcNAQkBFh5w
        b3N0YS1jZXJ0aWZpY2F0YUBzZXJwb3N0YWwuaXSCAQAwDAYDVR0TBAUwAw
        EB/zANBgkqhkiG9w0BAQQFAAOBgQApqeXvmOyEjwhMrXezPAXELMZwv4qq
        r5ri4XuxTq6sS9jRsEbZrS+NmbcJ7S7eFwNQMNxYFVJqdWoLh8qExsTLXn
        sKycSnHbCfuphrKvXjQvR2da75U4zGSkroiyvJ2s9TtiCcT3lQtIjmvrFb
        aSBiyzj+za7foFUCQmxCLtDaA==
       mailReceipt: takecharge@postalser.it
       LDIFLocationURL: https://services.postalser.it/ldif.txt.p7m
       managedDomains: postal-services.it
       managedDomains: receivedmail.it
       description: Certified mail services for the public

   The following LDIF file represents an example of a PEC providers'
   directory, containing a base root and 2 fictitious providers, the
   first of which handles a secondary environment as well. The
   certificates inserted are 2 self-signed certificates used for
   example purposes only:

       dn: o=postacert
       objectclass: top
       objectclass: organization
       objectClass: LDIFLocationURLObject
       o: postacert
       LDIFLocationURL: https://igpec.rupa.it/igpec.ldif.p7m
       description: Base root for the PEC providers directory

       dn: providerName=Anonymous Certified Mail S.p.A.,o=postacert
       objectclass: top
       objectclass: provider
       providerName: Anonymous Certified Mail S.p.A.
       providerCertificateHash:
        7E7AEF1059AE0F454F2643A95F69EC3556009239
       providerCertificate;binary::
        MIIDBjCCAm+gAwIBAgIBADANBgkqhkiG9w0BAQQFADBmMQswCQYDVQQGEw
        JJVDEpMCcGA1UEChMgQW5vbmltYSBQb3N0YSBDZXJ0aWZpY2F0YSBTLnAu
        QS4xLDAqBgkqhkiG9w0BCQEWHXBvc3RhLWNlcnRpZmljYXRhQGFucG9jZX
        J0Lml0MB4XDTAyMTIwOTE3MjQxNVoXDTAzMTIwOTE3MjQxNVowZjELMAkG
        A1UEBhMCSVQxKTAnBgNVBAoTIEFub25pbWEgUG9zdGEgQ2VydGlmaWNhdG
        EgUy5wLkEuMSwwKgYJKoZIhvcNAQkBFh1wb3N0YS1jZXJ0aWZpY2F0YUBh
        bnBvY2VydC5pdDCBnzANBgkqhkiG9w0BAQEFAAOBjQAwgYkCgYEAr8J+qK
        KdxV9LzDMPqwnEy0P8H/KwbI0Szs8p6UZajZdpeUK0Ncbrv1QyXZNNtSMC
        2uL09HDyx8agjgZWdhypnehguiSK3busha15RSpMGhiqxmz2b0HhOG73Gf



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        alZelqrwqmElna4MNUaLhbOvTd/sqPUS378w5IaIhWxzy34XcCAwEAAaOB
        wzCBwDAdBgNVHQ4EFgQUN8lC0znQWEs0xspZ/aBzsaGvRZMwgZAGA1UdIw
        SBiDCBhYAUN8lC0znQWEs0xspZ/aBzsaGvRZOhaqRoMGYxCzAJBgNVBAYT
        AklUMSkwJwYDVQQKEyBBbm9uaW1hIFBvc3RhIENlcnRpZmljYXRhIFMucC
        5BLjEsMCoGCSqGSIb3DQEJARYdcG9zdGEtY2VydGlmaWNhdGFAYW5wb2Nl
        cnQuaXSCAQAwDAYDVR0TBAUwAwEB/zANBgkqhkiG9w0BAQQFAAOBgQA58B
        Z+q1qSKpuffzTBpMtbeFkDIxMqMa+ycnxdMNvcWgCm1A9ZiFJsvqYhDDqA
        XxfHjkrzXuSZkYq6WiQCsLp0aYVy40QCIwbOunhrvsxh3vsG5CgN76JzZ9
        5Z/1OCFNhLfqf1VH2NSS8TaYCCi/VO7W1Q1KkcA2VlxlQP7McSUw==
       mailReceipt: notifications@anpocert.it
       LDIFLocationURL: http://www.anpocert.it/LDIF/anpocert.ldif.p7m
       managedDomains: mail.anpocert.it.example
       managedDomains: cert.company.it.example
       managedDomains: costmec.it.example
       description: Certified mail services for companies

       dn: providerUnit=Secondary Environment, providerName=Anonymous
        Certified Mail S.p.A.,o=postacert
       objectclass: top
       objectclass: provider
       providerName: Certified Mail S.p.A.
       providerUnit: Secondary Environment
       providerCertificateHash:
        7E7AEF1059AE0F454F2643A95F69EC3556009239
       providerCertificate;binary::
        MIIDBjCCAm+gAwIBAgIBADANBgkqhkiG9w0BAQQFADBmMQswCQYDVQQGEw
        JJVDEpMCcGA1UEChMgQW5vbmltYSBQb3N0YSBDZXJ0aWZpY2F0YSBTLnAu
        QS4xLDAqBgkqhkiG9w0BCQEWHXBvc3RhLWNlcnRpZmljYXRhQGFucG9jZX
        J0Lml0MB4XDTAyMTIwOTE3MjQxNVoXDTAzMTIwOTE3MjQxNVowZjELMAkG
        A1UEBhMCSVQxKTAnBgNVBAoTIEFub25pbWEgUG9zdGEgQ2VydGlmaWNhdG
        EgUy5wLkEuMSwwKgYJKoZIhvcNAQkBFh1wb3N0YS1jZXJ0aWZpY2F0YUBh
        bnBvY2VydC5pdDCBnzANBgkqhkiG9w0BAQEFAAOBjQAwgYkCgYEAr8J+qK
        KdxV9LzDMPqwnEy0P8H/KwbI0Szs8p6UZajZdpeUK0Ncbrv1QyXZNNtSMC
        2uL09HDyx8agjgZWdhypnehguiSK3busha15RSpMGhiqxmz2b0HhOG73Gf
        alZelqrwqmElna4MNUaLhbOvTd/sqPUS378w5IaIhWxzy34XcCAwEAAaOB
        wzCBwDAdBgNVHQ4EFgQUN8lC0znQWEs0xspZ/aBzsaGvRZMwgZAGA1UdIw
        SBiDCBhYAUN8lC0znQWEs0xspZ/aBzsaGvRZOhaqRoMGYxCzAJBgNVBAYT
        AklUMSkwJwYDVQQKEyBBbm9uaW1hIFBvc3RhIENlcnRpZmljYXRhIFMucC
        5BLjEsMCoGCSqGSIb3DQEJARYdcG9zdGEtY2VydGlmaWNhdGFAYW5wb2Nl
        cnQuaXSCAQAwDAYDVR0TBAUwAwEB/zANBgkqhkiG9w0BAQQFAAOBgQA58B
        Z+q1qSKpuffzTBpMtbeFkDIxMqMa+ycnxdMNvcWgCm1A9ZiFJsvqYhDDqA
        XxfHjkrzXuSZkYq6WiQCsLp0aYVy40QCIwbOunhrvsxh3vsG5CgN76JzZ9
        5Z/1OCFNhLfqf1VH2NSS8TaYCCi/VO7W1Q1KkcA2VlxlQP7McSUw==
       mailReceipt: notifications@secondary.anpocert.it
       managedDomains: management.anpocert.it.example
       managedDomains: personnel.anpocert.it.example
       description: Corporate internal services



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       dn: providerName=Postal Services S.r.l.,o=postacert
       objectclass: top
       objectclass: provider
       providerName: Postal Services S.r.l.
       providerCertificateHash:
        e00fdd9d88be0e2cc766b893315caf93d5701a6a
       providerCertificate;binary::
        MIIDHjCCAoegAwIBAgIBADANBgkqhkiG9w0BAQQFADBuMQswCQYDVQQGEw
        JJVDEfMB0GA1UEChMWU2Vydml6aSBQb3N0YWxpIFMuci5sLjEPMA0GA1UE
        CxMGRC5DLkMuMS0wKwYJKoZIhvcNAQkBFh5wb3N0YS1jZXJ0aWZpY2F0YU
        BzZXJwb3N0YWwuaXQwHhcNMDIxMjA5MTczMjE2WhcNMDMxMjA5MTczMjE2
        WjBuMQswCQYDVQQGEwJJVDEfMB0GA1UEChMWU2Vydml6aSBQb3N0YWxpIF
        Muci5sLjEPMA0GA1UECxMGRC5DLkMuMS0wKwYJKoZIhvcNAQkBFh5wb3N0
        YS1jZXJ0aWZpY2F0YUBzZXJwb3N0YWwuaXQwgZ8wDQYJKoZIhvcNAQEBBQ
        ADgY0AMIGJAoGBAKoc7n6zA+sO8NATMcfJ+U2aoDEsrj/cObG3QAN6Sr+l
        ygWxYXLBZNfSDWqL1K4edLr4gCZIDFsq0PIEaYZhYRGjhbcuJ9H/ZdtWdX
        xcwEWN4mwFzlsASogsh5JeqS8db3A1JWkvhO9EUfaCYk8YMAkXYdCtLD9s
        9tCYZeTE2ut9AgMBAAGjgcswgcgwHQYDVR0OBBYEFHPw7VJIoIM3VYhuHa
        eAwpPF5leMMIGYBgNVHSMEgZAwgY2AFHPw7VJIoIM3VYhuHaeAwpPF5leM
        oXKkcDBuMQswCQYDVQQGEwJJVDEfMB0GA1UEChMWU2Vydml6aSBQb3N0YW
        xpIFMuci5sLjEPMA0GA1UECxMGRC5DLkMuMS0wKwYJKoZIhvcNAQkBFh5w
        b3N0YS1jZXJ0aWZpY2F0YUBzZXJwb3N0YWwuaXSCAQAwDAYDVR0TBAUwAw
        EB/zANBgkqhkiG9w0BAQQFAAOBgQApqeXvmOyEjwhMrXezPAXELMZwv4qq
        r5ri4XuxTq6sS9jRsEbZrS+NmbcJ7S7eFwNQMNxYFVJqdWoLh8qExsTLXn
        sKycPSnHbCfuphrKvXjQvR2da75U4zGSkroiyvJ2s9TtiCcT3lQtIjmvrF
        baSBiyzj+za7foFUCQmxCLtDaA==
       mailReceipt: takecharge@postalser.it
       LDIFLocationURL: http://services.postalser.it/ldif.txt.p7m
       managedDomains: postal-services.it
       managedDomains: receivedmail.it
       description: Certified mail services for the public


5. Security-related aspects

5.1. Digital signature

   The private key and signature operations MUST be handled using a
   dedicated hardware security module which is able to guarantee their
   security in compliance with the criteria adopted in the European or
   international setting.

5.2. Authentication

   User access to PEC services through the access point MUST be allowed
   upon authentication on the system by the user himself.



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   For example, authentication modalities might use user-ID and
   password, or, if available and considered necessary for the type
   of service provided, the electronic ID card or the national services
   card. Choice of authentication modality is left to the better
   judgment of the service provider. Authentication is necessary to
   guarantee, as much as possible, that the message is sent by a PEC
   user, whose identification data is congruent with the specified
   sender, so as to avoid falsification of the latter.

5.3. Secure interaction

   In order to guarantee that the original message doesn't change
   during the interaction, envelopment of and signature application
   on outgoing messages is done at the access point, and the subsequent
   verification of incoming messages is done at the incoming point.
   The original message is inserted as attachment within a transport
   envelope. The transport envelope signed by the sending provider
   permits to verify that the original message hasn't been modified
   during its transition from sender domain to receiver domain.

   All communications within the PEC network MUST use secure channels,
   and integrity and confidentiality of the connections between the PEC
   provider and the user MUST be guaranteed through the use of secure
   protocols, such as those based on [TLS] and those that create a
   secure transport channel on which non-secure protocols are conveyed
   (e.g. IPSec).

   The interaction between providers MUST take place using SMTP on
   [TLS], as per [SMTP-TLS]. The incoming point MUST provide and
   announce its support for the STARTTLS extension, as well as accept
   both unencrypted connections (for ordinary mail) and protected ones.

   To guarantee complete traceability in the flow of PEC messages,
   these MUST NOT transit on systems external to the PEC circuit. When
   exchanging messages between different providers, all transactions
   MUST take place between machines that belong to the PEC circuit, or
   those directly managed by the provider. Secondary PEC messages
   reception systems, if present, MUST be under direct control of the
   provider. An "MX" type record MUST be associated to each PEC domain,
   defined within the system for name resolution.









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5.4. Virus

   Another important security aspect, that concerns the entire PEC
   system, is related to the technical and functional architecture
   which MUST block the presence of viruses from endangering the
   security of all handled messages; it is therefore REQUIRED to have
   installations and continuous updates of anti-virus systems that
   hinder infections as much as possible, without intervening on the
   content of the certified mail, in compliance with what has been
   discussed thus far.

5.5. S/MIME certificate

   In this document the S/MIME certificate profile is defined for use
   in the certification of PEC messages done by the providers. The
   proposed profile of the S/MIME certificate is based on the IETF
   standards [SMIMECERT] and [X509], which in turn are based on the
   standard ISO/IEC 9594-8:2001.

5.5.1. Provider-related information (subject)

   The information related to the PEC provider holder of the
   certificate MUST be inserted in the "Subject:" field (Subject DN).

   More precisely, the Subject DN MUST contain the PEC provider's name
   as it is in the "providerName" attribute published in the PEC
   providers directory (section 4.5). The providerName MUST be present
   in the CommonName or OrganizationName attributes of the Subject
   field in the certificate.

   Certificates MUST contain an Internet mail address, which MUST
   have a value in the subjectAltName extension, and SHOULD NOT be
   present in the Subject Distinguished Name.

   Valid subjectDN are:

        C=IT, O=AcmePEC S.p.A, CN=Posta Certificata

        C=IT, O=ServiziPEC S.p.A, CN=Posta Certificata

   Valorization of other attributes in the Subject DN, if present,
   MUST be done in compliance with [X509].

5.5.2. Certificate extensions

   Extensions that MUST be present in the S/MIME certificate are:




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   o Key Usage

   o Authority Key Identifier

   o Subject Key Identifier

   o Subject Alternative Name

   The Basic Constraints extension (Object ID:2.5.29.19) MUST NOT be
   present.

   The valorization of the above listed extensions for the described
   profile follows.

   The Key Usage extension (Object ID: 2.5.29.15) MUST have the
   digitalSignature bit (bit 0) activated and MUST be marked as
   critical. The extension MAY contain other active bits corresponding
   to different Key Usage, as long as that doesn't contrast with the
   indications in [X509].

   The Authority Key Identifier (Object ID:2.5.29.35) MUST contain
   at least the keyIdentifier field, and MUST NOT be marked as
   critical.

   The Subject Key Identifier extension (Object ID: 2.5.29.14) MUST
   contain at least the keyIdentifier field, and MUST NOT be marked as
   critical.

   The Subject Alternative Name (Object ID: 2.5.29.17) MUST contain
   at least the rfc822Name field, and MUST NOT be marked as critical.

   Adding other extensions that have not been described in this
   document is to be considered OPTIONAL, as long as it remains
   compliant with [X509]; such added extension MUST NOT be marked as
   critical.

5.5.3. Example

   Following is an example of an S/MIME certificate compliant with
   the minimal requisites described in this profile. Values used are
   of fictitious providers generated for example purposes only.

5.5.3.1. General-use certificate in annotated version

   An asterisk near the label of an extension means that such an
   extension has been marked as critical.




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       VERSION: 3
       SERIAL: 11226 (0x2bda)
       INNER SIGNATURE:
         ALG. ID: id-sha1-with-rsa-encryption
         PARAMETER: 0
       ISSUER:
       Country Name: IT
         Organization Name: Certifier 1
         Organizational Unit Name: Certification Service Provider
         Common Name: Certifier S.p.A.
       VALIDITY:
         Not Before: Oct 5, 04 09:04:23 GMT
         Not After: Oct 5, 05 09:04:23 GMT
       SUBJECT:
         Country Name: IT
         Organization Name: AcmePEC S.p.A.
         Common Name: Certified Mail
       PUBLIC KEY: (key size is 1024 bits)
       ALGORITHM:
       ALG. ID: id-rsa-encryption
       PARAMETER: 0
       |MODULUS: 0x00afbeb4 5563198a aa9bac3f 1b29b5be
       |         7f691945 89d01569 ca0d555b 5c33d7e9
       |         ...
       |         d15ff128 6792def5 b3f884e6 54b326db
       |         cf
       |EXPONENT: 0x010001
       |EXTENSIONS:
       | Subject Alt Name:
       | RFC Name: posta-certificata@acmepec.it
       | Key Usage*: Digital Signature
       | Authority Key Identifier: 0x12345678 aaaaaaaa bbbbbbbb
       cccccccc

       dddddddd
       | Subject Key Identifier: 0x3afae080 6453527a 3e5709d8 49a941a8

       a3a70ae1
       |SIGNATURE:
         ALG. ID: id-sha1-with-rsa-encryption
         PARAMETER: 0
         VALUE: 0x874b4d25 70a46180 c9770a85 fe7923ce
                 b22d2955 2f3af207 142b2aba 643aaa61
                 ...
                 d8fd10b4 c9e00ebc c089f7a3 549a1907
                 ff885220 ce796328 b0f8ecac 86ffb1cc




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5.5.3.2. General-use certificate in dump asn.1

       0 30  794: SEQUENCE {
       4 30  514:   SEQUENCE {
       8 A0    3:     [0] {
       10 02   1:       INTEGER 2
           :       }
       13 02    2:     INTEGER 11226
       17 30   13:     SEQUENCE {
       19 06    9:       OBJECT IDENTIFIER
           :         sha1withRSAEncryption (1 2 840 113549 1 1 5)
       30 05    0:       NULL
           :       }
       32 30  101:     SEQUENCE {
       34 31   11:       SET {
       36 30    9:         SEQUENCE {
       38 06    3:           OBJECT IDENTIFIER countryName (2 5 4 6)
       43 13    2:           PrintableString 'IT'
           :           }
           :         }
       47 31   28:       SET {
       49 30   26:         SEQUENCE {
       51 06    3:           OBJECT IDENTIFIER organizationName (2 5 4
       10)
       56 13   19:           PrintableString 'Certificatore 1'
           :           }
           :         }
       77 31   22:       SET {
       79 30   20:         SEQUENCE {
       81 06    3:           OBJECT IDENTIFIER organizationalUnitName
       (2 5 4 11)
       86 13   13:           PrintableString 'Certification Service
                                                              Provider'
           :           }
           :         }
       101 31   32:       SET {
       103 30   30:         SEQUENCE {
       105 06    3:           OBJECT IDENTIFIER commonName (2 5 4 3)
       110 13   23:           PrintableString 'Certificatore S.p.A.'
           :           }
           :         }
           :       }
       135 30   30:     SEQUENCE {
       137 17   13:       UTCTime '041005090423Z'
       152 17   13:       UTCTime '051005090423Z'





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           :       }
       167 30   66:     SEQUENCE {
       169 31   11:       SET {
       171 30    9:         SEQUENCE {
       173 06    3:           OBJECT IDENTIFIER countryName (2 5 4 6)
       178 13    2:           PrintableString 'IT'
           :           }
           :         }
       182 31   23:       SET {
       184 30   21:         SEQUENCE {
       186 06    3:           OBJECT IDENTIFIER organizationName (2 5 4
       10)
       191 13   14:           PrintableString 'AcmePEC S.p.A.'
           :           }
           :         }
       207 31   26:       SET {
       209 30   24:         SEQUENCE {
       211 06    3:           OBJECT IDENTIFIER commonName (2 5 4 3)
       216 13   17:           PrintableString 'Posta Certificata'
           :           }
           :         }
           :       }
       235 30  159:     SEQUENCE {
       238 30   13:       SEQUENCE {
       240 06    9:         OBJECT IDENTIFIER rsaEncryption (1 2 840
       113549
                                                                      1
       1 1)
       251 05    0:         NULL
           :         }
       253 03  141:       BIT STRING 0 unused bits
           :         30 81 89 02 81 81 00 AF BE B4 55 63 19 8A AA 9B
           :         AC 3F 1B 29 B5 BE 7F 69 19 45 89 D0 15 69 CA 0D
           :         55 5B 5C 33 D7 E9 C8 6E FC 14 46 C3 C3 09 47 DD
           :         CD 10 74 1D 76 4E 71 14 E7 69 42 BE 1C 47 61 85
           :         4D 74 76 DD 0B B5 78 4F 1E 84 DD B4 86 7F 96 DF
           :         5E 7B AF 0E CE EA 12 57 0B DF 9B 63 67 4D F9 37
           :         B7 48 35 27 C2 89 F3 C3 54 66 F7 DA 6C BE 4F 5D
           :         85 55 07 A4 97 8C D1 5F F1 28 67 92 DE F5 B3 F8
           :                 [ Another 12 bytes skipped ]
           :       }
       397 A3  123:     [3] {
       399 30  121:       SEQUENCE {
       401 30   39:         SEQUENCE {
       403 06    3:           OBJECT IDENTIFIER subjectAltName (2 5 29
       17)
       408 04   32:           OCTET STRING




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           :             30 1E 81 1C 70 6F 73 74 61 2D 63 65 72 74 69
       66
           :             69 63 61 74 61 40 61 63 6D 65 70 65 63 2E 69
       74
           :           }
       442 30   14:         SEQUENCE {
       444 06    3:           OBJECT IDENTIFIER keyUsage (2 5 29 15)
       449 01    1:           BOOLEAN TRUE
       452 04    4:           OCTET STRING
           :             03 02 07 80
           :           }
       458 30   31:         SEQUENCE {
       460 06    3:           OBJECT IDENTIFIER authorityKeyIdentifier
       (2 5
                                                                    29
       35)
       465 04   24:           OCTET STRING
           :             30 16 11 11 11 11 AA AA AA AA AA BB BB BB BB
       CC

       CC
           :             CC CC DD DD DD DD
           :           }
       491 30   29:         SEQUENCE {
       493 06    3:           OBJECT IDENTIFIER subjectKeyIdentifier (2
       5 29

       14)
       498 04   22:           OCTET STRING
           :             04 14 3A FA E0 80 64 53 52 7A 3E 57 09 D8 49
       A9
           :             41 A8 A3 A7 0A E1
           :           }
           :         }
           :       }
           :     }
       522 30   13:   SEQUENCE {
       524 06    9:     OBJECT IDENTIFIER
           :       sha1withRSAEncryption (1 2 840 113549 1 1 5)
       535 05    0:     NULL
           :     }
       537 03  257:   BIT STRING 0 unused bits
           :     87 4B 4D 25 70 A4 61 80 C9 77 0A 85 FE 79 23 CE
           :     B2 2D 29 55 2F 3A F2 07 14 2B 2A BA 64 3A AA 61
           :     1F F0 E7 3F C4 E6 13 E2 09 3D F0 E1 83 A0 C0 F2
           :     C6 71 7F 3A 1C 80 7F 15 B3 D6 1E 22 79 B8 AC 91
           :     51 83 F2 3A 84 86 B6 07 2B 22 E8 01 52 2D A4 50



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           :     9F C6 42 D4 7C 38 B1 DD 88 CD FC E8 C3 12 C3 62
           :     64 0F 16 BF 70 15 BC 01 16 78 30 2A DA FA F3 70
           :     E2 D3 0F 00 B0 FD 92 11 6C 55 45 48 F5 64 ED 98
           :             [ Another 128 bytes skipped ]
           :   }

5.6. PEC providers directory

   The contents of the PEC providers directory MUST be queried via
   HTTP on SSL, as described in [TLS], exclusively by licensed
   providers that have the necessary user certificates; this access
   modality guarantees authenticity, integrity and confidentiality
   of data.

6. PEC system client technical and functional prerequisites

   This section lists the prerequisites that must be respected by a
   client in order to guarantee the minimal operative functionalities
   to the user of a general PEC system:

   o handling of access and delivery points through secure channels;

   o handling of user authentication in message dispatch and reception
     phases;

   o support for MIME format according to [MIME1] and [MIME5];

   o handling of media type "message.rfc822";

   o support for "ISO-8859-1 (Latin-1)" character set;

   o support for S/MIME v3 standard, as in [SMIMEV3], for verification
     of signatures applied to envelopes and notifications.

7. Security Considerations

   All security considerations from [CMS] and [SMIMEV3] apply to
   applications that use procedures described in this document.

   The centralized LDAP server is a critical point for the security of
   the whole PEC system. An attack could compromise the whole PEC
   system. PEC providers that periodically download the LDIF file
   SHOULD use the best security technology to protect it from local
   attacks. A PEC provider could be compromised if an attacker changed
   a certificate or modified the list of domains associated





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   to it in the LDIF file that was copied to the PEC provider system.

   When verifying the validity of the signature of a message, the
   recipient system SHOULD verify that the certificate included in the
   [CMS] message is present in the LDIF file (section 4.5), and that
   the domain extracted by the [EMAIL] "From:" header is listed in the
   managedDomains attribute associated to said certificate.

8. IANA Considerations

   This document does not require any consideration from the IANA.

9. References

9.1. Normative References

   [CMS]     Housley, R., "Cryptographic Message Syntax (CMS)", RFC
             3852, Vigil Security, July 2004

   [EMAIL]   P. Resnick, Editor, "Internet Message Format", RFC 5322,
             QUALCOM Incorporated, April 2001

   [LDAP]    Legg, S., Editor, "Lightweight Directory Access Protocol
             (LDAP): Syntaxes and Matching Rules", RFC 4517, eB2Bcom,
             June 2006

   [LDIF]    Good, G., "The LDAP Data Interchange Format (LDIF) -
             Technical Specification", RFC 2849, iPlanet e-commerce
             Solutions, June 2000

   [MIME1]   Freed, N., and N. Borenstein, "Multipurpose Internet Mail
             Extensions (MIME) Part One: Format of Internet Message
             Bodies", RFC 2045, November 1996

   [MIME5]   Freed, N., and N. Borenstein, "Multipurpose Internet Mail
             Extensions (MIME) Part Five: Conformance Criteria and
             Examples", RFC 2049, November 1996

   [REQ]     Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, Harvard University,
             March 1997

   [SHA1]    Eastlake, D., and P. Jones, "US Secure Hash Algorithm 1
             (SHA1)", RFC 3174, September 2001






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   [MIME-SECURE] Galvin, J., S. Murphy, S. Crocker, and N. Freed,
                 "Security Multiparts for MIME: Multipart/Signed and
                 Multipart/Encrypted", RFC 1847, October 1995

   [SMIMEV3] Ramsdell, B. Editor, "Secure/Multipurpose Internet Mail
             Extensions (S/MIME) Version 3.1 Message Specifications",
             RFC 3851, Sendmail, Inc., July 2004

   [SMIMECERT]   Ramsdell, B., Editor, "Secure/Multipurpose internet
                 Mail Extensions (S/MIME) Version 3.1 Certificate
                 Handling", RFC 3850, Sendmail, Inc., July 2004

   [SMTP]    Klensin, J. Editor, "Simple Mail Transfer Protocol", RFC
             5321, AT&T Laboratories, April 2001

   [SMTP-DSN]    Moore, K., "Simple Mail Transfer Protocol (SMTP)
                 Service Extension for Delivery Status Notifications
                 (DSNs)", RFC 3461, University of Tennessee, January
                 2003

   [SMTP-TLS]    Hoffman, P., "SMTP Service Extension for Secure SMTP
                 over Transport Layer Security", RFC 3207, Internet
                 Mail Consortium, February 2002

   [TLS]     Dierks, T., and E.Rescorla, "The Transport Layer Security
             (TLS) Protocol Version 1.2", RFC 5246, August 2008

   [X509]    Cooper, D., S. Santesson, S. Farrell, S. Boeyen, R.
             Housley, and W. Polk, "Internet X.509 Public Key
             Infrastructure Certificate and Certificate Revocation
             List (CRL) Profile", RFC 5280, May 2008

10. Acknowledgments

   The Italian document, on which the present document is based, is
   a product of the collaboration of many, with the supervision of
   the National Center for Informatics in the Public Administration
   of Italy (CNIPA).












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APPENDIX A: Italian fields and values in English

   X-Riferimento-Message-ID        X-Reference-Message-ID
   X-Ricevuta                      X-Notification
     non-accettazione                non-acceptance
     accettazione                    acceptance
     preavviso-errore-consegna       advance-notice-delivery-error
     presa-in-carico                 take-charge
     rilevazione-virus               virus-detection
     errore-consegna                 delivery-error
     avvenuta-consegna               message-delivered
   X-VerificaSicurezza             X-SecurityVerification
   X-Trasporto                     X-Transport
     posta-certificata               certified-mail
     errore                          error
   X-VerificaSicurezza             X-SecurityVerification
     errore                          error
   X-TipoRicevuta                  X-NotificationType
     completa                        complete
     breve                           brief
     sintetica                       concise


   certificatore                   certificator


   Subject values:

     Accettazione                           ACCEPTANCE
     Posta certificata                      CERTIFIED MAIL
     Presa in carico                        TAKE IN CHARGE
     Consegna                               DELIVERY
     Anomalia messaggio                     MESSAGE ANOMALY
     Problema di sicurezza                  SECURITY PROBLEM
     Avviso di non accettazione             NON-ACCEPTANCE
                                            NOTIFICATION
     Avviso di non accettazione per virus   VIRUS DETECTION INDUCED
                                            NON-ACCEPTANCE NOTIFICATION
     Avviso di mancata consegna             NON-DELIVERY NOTIFICATION
     Avviso di mancata consegna per virus   NON-DELIVERY NOTIFICATION
                                            DUE TO VIRUS
     Avviso di mancata consegna per sup.    NON-DELIVERY NOTIFICATION
     tempo massimo                          DUE TO TIMEOUT







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Authors' Addresses

   Francesco Gennai
   ISTI-CNR
   Via Moruzzi, 1
   56126 Pisa
   Italy

   Email: francesco.gennai@isti.cnr.it


   Alba Shahin
   ISTI-CNR
   Via Moruzzi, 1
   56126 Pisa
   Italy

   Email: alba.shahin@isti.cnr.it


   Claudio Petrucci
   CNIPA
   Via Isonzo 21/B
   00198 Roma
   Italy

   Email: c.petrucci@cnipa.it

   Alessandro Vinciarelli
   CNIPA
   Via Isonzo 21/B
   00198 Roma
   Italy

   Email: alessandro.vinciarelli@cnipa.it


Copyright Statement

   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors. All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents in effect on the date of
   publication of this document (http://trustee.ietf.org/license-info).
   Please review these documents carefully, as they describe your
   rights and restrictions with respect to this document.




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Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.














































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