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Internet Draft                                             F. Gennai
Intended status: Standards track                           A. Shahin
Expires: April 2009                                         ISTI-CNR
                                                         C. Petrucci
                                                      A. Vinciarelli
                                                               CNIPA
                                                        October 2008



                     Certified Electronic Mail
                draft-gennai-smime-cnipa-pec-01.txt




Status of this Memo

  This memo provides information for the Internet community.  It
  does not specify an Internet standard of any kind. Distribution
  of this memo is unlimited.

  By submitting this Internet-Draft, each author represents that
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  becomes aware will be disclosed, in accordance with Section 6 of
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  This Internet-Draft will expire on April 2009.



Copyright Notice



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  Copyright (C) The IETF Trust (2008).



Abstract

  Since 1997, the Italian Laws have recognized electronic delivery
  systems as legally usable. After 2 years of technical tests, in
  2005 the characteristics of an official electronic delivery
  service, named certified electronic mail (in Italian "Posta
  Elettronica Certificata") were defined, giving the system legal
  value.

  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 ................................................ 4
  1.1. Scope ..................................................... 4
  1.2. Notational Conventions .................................... 5
  1.2.1. Requirement Conventions ................................. 5
  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 ...........................................14
  2.2.1. Access point ............................................14
  2.2.2. Incoming point ..........................................16
  2.2.3. Delivery point ..........................................18
  2.2.4. Storage .................................................19
  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


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  3.1.2. Non-acceptance notification due to one or more
         formal exceptions........................................21
  3.1.3. Non-acceptance notification due to virus detection.......22
  3.1.4. Acceptance notification .................................23
  3.1.5. Transport envelope ......................................23
  3.1.6. Timeout delivery error notification .....................25
  3.2. Incoming point ............................................27
  3.2.1. Take in charge notification .............................27
  3.2.2. Anomaly envelope ........................................28
  3.2.3. Virus detection notification ............................29
  3.2.4. Virus-induced delivery error notification................30
  3.3. Delivery point ............................................31
  3.3.1. Checks on incoming messages .............................31
  3.3.2. Delivery notification ...................................31
  3.3.3. Non-delivery notification ...............................36
  4. Formats .....................................................37
  4.1. Temporal reference ........................................37
  4.2. User date/time ............................................37
  4.3. Attachments ...............................................37
  4.3.1. Message body ............................................37
  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. Example: Complete transaction between 2 PEC domains..........48
  6. Security-related aspects ....................................49
  6.1. Digital signature .........................................49
  6.2. Authentication ............................................49
  6.3. Secure interaction ........................................50
  6.4. Virus .....................................................50
  6.5. S/MIME certificate ........................................51
  6.5.1. Provider-related information (subject) ..................51
  6.5.2. Certificate extensions ..................................51
  6.5.3. Example .................................................52
  6.6. PEC providers directory ...................................57
  7. PEC system client technical and functional prerequisites ....57
  8. Security Considerations .....................................57
  9. IANA Considerations .........................................58
  10. References .................................................58
  10.1. Normative References .....................................58
  11. Acknowledgments ............................................59
  APPENDIX A: Italian fields and values in English ...............60
  Author's Addresses .............................................61
  Intellectual Property Statement ................................61
  Disclaimer of Validity .........................................62




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1. Introduction

  Since 1997, the Italian Laws have recognized electronic delivery
  systems as legally usable. After 2 years of technical tests, in
  2005 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 value.

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. But, even though end-
  to-end cryptography offers a high level of security, it has a
  downside; the need for an extensive penetration of technology in
  the society, since it would be essential for every user to have
  a couple of symmetric keys and a certificate, signed by a
  Certification Authority, associated with the public key. Along
  with that, users would need to have an adequate amount of
  knowledge regarding the use of such technology.

  PEC on the other hand offers the digital signing of messages
  through applications running directly on the servers, 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 Regulations and
  functionality. It presents the details of the protocol and the
  messages that are sent between service providers. It is meant to
  be an introduction to the system the Italian government has
  adopted for the sending and receiving of certified emails,
  giving them a legal value equivalent to that of Registered Mail
  with Return Receipt.




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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].

1.2.2. Acronyms

  CMS:      Cryptographic Message Syntax
  CNIPA:    National Center for Informatics in the Public
            Administration of Italy (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 go smoothly, 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


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  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.

  Anomaly envelope: When a message contains errors or is not a PEC
  message it MUST be 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 include: 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.


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  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.

  Holder: The person 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 go smoothly, 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 reception 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.



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  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:

  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 incoming 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. Within a PEC domain, all PEC mailboxes MUST
  belong to holders. PEC messages MUST be elaborated even if both
  sender and recipient belong to the same PEC domain.

  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.





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  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.

  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;


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  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.

  In order for the receiving mail client to be able to verify the
  signature, the sender address must coincide with the one
  indicated within the X.509v3 certificate. This mechanism
  requires transport envelopes to 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>

  It is necessary for the "Reply-To:" field to contain a correct
  value in the transport envelope, so replies can be correctly
  sent back to the proper destination. When such a field is not
  explicitly specified in the original message, the system that
  generates the transport envelope sees to its creation by
  extracting the information from the "From:" field in the
  original message. If on the other hand that field is specified
  in the original message, it MUST NOT be altered.

  When notifications need to be sent, the system uses as
  destination address that of the original message's sender only,
  exactly 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.



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  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.

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.



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  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 concern 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.

  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"


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  (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.

  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.




















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2.2. Basic structure

            +-------------+               +------------+
            |    +--+     |               |            |
            |    |AP|     |               |            |
  +----+    |    +--+     |   messages&   | +--+ +---+ |    +----+
  |user|<-->|             |<------------->| |DP| |InP| |<-->|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 is then to receive
  the original messages its user wishes to send, run some formal
  checks, and act according to the outcome:

  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 some 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 a 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-


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  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]>

  In case the 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 existent, the msgid is REQUIRED to be
  provided 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).



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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
  circuit 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 can be handled using the
  standard error notification mechanisms, as provided by SMTP in
  [SMTP] and [SMTP-DSN]. The same mechanism is also adapted for
  handling transitory errors, that result in long idling periods,
  during an SMTP transmission phase. In order to guarantee the
  emission of a signal to the user when an error occurs,
  coherently with the modalities defined in section 3.3.3, the
  systems that handle 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 nature 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).

  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, therefore passes
    the verifications regarding existence, origin, and signature
    validity, then the message MUST be propagated towards the
    recipient. Therefore, the incoming point:




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     - 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,
    therefore fails verifications regarding existence, origin and
    signature validity, 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 was emitted by a PEC provider. So, the incoming
    point extracts the certificate used for signing the incoming
    message and verifies its presence in the PEC providers
    directory. To facilitate the check, it is possible to
    calculate the extracted 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 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 algorithm 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;


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  o Formal correctness - the provider performs sufficient and
    necessary checks to guarantee formal correctness aspects
    which are necessary for interoperability.

  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 a 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 circuit.
  If a virus is detected in an ordinary mail message, the latter
  can be discarded at the incoming point before it enters the PEC
  circuit. 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.

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. 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:



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        X-Trasporto: posta-certificata

  In all other cases, such as anomaly envelopes and notifications,
  the delivery notification is not emitted. In any case, 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 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.

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


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  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 that data and preserve it for 30
  months.

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.



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  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:

     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 its
  automatic elaboration (section 4.4). Other attachments MAY BE
  added to the notification message to follow certain functional



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  specifications supplied by the provider, but the original
  message MUST NOT in any case be inserted.

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:

     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 elaboration (section
  4.4). The notification MAY contain other attachments relevant to


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  specific functionalities supplied by the provider, though the
  original message MUST NOT in any case 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]

  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 its
  automatic elaboration (section 4.4). Other attachments MAY BE
  added to the notification message to follow certain functional
  specifications supplied by the provider.

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.




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  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 will HAVE TO be
  modified, or inserted if necessary:

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



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     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 elaborate, 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). Other elements MAY BE added to the
  transport envelope for functionalities supplied by the PEC
  provider.

  Even if the "From:" field of the transport envelope is modified
  to allow for the verification of the signature by the recipient,
  routing data of the transport envelope (forward and reverse
  paths) remain unchanged with respect to the same data of the
  original message.

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 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:



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     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 will 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
     negative outcome.
     Massage identification: [Message-ID]

  The same certification data is inserted in an XML file to be
  attached to both notification types to allow an automatic
  elaboration (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
  in any case 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.






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  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 neither 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:

     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:


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     [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
  elaboration (section 4.4). The notification MAY also contain
  other attachments relevant to specific functionalities supplied
  by the provider.

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 inserts 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 HAS TO inherit the values for the following header fields
  unmodified from the message received:

  o Received

  o To

  o Cc

  o Return-Path

  o Message-ID

  Whereas, the following header fields will HAVE TO 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)]



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  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
  reception point.

  Even though the "From:" field of the anomaly envelope is
  modified for signature verification purposes, routing data of
  such an envelope (forward and reverse paths) remain unchanged
  with respect to the same data present in the message received.
  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]).

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
  impossibility to go through with the transmission. A separate
  notification of virus detection will HAVE to 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, to be sent to the
  sending provider's service mailbox.

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


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     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 elaboration
  (section 4.4). The notification MAY contain other attachments
  relevant to specific functionalities supplied by the provider;
  however, it MUST NOT contain the original message.

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

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:


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     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
  elaboration (section 4.4). The notification message MAY contain
  other attachments relevant to specific functionalities supplied
  by the provider. The reason for which the transaction was
  impossible to complete 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 its type and determines whether or not a notification
  should be emitted to the sender.

3.3.2. Delivery notification

  A delivery notification is issued after the received message has
  been delivered to the recipient's mailbox, and only upon the
  reception of a correct PEC transport envelope. The latter can be
  easily identifiable for 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. In any case, the message
  received at the delivery point MUST be delivered to the
  recipient's mailbox unchanged.




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  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 format of the delivery notifications
  relative to 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 receiving in carbon copy is done through an
  analysis of the "To:" and "Cc:" fields of the message with
  respect to the delivery addressee. Exclusively in notifications
  sent on behalf of primary recipients, along with the attachments
  already described, a complete copy of the original message is
  inserted. 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 will HAVE TO 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]"


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     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 to be
  attached to the notification (section 4.4), along with any other
  attachments that MAY be inserted for specific functionalities
  supplied by the provider. 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, with all attachments, if present, substituted with
  their respective ciphered hash values. To be able to verify the
  transmitted contents, it is necessary for the sender to keep the
  original copy of the attachment(s), to which the hash values
  refer, unchanged.

  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:

     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



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  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, which would
  result in modifying the MIME parts of the S/MIME construction.
  Verification of the S/MIME nature 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-signature"

  The message is composed of a sole CMS object within the MIME
  part. Given the impossibility to distinguish attachments, if
  present within the CMS object, the MIME part is left intact
  without being substituted by the respective hash value, thus
  determining the emission of a brief delivery notification with
  the same contents of a normal delivery notification.

  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:



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  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

  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:


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     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 to be
  attached to the notification (section 4.4), along with other
  optional attachments specific to provider-supplied
  functionalities. 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, and not the
  original message.

3.3.3. Non-delivery notification

  If an error occurs during the delivery of a correct PEC
  transport message, the system generates a notification for non-
  delivery to be sent to the sender, with indication of the error.

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

  The same certification data is inserted within an XML files
  added to the notification in order to allow for a an automatic


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  elaboration (section 4.4). The notification MAY contain other
  attachments for specific functionalities supplied by the PEC
  provider.

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
  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




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  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. The HTML part will HAVE TO respect the
  following conditions:

  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-->
  <!--"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-->


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



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

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




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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 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


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  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.

  - 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]:



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  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'
          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'


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          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

  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::


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   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
  managedDomains: cert.company.it
  managedDomains: costmec.it
  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
   ygWxYXLBZNfSDWqL1K4edLr4gCZIDFsq0PIEaYZhYRGjhbcuJ9H/ZdtWdX
   xcwEWN4mwFzlsASogsh5JeqS8db3A1JWkvhO9EUfaCYk8YMAkXYdCtLD9s
   9tCYZeTE2ut9AgMBAAGjgcswgcgwHQYDVR0OBBYEFHPw7VJIoIM3VYhuHa
   eAwpPF5leMMIGYBgNVHSMEgZAwgY2AFHPw7VJIoIM3VYhuHaeAwpPF5leM
   oXKkcDBuMQswCQYDVQQGEwJJVDEfMB0GA1UEChMWU2Vydml6aSBQb3N0YW
   xpIFMuci5sLjEPMA0GA1UECxMGRC5DLkMuMS0wKwYJKoZIhvcNAQkBFh5w
   b3N0YS1jZXJ0aWZpY2F0YUBzZXJwb3N0YWwuaXSCAQAwDAYDVR0TBAUwAw


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   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
   alZelqrwqmElna4MNUaLhbOvTd/sqPUS378w5IaIhWxzy34XcCAwEAAaOB
   wzCBwDAdBgNVHQ4EFgQUN8lC0znQWEs0xspZ/aBzsaGvRZMwgZAGA1UdIw
   SBiDCBhYAUN8lC0znQWEs0xspZ/aBzsaGvRZOhaqRoMGYxCzAJBgNVBAYT
   AklUMSkwJwYDVQQKEyBBbm9uaW1hIFBvc3RhIENlcnRpZmljYXRhIFMucC
   5BLjEsMCoGCSqGSIb3DQEJARYdcG9zdGEtY2VydGlmaWNhdGFAYW5wb2Nl
   cnQuaXSCAQAwDAYDVR0TBAUwAwEB/zANBgkqhkiG9w0BAQQFAAOBgQA58B
   Z+q1qSKpuffzTBpMtbeFkDIxMqMa+ycnxdMNvcWgCm1A9ZiFJsvqYhDDqA


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   XxfHjkrzXuSZkYq6WiQCsLp0aYVy40QCIwbOunhrvsxh3vsG5CgN76JzZ9
   5Z/1OCFNhLfqf1VH2NSS8TaYCCi/VO7W1Q1KkcA2VlxlQP7McSUw==
  mailReceipt: notifications@anpocert.it
  LDIFLocationURL: http://www.anpocert.it/LDIF/anpocert.ldif.p7m
  managedDomains: mail.anpocert.it
  managedDomains: cert.company.it
  managedDomains: costmec.it
  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
  managedDomains: personnel.anpocert.it
  description: Corporate internal services

  dn: providerName=Postal Services S.r.l.,o=postacert
  objectclass: top
  objectclass: provider
  providerName: Postal Services S.r.l.
  providerCertificateHash:
   e00fdd9d88be0e2cc766b893315caf93d5701a6a


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  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. Example: Complete transaction between 2 PEC domains

  A correct transaction between 2 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;


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  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;

  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.

6. Security-related aspects

6.1. Digital signature

  The private key and signature operations MUST be handled using a
  dedicated hardware security module (FIPS 140-2) which is able to
  guarantee their security in compliance with the criteria adopted
  in the European or international setting.

6.2. Authentication

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






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6.3. 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.

6.4. 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.




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6.5. 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.

6.5.1. 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].

6.5.2. Certificate extensions

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

  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.


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  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.

6.5.3. 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.

6.5.3.1. 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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6.5.3.2. 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 ]
      :   }

6.6. PEC providers directory

  The contents of the PEC providers directory can be queried via
  HTTP on SSL exclusively by licensed providers that have the
  necessary user certificates; this access modality guarantees
  authenticity, integrity and discretion of data.

7. 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.

8. 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



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  associated 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.

  A Hardware Security Module compliant with the FIPS-140-2 is
  REQUIRED to store the private key of each PEC provider.

9. IANA Considerations

  This document does not require any consideration from the IANA.




10. References

10.1. 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 4516, 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





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  [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

  [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

  [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

11. 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. tempo massimo
                                            NON-DELIVERY
                                            NOTIFICATION
                                            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


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