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WG TLS                                               Jens Guballa (ed.)
Internet Draft                                 Juergen Stoetzer-Bradler
Intended status: Informational                                    Nokia
Expires: April 2017                                             He Bing
                                           Alcatel-Lucent Shanghai Bell
                                                        October 4, 2016


                    Terminology related to TLS and DTLS
                   draft-guballa-tls-terminology-05.txt






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   This Internet-Draft will expire on March 4, 2017.

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors. All rights reserved.

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

Abstract

   Purpose of this RFC is to provide a central place of all key terms
   as used by the various RFCs on protocols TLS and DTLS.

Table of Contents

   1. Introduction...................................................4
      1.1. Background and motivation - Status of (D)TLS terminology..4
      1.2. Purpose...................................................4
      1.3. Scope.....................................................4
      1.4. Relation with Internet Security Glossary..................4
      1.5. Disclaimer................................................5
   2. Conventions used in this document..............................5
      2.1. Prescriptive language: modal verbs........................5
      2.2. Notion of '(D)TLS'........................................5
      2.3. Additional terminology....................................5
      2.4. Abbreviations used........................................5
   3. Inventory of (D)TLS terms......................................6
      3.1. Terminology related to endpoint entities..................6
         3.1.1. Term "(D)TLS endpoint"...............................6
         3.1.2. Term "(D)TLS protocol implementation"................6
      3.2. Terminology related to session/connection entities........7
         3.2.1. Term "(D)TLS connection".............................7
         3.2.2. Term "Semi-permannt (D)TLS session"..................7
         3.2.3. Term "Transient (D)TLS session"......................8
         3.2.4. Term "(D)TLS session"................................8
         3.2.5. Term "DTLS association"..............................9
      3.3. Terminology related to session/connection endpoint entities
      ..............................................................10
         3.3.1. Term "(D)TLS connection endpoint"...................10
         3.3.2. Term "(D)TLS connection endpoint identifier"........10
         3.3.3. Term "(D)TLS client connection endpoint"............11


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         3.3.4. Term "(D)TLS server connection endpoint"............11
      3.4. Terminology related to protocol procedures...............12
         3.4.1. Term "(D)TLS message"...............................12
         3.4.2. Term "(D)TLS client role"...........................12
         3.4.3. Term "(D)TLS server role"...........................13
         3.4.4. Term "(D)TLS message sequence"......................13
         3.4.5. Term "(D)TLS full handshake"........................13
         3.4.6. Term "(D)TLS abbreviated handshake".................14
         3.4.7. Term "Data transfer ready (D)TLS connection"........14
         3.4.8. Term "Semi-permanent (D)TLS client session endpoint
         state".....................................................15
         3.4.9. Term "Semi-permanent (D)TLS server session endpoint
         state".....................................................15
         3.4.10. Term "Transient (D)TLS client session endpoint state"
         ...........................................................15
         3.4.11. Term "Transient (D)TLS server session endpoint state"
         ...........................................................16
         3.4.12. Term "(D)TLS client session endpoint state"........16
         3.4.13. Term "(D)TLS server session endpoint state"........18
         3.4.14. Term "Resumable (D)TLS client session endpoint state"
         ...........................................................19
         3.4.15. Term "Resumable (D)TLS server session endpoint state"
         ...........................................................20
         3.4.16. Term "Resumable (D)TLS session"....................20
         3.4.17. Term "Resumed (D)TLS session"......................21
         3.4.18. Term "(D)TLS session resumption"...................22
         3.4.19. Term "(D)TLS session identifier"...................23
      3.5. Colloquially used terms..................................23
         3.5.1. Term "(D)TLS session re-establishment"..............23
         3.5.2. Term "(D)TLS session rekeying"......................24
         3.5.3. Term "(D)TLS rehandshake"...........................24
   4. Security Considerations.......................................25
   5. IANA Considerations...........................................25
   6. References....................................................25
      6.1. Normative References.....................................25
      6.2. Informative References...................................25
   7. CHANGE LOG....................................................26
      7.1. Initial draft name "draft-guballa-tls-terminology".......26
         7.1.1. Version "-00".......................................26
         7.1.2. Changes against "-00"...............................26
         7.1.3. Changes against "-01"...............................27
         7.1.4. Changes against "-02"...............................27
         7.1.5. Changes against "-03"...............................27
   Appendix A. Hierarchical Framework...............................28
      A.1. Framework for (D)TLS Connection related Definitions......29
      A.2. Framework for (D)TLS Session related Terms...............30



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      A.3. Framework for (D)TLS Session Resumption and (D)TLS Session
      renegotiation.................................................31


1. Introduction

1.1. Background and motivation - Status of (D)TLS terminology

   The definition of the TLS protocol [RFC5246] is slightly unusual in
   the area of protocol specifications, because more like a software
   description with a high-level data model, perhaps written after an
   implementation.  The RFC does not provide explicit definitions for
   the main terms, rather providing a glossary in Appendix B/[RFC5246].
   The Glossary itself provides descriptions of the main terms, but not
   any definitions.  At least not definitions at the detailed level as
   required for protocol specifications, which implies a precise
   linkage to objects as e.g. used within protocol and service data
   units and protocol control information elements.

   E.g., there are concerns and ongoing debates about the semantics of
   some "handshake" related protocol procedures (catchwords "re-
   establishment", "resumption", "renegotiation", "rekeying").
   Associated to these procedural aspects is the underlying question
   concerning the precise distinction between (D)TLS session and (D)TLS
   connection level.

   Without any doubt, TLS itself is a pretty successful, mature and
   well-proven technology.  The production of (D)TLS term definition
   implies hence reverse engineering of (D)TLS RFCs.

1.2. Purpose

   The purpose of this document is to provide a central place of key
   terms as used in TLS and DTLS RFCs.  The definitions should be
   concise, but detailed enough from perspective of a protocol model,
   and of course fully consistent and compatible with the existing
   RFCs.

1.3. Scope

   The focus is put on key terms which caused some controversy so far.

1.4. Relation with Internet Security Glossary

   The Internet Security Glossary [RFC4949] provides a comprehensive
   set of security related terms.  However, protocol specific terms



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   such as for DTLS and TLS are not part of the glossary.  Hence, there
   is actually not any overlapping between this document and [RFC4949].

1.5. Disclaimer

   Where there are discrepancies between this document and existing
   RFCs on TLS and DTLS, the usage and "semantics" of these (D)TLS RFCs
   take precedence over those described in this document.

2. Conventions used in this document

2.1. Prescriptive language: modal verbs

   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 RFC-2119 [RFC2119].

2.2. Notion of '(D)TLS'

   The prefix '(D)TLS' indicate terms common to both protocols.  The
   prefixes 'TLS' and 'DTLS' indicate protocol specific aspects.

2.3. Additional terminology

   <term>:

     <definition>

2.4. Abbreviations used

   AL       Local (IP) Address

   AR       Remote (IP) Address

   DTLS     Datagram Transport Layer Security

   (D)TLS   DTLS or TLS

   FQDN     Fully Qualified Domain Name

   L4       (Protocol) Layer 4 (= IP Transport layer)

   PL       Local (L4) Port

   PR       Remote (L4) Port

   RL       Record Layer


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   T        Transport (L4) protocol

   TCP      Transmission Control Protocol

   TLS      Transport Layer Security

   UDP      User Datagram Protocol

3. Inventory of (D)TLS terms



3.1. Terminology related to endpoint entities

3.1.1. Term "(D)TLS endpoint"

   Definition:

     An instance of a (D)TLS protocol implementation with exactly one
     local IP (transport) address.  A (D)TLS endpoint is housing one or
     multiple (D)TLS connection endpoints, which are acting either as
     (D)TLS clients or as (D)TLS servers (i.e., "(D)TLS client
     connection endpoint" and "(D)TLS server connection endpoint") when
     executing the (D)TLS handshake protocol.

   Reference:

     None.

   Term relations:

     Definition based on terms "(D)TLS protocol implementation" (3.1.2.
     ), "(D)TLS client connection endpoint" (3.3.3. ), and "(D)TLS
     server connection endpoint" (3.3.4. ).

3.1.2. Term "(D)TLS protocol implementation"

   Definition:

     A (software or hardware) based implementation of the TLS protocol
     as specified in [RFC5246] or of the DTLS protocol as specified in
     [RFC6347] (DTLS) and is always associated to a real system.

   Reference:

     [RFC5246] and [RFC6347].



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   Term relations:

     Definition based on term "real system" [ITU-T X.200].



3.2. Terminology related to session/connection entities

3.2.1. Term "(D)TLS connection"

   Definition:

     A cooperative relationship among a pair of (D)TLS capable systems,
     represented by a (D)TLS client connection endpoint and a (D)TLS
     server connection endpoint (NOTE 1).  A (D)TLS connection allows
     the execution of an establishment procedure given by either a
     (D)TLS full handshake or a (D)TLS abbreviated handshake (on
     request of the (D)TLS served user instance at (D)TLS client side).
     Thus, the mode of communication of the (D)TLS connection could be
     considered as connection-oriented (i.e., a (D)TLS connection is
     stateful, e.g., at the top-level by the 2-state model {IDLE,
     ESTABLISHED}).

   Notes:

     Thus, formally the (D)TLS connection is a set of two 8-tuples,
     refer to "(D)TLS connection endpoint".

   Reference:

     The term "connection" is part of the glossary of [RFC5246].

   Term relations:

     Definition based on terms "(D)TLS protocol implementation" (3.1.2.
     ), "(D)TLS client connection endpoint" (3.3.3. ), and "(D)TLS
     server connection endpoint" (3.3.4. ).

3.2.2. Term "Semi-permannt (D)TLS session"

   Definition:

     The pair of a semi-permanent (D)TLS client session endpoint state
     and a semi-permanent (D)TLS server session endpoint state, coupled
     by the (D)TLS full handshake procedure which was executed across
     the associated (D)TLS connection.



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   Reference:

     None.

   Term relations:

     Definition based on terms "semi-permanent (D)TLS client session
     endpoint state" (3.4.8. ), "semi-permanent (D)TLS server session
     endpoint state" (3.4.9. ), "(D)TLS full handshake" (3.4.5. ), and
     "(D)TLS connection" (3.2.1. ).

3.2.3. Term "Transient (D)TLS session"

   Definition:

     The pair of a transient (D)TLS client session endpoint state and a
     transient (D)TLS server session endpoint state, coupled by the
     (D)TLS full handshake procedure which was executed across the
     associated (D)TLS connection.

     The transient (D)TLS client session endpoint state information and
     transient (D)TLS server session endpoint state information is
     immediately deleted after the successful (D)TLS full handshake
     procedure.

   Reference:

     None.

   Term relations:

     Definition based on terms "transient (D)TLS client session
     endpoint state" (3.4.10. ), "transient (D)TLS server session
     endpoint state" (3.4.11. ), "(D)TLS full handshake" (3.4.5. ), and
     "(D)TLS connection" (3.2.1. ).

3.2.4. Term "(D)TLS session"

   Definition:

     A semi-permanent (D)TLS session or transient (D)TLS session.

   Notes:

     Thus, a (D)TLS session is a transformed (D)TLS connection after
     the successful execution of a (D)TLS full handshake procedure,
     constituted by the pair of (D)TLS client session endpoint state


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     and a (D)TLS server session endpoint state.  A (D)TLS session is
     consequently an association between the two (D)TLS session
     endpoints.  The mode of communication of the (D)TLS session could
     be considered as connectionless (i.e., a (D)TLS session is either
     existing or not).

     The nature of a (D)TLS session (from (D)TLS endpoint perspective)
     is either volatile (i.e., the local (D)TLS session information
     would be immediately discarded after a (D)TLS handshake procedure)
     or semi-permanent (in case of resumable (D)TLS sessions).

     Notably, a (D)TLS session may still exist after one or even both
     (D)TLS connection endpoints, which did exchange the (D)TLS full
     handshake messages from which the related (D)TLS session states
     were derived from, are already destroyed.

     The (D)TLS role (client or server) is a (D)TLS session level
     characteristic. (to be confirmed)

   Reference:

     The term "session" is part of the glossary of [RFC5246].

   Term relations:

     Definition based on terms "(D)TLS semi-permanent session" (3.2.2.
     ), and "(D)TLS transient (volatile) session" (3.2.3. ).

3.2.5. Term "DTLS association"

   Definition:

     Synonym to "DTLS connection".

   Reference:

     Term introduced by [RFC4347] and still used in [RFC6347].

   Term relations:

     Definition equal to "(D)TLS connection" (3.2.1. ).








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3.3. Terminology related to session/connection endpoint entities

3.3.1. Term "(D)TLS connection endpoint"

   Definition:

     A part of an instance of a (D)TLS protocol implementation, which
     is able to send and receive (D)TLS messages, and which is
     associated to exactly one 8-tuple being composed of

     1)  a creation point in time tc,

     2)  a destruction point in time td,

     3)  a non-empty local IP address AL,

     4)  a non-empty local L4 port PL,

     5)  an empty or non-empty remote IP address AR,

     6)  an empty or non-empty remote L4 port PR,

     7)  a non-empty L4 transport protocol T, and

     8)  the protocol string "TLS" or "DTLS".

   Notes:

     If FQDNs are used as (D)TLS endpoint identifiers, then an
     additional requirement on the (D)TLS connection endpoint could be
     that AL is one of the IP addresses associated to the (D)TLS
     endpoint's FQDN.

   Reference:

     [RFC5246], [RFC5764]

   Term relations:

     Definition based on terms "(D)TLS protocol implementation" (3.1.2.
     ) and "(D)TLS message" (3.4.1. ).

3.3.2. Term "(D)TLS connection endpoint identifier"

   Definition:




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     The local IP transport address and indication of "TLS/L4" or
     "DTLS/L4" protocol stack, i.e., the 4-tuple of {AL, PL, T,
     "TLS"/"DTLS"} from the (D)TLS connection endpoint.

   Notes:

     Parameter "L4" is required because (D)TLS is a L4 independent
     protocol, hence a (D)TLS capable system could offer multiple
     (D)TLS endpoints with different L4 protocols.

   Reference:

     None.

   Term relations:

     Definition based on terms "(D)TLS protocol implementation" (3.1.2.
     ) and "(D)TLS message" (3.4.1. ).

3.3.3. Term "(D)TLS client connection endpoint"

   Definition:

     A (D)TLS connection endpoint which sends a (D)TLS message
     containing a ClientHello handshake structure to another (D)TLS
     connection endpoint.

   Reference:

     The TLS ClientHello handshake structure is defined in [RFC5246]
     while the DTLS ClientHello handshake structure is defined in
     [RFC6347].

   Term relations:

     Definition based on terms "(D)TLS connection endpoint" (3.3.1. )
     and "(D)TLS message" (3.4.1. ).

3.3.4. Term "(D)TLS server connection endpoint"

   Definition:

     A (D)TLS connection endpoint which receives a (D)TLS message
     containing a ClientHello handshake structure and subsequently
     sends a (D)TLS message containing a ServerHello handshake
     structure back to that other (D)TLS connection endpoint.



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   Reference:

     The (D)TLS ServerHello handshake structure is defined in
     [RFC5246].

   Term relations:

     Definition based on terms "(D)TLS connection endpoint" (3.3.1. )
     and "(D)TLS message" (3.4.1. ).



3.4. Terminology related to protocol procedures

3.4.1. Term "(D)TLS message"

   Definition:

     A unit of (D)TLS-RL user data as produced by the (D)TLS handshake
     protocol, the (D)TLS alert protocol or the (D)TLS change cipher
     spec protocol.

   Notes:

     Application Data are excluded from this definition.

   Reference:

     Clause 6.2.1 of [RFC5246] defines the message type as an
     enumeration ("ContentType"). It is contained in the structured
     type "TLSPlaintext".Term relations:



3.4.2. Term "(D)TLS client role"

   Definition:

     A (D)TLS connection endpoint is said to assume the (D)TLS client
     role, if it is a (D)TLS client connection endpoint.

   Reference:

     The term "client" is part of the glossary of [RFC5246].

   Term relations:



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     Definition based on terms "(D)TLS connection endpoint" (3.3.1. )
     and "(D)TLS client connection endpoint" (3.3.3. ).

3.4.3. Term "(D)TLS server role"

   Definition:

     A (D)TLS connection endpoint is said to assume the (D)TLS server
     role, if it is a (D)TLS server connection endpoint.

   Reference:

     The term "server" is part of the glossary of [RFC5246].

   Term relations:

     Definition based on terms "(D)TLS connection endpoint" (3.3.1. )
     and "(D)TLS server connection endpoint" (3.3.4. ).

3.4.4. Term "(D)TLS message sequence"

   Definition:

     A finite sequence of (D)TLS messages.

   Reference:

     None.

   Term relations:

     Definition based on term "(D)TLS message" (3.4.1. ).

3.4.5. Term "(D)TLS full handshake"

   Definition:

     A (D)TLS message sequence where the first (D)TLS message contains
     ClientHello structure and if the sequence constitutes a successful
     (D)TLS full handshake message flow as specified in clause 7.3,
     Figure 1 of [RFC5246].

   Reference:

     A full TLS handshake is presented in [RFC5246], clause 7.3, Figure
     1.  The DTLS' specifics are presented in [RFC6347], clause 4.2.1.



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   Term relations:

     Definition based on term "(D)TLS message" (3.4.1. ).

3.4.6. Term "(D)TLS abbreviated handshake"

   Definition:

     A (D)TLS message sequence where the first (D)TLS message contains
     ClientHello structure and if the sequence constitutes a successful
     (D)TLS abbreviated handshake message flow as specified in clause
     7.3, Figure 2 of [RFC5246].

   Reference:

     An abbreviated TLS handshake is presented in [RFC5246], clause
     7.3, Figure 2.  The DTLS' specifics are presented in [RFC6347],
     clause 4.2.1.

   Term relations:

     Definition based on term "(D)TLS message" (3.4.1. ).

3.4.7. Term "Data transfer ready (D)TLS connection"

   Definition:

     A (D)TLS connection after the successful execution of a (D)TLS
     full handshake or a (D)TLS abbreviated handshake procedure.

   Notes:

     The notion of "DATA TRANSFER READY" refers to a specific state of
     the (D)TLS connection and is synonym to the notion of
     "ESTABLISHED".  The general term "DATA TRANSFER READY" matches
     both connectionless and connection-oriented type of connections,
     see [ITU-T X.213 and X.214].

   Reference:

     None.

   Term relations:

     Definition based on terms "(D)TLS connection" (3.2.1. ), "(D)TLS
     full handshake" (3.4.5. ) and "(D)TLS abbreviated handshake"
     (3.4.6. ).


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3.4.8. Term "Semi-permanent (D)TLS client session endpoint state"

   Definition:

     A (D)TLS client session endpoint state if its (D)TLS session
     identifier value is non-empty.

   Reference:

     The term "session identifier" is part of the glossary of
     [RFC5246].

   Term relations:

     Refer to "(D)TLS client session endpoint state" (3.4.12. ) and
     "(D)TLS session identifier" (3.4.19.

3.4.9. Term "Semi-permanent (D)TLS server session endpoint state"

   Definition:

     A (D)TLS server session endpoint state if its (D)TLS session
     identifier value is non-empty.

   Reference:

     The term "session identifier" is part of the glossary of
     [RFC5246].

   Term relations:

     Refer to "(D)TLS server session endpoint state" (3.4.13. ) and
     "(D)TLS session identifier" (3.4.19.

3.4.10. Term "Transient (D)TLS client session endpoint state"

   Definition:

     A (D)TLS client session endpoint state if its (D)TLS session
     identifier value is empty.

   Reference:

     The term "session identifier" is part of the glossary of
     [RFC5246].

   Term relations:


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     Refer to "(D)TLS client session endpoint state" (3.4.12. ) and
     "(D)TLS session identifier" (3.4.19.

3.4.11. Term "Transient (D)TLS server session endpoint state"

   Definition:

     A (D)TLS server session endpoint state if its (D)TLS session
     identifier value is empty.

   Reference:

     The term "session identifier" is part of the glossary of
     [RFC5246].

   Term relations:

     Refer to "(D)TLS server session endpoint state" (3.4.13. 3.4.12. )
     and "(D)TLS session identifier" (3.4.19.



3.4.12. Term "(D)TLS client session endpoint state"

   Definition:

     The 17-tuple of following parameter-value pairs, as partially
     described in [RFC5246]:

     TLS protocol parameter:    Type:

     1.  version:               ProtocolVersion

     2.  prf_algorithm:         PRFAlgorithm

     3.  bulk_cipher_algorithm: BulkCipherAlgorithm

     4.  cipher_type:           CipherType

     5.  enc_key_length:        uint8

     6.  block_length:          unit8

     7.  fixed_iv_length:       unit8

     8.  record_iv_length:      unit8



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     9.  mac_algorithm:         MACAlgorithm

     10. mac_length:            unit8

     11. mac_key_length:        unit8

     12. compression_algorithm: CompressionMethod

     13. master_secret:         opaque[48]

     14. session_id:            SessionID (NOTE 1)

     Other parameters:          Type:

     15. creation time tc:      time (NOTE 2)

     16. destruction time td:   time

     17. server_address:        IPaddress (NOTE 3)



   Notes:

     1: A (D)TLS client session endpoint state is semi-permanent if and
     only if its session_id value is non-empty.  Hence it is transient
     if and only if its session_id value is empty.

     FIX THIS: Session tickets [RFC5077] must be covered as well,
     reference to "(D)TLS session identifier" should be used.2: While a
     semi-permanent (D)TLS client session endpoint state's creation
     point in time correlates with the corresponding (D)TLS full
     handshake's end time (which is thus a point in time at which both
     TLS connection endpoints, which exchange the (D)TLS full handshake
     messages, do still exist), this semi-permanent (D)TLS client
     session endpoint state's destruction point in time is independent
     of the destruction points in time of these two (D)TLS connection
     endpoints.  Especially, the semi-permanent (D)TLS client session
     endpoint state may still exist after one or even both (D)TLS
     connection endpoints are already destroyed.

     3: A (D)TLS protocol implementation may add further information to
     a (D)TLS client session endpoint state, like e.g. the associated
     (D)TLS server endpoint's source IP address.  This additional
     information may be used by a (D)TLS client connection endpoint in
     order to decide if an already stored semi-permanent (D)TLS client
     session endpoint state may be used (may be "resumed") for the


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     establishment of a new (D)TLS connection towards a destination
     transport address of another (D)TLS endpoint.

   Reference:

     The definition of this term is based on the structured type
     "SecurityParameters" as defined in clause 6.1 of [RFC5246].

   Term relations:

     -

3.4.13. Term "(D)TLS server session endpoint state"

   Definition:

     The 16-tuple of following parameter-value pairs, as partially
     described in [RFC5246]:

     TLS protocol parameter:    Type:

     1.  version:               ProtocolVersion

     2.  prf_algorithm:         PRFAlgorithm

     3.  bulk_cipher_algorithm: BulkCipherAlgorithm

     4.  cipher_type:           CipherType

     5.  enc_key_length:        uint8

     6.  block_length:          unit8

     7.  fixed_iv_length:       unit8

     8.  record_iv_length:      unit8

     9.  mac_algorithm:         MACAlgorithm

     10. mac_length:            unit8

     11. mac_key_length:        unit8

     12. compression_algorithm: CompressionMethod

     13. master_secret:         opaque[48]



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     14. session_id:            SessionID (NOTE 1)

     Other parameters (NOTE 3): Type:

     15. creation time tc:      time (NOTE 2)

     16. destruction time td:   time

   Notes:

     1: A (D)TLS server session endpoint state is semi-permanent if and
     only if its session_id value is non-empty.  Hence it is transient
     if and only if its session_id value is empty.

     FIX THIS: Session tickets [RFC5077] must be covered as well,
     reference to "(D)TLS session identifier" should be used.

     2: While a semi-permanent (D)TLS server session endpoint state's
     creation point in time correlates with the corresponding (D)TLS
     full handshake's end time (which is thus a point in time at which
     both (D)TLS connection endpoints, which exchange the (D)TLS full
     handshake messages, do still exist), this semi-permanent (D)TLS
     server session endpoint state's destruction point in time is
     independent of the destruction points in time of these two (D)TLS
     connection endpoints.  Especially, the semi-permanent (D)TLS
     server session endpoint state may still exist after one or even
     both (D)TLS connection endpoints are already destroyed.

     3: Difference between the (D)TLS server session endpoint state
     versus the (D)TLS server session endpoint: the 17th parameter
     "server address" (refer to 3.4.12. ) is of course missing at the
     server side.

   Reference:

     The definition of this term is based on the structured type
     "SecurityParameters" as defined in clause 6.1 of [RFC5246].

   Term relations:

     -



3.4.14. Term "Resumable (D)TLS client session endpoint state"

   Definition:


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     Synonym for a semi-permanent (D)TLS client session endpoint state
     (3.4.8. ).

   Reference:

     The term "is resumable" is part of the glossary of [RFC5246].

   Term relations:

     -

3.4.15. Term "Resumable (D)TLS server session endpoint state"

   Definition:

     Synonym for a semi-permanent (D)TLS server session endpoint state
     (3.4.9. ).

   Reference:

     The term "is resumable" is part of the glossary of [RFC5246].

   Term relations:

     -

3.4.16. Term "Resumable (D)TLS session"

   Definition:

     Synonym for a semi-permanent (D)TLS session (3.2.2. ).

   Notes:

     Expanded term: A (D)TLS session where the (D)TLS server session
     state as well as the (D)TLS client session state are both
     resumable.  A (D)TLS session state is called resumable, if its
     (D)TLS session identifier value is non-empty.

   Reference:

     The term "is resumable" is part of the glossary of [RFC5246].

   Term relations:

     -



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3.4.17. Term "Resumed (D)TLS session"

   Definition:

     A resumable (D)TLS session after the successful execution of a
     (D)TLS abbreviated handshake procedure.

   Notes:

     1: The (D)TLS session identifier value (of the resumed (D)TLS
     session) is identical to the previous value of the resumable
     (D)TLS session.

     2: The (D)TLS connection, which is established with the (D)TLS
     abbreviated handshake based on the existing resumable (D)TLS
     session, may be created while the original (D)TLS connection,
     which was established via the (D)TLS full handshake from which the
     resumable (D)TLS client and server session endpoint states and
     hence the resumable (D)TLS session were derived, is still
     established, or only after this original (D)TLS connection is
     already terminated.

     3: Several new (D)TLS connections may be established using (D)TLS
     abbreviated handshakes based on the same resumable (D)TLS session.
     If the first (D)TLS connection is established using an (D)TLS
     abbreviated handshake based on a resumable (D)TLS session, then we
     may say that this (D)TLS session becomes a resumed (D)TLS session
     at this first (D)TLS abbreviated handshake's end time.

   Reference:

     The term is introduced in the glossary of [RFC5246], refer to
     "session_id".

   Term relations:

     Definition based on terms "resumable (D)TLS session" (3.4.16. ),
     and "(D)TLS abbreviated handshake" (3.4.6. ).Term "(D)TLS session
     renegotiation"

   Definition:

     A (D)TLS session level concept which leads, - by the execution of
     a (D)TLS handshake procedure (full or abbreviated) -, to the
     update of the (D)TLS protocol status "connection-level"
     information of an DATA TRANSFER READY (D)TLS connection, for the
     purpose of the establishment of new cryptographic parameters.


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   Notes:

     1: The initial (D)TLS full handshake or (D)TLS abbreviated
     handshake is not regarded as a (D)TLS session renegotiation as
     this handshake is executed on a (D)TLS connection which is in the
     state IDLE.  After this initial handshake is finished the (D)TLS
     connection state is changed to DATA TRANSFER READY, and thus all
     following (D)TLS full handshakes or (D)TLS abbreviated handshakes
     on that (D)TLS connection are regarded as (D)TLS session
     renegotiation.  The (D)TLS handshake related to a (D)TLS session
     renegotiation is always cryptographically protected by the current
     (D)TLS connection state.2: The (D)TLS connection state remains in
     DATA TRANSFER READY during and after the (D)TLS session
     renegotiation.

   Reference:

     [RFC5246]

   Term relations:

     Definition based on terms "(D)TLS full handshake" (3.4.5. ),
     "(D)TLS abbreviated handshake" (3.4.6. ), and "Data transfer ready
     (D)TLS connection" (3.4.7. ).

3.4.18. Term "(D)TLS session resumption"

   Definition:

     A (D)TLS session level concept which represents the execution of a
     (D)TLS abbreviated handshake procedure on an existing (D)TLS
     session, i.e., a semi-permanent (D)TLS session, for the purpose of
     either deriving a further DATA TRANSFER READY (D)TLS connection or
     updating of an existing DATA TRANSFER READY (D)TLS connection.

   Reference:

     [RFC5246], [RFC5764], [RFC5077]

   Term relations:

     Refer to "Data transfer ready (D)TLS connection" (3.4.7. 3.4.12.
     ), "(D)TLS abbreviated handshake" (3.4.6. ), and "Semi-permanent
     (D)TLS session" (3.2.2. 3.4.8. )





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3.4.19. Term "(D)TLS session identifier"

   Definition:

     A (D)TLS protocol parameter representing the identification
     allocated to a particular semi-permanent (D)TLS session.

   Notes:

     1: The definition is consistent and not redefining the explanatory
     description of a "session identifier" in the TLS glossary, as
     contained in Appendix B/[RFC5246].

     2: This definition may need to be extended by additional
     consideration of the session ticket based TLS session resumption
     mechanism as defined in [RFC5077].  There would be then two TLS
     protocol parameters (session_id and SessionTicket) as possible
     identifiers (both protocol parameters are mutually exclusive).

   Reference:

     [RFC5077]

   Term relations:

     Definition based on the term "semi-permanent (D)TLS session"
     (3.2.2. ).

3.5. Colloquially used terms

   This clause provides a list of terms which are not introduced,
   described or defined by (D)TLS RFCs, but sometimes used in
   discussions or other documents.

3.5.1. Term "(D)TLS session re-establishment"

   Definition:

     -

   Notes:

     There does not exist any definition so far.

   Reference:

     None.


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   Term relations:

     Still open, dependent on definition.

3.5.2. Term "(D)TLS session rekeying"

   Definition:

     -

   Notes:

     There doesn't exist any definition so far (to be confirmed).
     [RFC5763], clause 6.8 provides a high-level description of a
     "rekeying concept" in context of DTLS-based SRTP key management.

   Reference:

     None.

   Term relations:

     Still open, dependent on definition.

3.5.3. Term "(D)TLS rehandshake"

   Definition:

     -

   Notes:

     There does not exit any definition so far.

   Reference:

     The term is used in [RFC5764].

   Term relation:

     The term can be interpreted as a synonym for "(D)TLS
     renegotiation".







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4. Security Considerations

   FIXTHIS

5. IANA Considerations

   FIXTHIS



6. References

6.1. Normative References

   [RFC2119] RFC 2119 (03/1997), "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14.

   [RFC4949] RFC 4949 (08/2007), "Internet Security Glossary,
             Version 2"

   [RFC5077] RFC 5077 (01/2008), "Transport Layer Security (TLS)
             Session Resumption without Server-Side State"

   [RFC5246] RFC 5246 (08/2008), "The Transport Layer Security (TLS)
             Protocol, Version 1.2"

   [RFC5746] RFC 5746 (02/2010), "Transport Layer Security (TLS)
             Renegotiation Indication Extension"

   [RFC5763] RFC 5763 (05/2010), "Framework for Establishing a Secure
             Real-time Transport Protocol (SRTP) Security Context Using
             Datagram Transport Layer Security (DTLS)"

   [RFC5764] RFC 5764 (05/2010), "Datagram Transport Layer Security
             (DTLS) Extension to Establish Keys for the Secure Real-
             time Transport Protocol (SRTP)"

   [RFC6347] RFC 6347 (02/2012), "Datagram Transport Layer Security
             Version 1.2"

6.2. Informative References

   [ITU-T X.200]  Recommendation ITU-T X.200 (07/1994), "Information
             technology - Open Systems Interconnection - Basic
             Reference Model: The basic model."




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   [ITU-T X.213]  Recommendation ITU-T X.213 (10/2001), "Information
             technology - Open Systems Interconnection - Network
             service definition."

   [ITU-T X.214]  Recommendation ITU-T X.214 (11/1995), "Information
             technology - Open Systems Interconnection - Transport
             service definition."

7. CHANGE LOG

7.1. Initial draft name "draft-guballa-tls-terminology"

7.1.1. Version "-00"

   Following definition template is used:

     Term "<term>"

          Definition:
            <definition>.

          Notes:
            <comments, complementary information>

          Reference:
            <references>

          Term relations:
            <references to terms reused by this definition>



7.1.2. Changes against "-00"

   o  Editorial changes according to RFC Style Guide

   o  Hierarchical framework added (appendix A)

   o  List of authors extended

   o  Clarification added: handshakes for session renegotiation are
      always cryptographically protected

   o  Reference to RFC5763 added for "(D)TLS session rekeying"

   o  Clarification of relation with Internet Security Glossary
      [RFC4949]


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   o  Missing references fixed

   o  List of colloquially used terms extended

7.1.3. Changes against "-01"

   o  No changes

7.1.4. Changes against "-02"

   o  Author's Addresses updated

7.1.5. Changes against "-03"

   o  Editor's address updated

7.1.6. Changes against "-04"

   o  Author's address updated






























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Appendix A.                  Hierarchical Framework

   This section provides an overview on the hierarchy of the terms
   defined in this draft.  The dependency is indicated by arrows as
   follows:

   "foo"--->"bar" indicates that the definition of term "foo" is based
   on the term "bar".









































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A.1. Framework for (D)TLS Connection related Definitions

   +-------+              +---------------+
   |(D)TLS |              |(D)TLS protocol|<-----------------------+
   |message|<-----+    +->|implementation |<---+                   |
   +-------+      |    |  +---------------+    |                   |
    ^  ^  ^       |    |     ^                 |                   |
    |  |  |       +<---|-----|--+<-----+<---+  |                   |
    |  |  |       ^    |     |  ^      ^    |  |                   |
    |  |  |  +----|----|+    |  |      |    |  |                   |
    |  |  |  |(D)TLS    |    |  |      |   +|--|-------------+     |
    |  |  |  |connection|    |  |      |   |(D)TLS connection|     |
    |  |  |  |endpoint  |    |  |      |   |endpoint         |     |
    |  |  |  |identifier|    |  |      |   +-----------------+     |
    |  |  |  +----------+    |  |      |    ^    ^    ^            |
    |  |  |                  |  |      |    |    |    |            |
    |  |  +----------+       |  |      +----|----|--+ |            |
    |  |             |       |  |           |    |  | |            |
    | +|-------+     |       | +|-----------|+   | +|-|----------+ |
    | |(D)TLS  |     |       | |(D)TLS client|   | |(D)TLS server| |
    | |message |     |       | |connection   |   | |connection   | |
    | |sequence|<-+  |       | |endpoint     |   | |endpoint     | |
    | +--------+  |  |       | +-------------+   | +-------------+ |
    |        ^    |  |       |  ^      ^         |    ^         ^  |
    |        |    |  |       |  |      |         |    |         |  |
   +|--------|-+ +|--|-----+ |  +<-----|---------|----|-----+   |  |
   |(D)TLS     | |(D)TLS   | |  ^      |         |    |     |   |  |
   |abbreviated| |full     | |  |  +---|---------|----|-----|-->+  |
   |handshake  | |handshake| |  |  |   |         |    |     |   ^  |
   +-----------+ +---------+ |  |  |   |    +--->+    |     |   |  |
    ^             ^          |  |  |   |    |    ^    |     |   |  |
    |             |          |  |  |   |    |    |    |     |   |  |
   +|-------------|+     +---|--|--|+ +|----|+  +|----|+   +|---|--|+
   |Data transfer  |---->|(D)TLS    | |(D)TLS|  |(D)TLS|   |(D)TLS  |
   |ready (D)TLS   |     |connection| |client|  |server|   |endpoint|
   |connection     |     +----------+ |role  |  |role  |   +--------+
   +---------------+                  +------+  +------+

              Figure 1: Terms related to "(D)TLS connection"










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A.2. Framework for (D)TLS Session related Terms

   +---------+ +----------+ +-----------+ +-----------+ +----------+
   |(D)TLS   | |(D)TLS    | |(D)TLS srv | |(D)TLS clnt| |(D)TLS    |
   |full     | |connection| |session    | |session    | |session   |
   |handshake| +----------+ |endp. state| |endp. state| |identifier|
   +---------+  ^           +-----------+ +-----------+ +----------+
    ^           |            ^             ^                     ^
    |  +--------+            |             |                     |
    |  |                     |             |                     |
    |  |   +---------------->+<------------|-----------+         |
    |  |   |                               |           |         |
    |  |   |             +---------------->+           |         |
    |  |   |             |                 ^           |         |
    |  |   |         +---|--------->+------|------>+---|-------->+
    |  |   |         |   |          ^      |       ^   |         ^
    |  |   |         |   |          |      |       |   |         |
    |  |  +|---------|+ +|----------|+ +---|-------|+ +|---------|+
    |  |  |Semi-perm. | |Semi-perm.  | |Transient   | |Transient  |
    |  |  |(D)TLS     | |(D)TLS      | |(D)TLS      | |(D)TLS     |
    |  |  |srv session| |clnt session| |clnt session| |srv session|
    |  |  |endp. state| |endp. state | |endp. state | |endp. state|
    |  |  +-----------+ +------------+ +------------+ +-----------+
    |  |   ^             ^                      ^      ^
    |  +<--|-------------|-------------------+  |      |
    |  ^   |             |                   |  |      |
    +<-|---|-------------|----------------+  |  |      |
    ^  |   |             |                |  |  |      |
    |  |   |             |                |  |  |      |
   +|--|---|------+      |               +|--|--|------|+
   |Semi-permanent|------+               |Transient     |
   |(D)TLS session|                      |(D)TLS session|
   +--------------+                      +--------------+
                 ^                        ^
                 |       +-------+        |
                 +-------|(D)TLS |--------+
                         |session|
                         +-------+

                Figure 2: Terms related to "(D)TLS session"









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A.3. Framework for (D)TLS Session Resumption and (D)TLS Session
renegotiation

   +---------+               +-----------+
   |(D)TLS   |               |(D)TLS     |
   |full     |               |abbreviated|
   |handshake|               |handshake  |
   +---------+               +-----------+
    ^  ^  ^                   ^
    |  |  |                   |
    |  |  +-------------------|---+
    |  |                      |   |
    | +|------------------+   |  +|-------------+
    | |Data transfer ready|-->+  |Semi-permanent|
    | |(D)TLS connection  |   ^  |(D)TLS session|
    | +-------------------+   |  +--------------+
    |  ^                 ^    |   ^
    |  |  +--------------|--->+   |
    |  |  |              |    ^   |
   +|--|--|-------+     +|----|---|----+
   |(D)TLS session|     |(D)TLS session|
   |renegotiation |     |resumption    |
   +--------------+     +--------------+

    Figure 3: Terms related to "(D)TLS session resumption" and "(D)TLS
                          session renegotiation"


   Acknowledgments

   <Add any acknowledgements>


















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Authors' Addresses

   Jens Guballa (editor)
   GERMANY

   Email: jens@guballa.de


   Juergen Stoetzer-Bradler
   GERMANY

   Email: Juergen.S-B.ietf@email.de


   He Bing
   ALCATEL-LUCENT SHANGHAI BELL
   388 Ningqiao Road
   201206 Shanghai
   CHINA

   Email: Bing.He@alcatel-sbell.com.cn




























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