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  UTA Working Group                                            P. Urien
  Internet Draft                                      Telecom ParisTech
  Intended status: Experimental

                                                           June 21 2015
  Expires: December 2015

                          TLS and DTLS Security Modules
                    draft-urien-uta-tls-dtls-security-module-00.txt


Abstract

   Security and trust are very critical topics in the context of the
   anywhere, anytime, anything internet connectivity. TLS and DTLS are
   two major IETF protocols widely used to secure IP exchanges.
   According to COAP, DTLS is the protocol used by constraint nodes in
   the Internet of Things (IoT) context.

   In this draft we specify an ISO7816 interface for TLS and DTLS
   secure modules based on ISO7816 secure chips, which are today
   manufactured per billions every year.

   Secure elements are cheap secure microcontrollers whose size is
   about 25mm2 and whose security is ranked by evaluations typically
   according to Common Criteria (CC) standards.

   The support of TLS and DTLS is based on the EAP-TLS protocol, and
   the IETF draft "EAP Support in smartcard" describing EAP-TLS support
   for secure elements. First implementation demonstrates that such low
   cost security modules are realistic, with a setup time for handshake
   completion under the second.


Requirements Language

   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.














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Status of this Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF). Note that other groups may also distribute
   working documents as Internet-Drafts. The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six
   months and may be updated, replaced, or obsoleted by other documents
   at any time. It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 2015.


Copyright Notice

   Copyright (c) 2015 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. Code Components extracted from this
   document must include Simplified BSD License text as described in
   Section 4.e of the Trust Legal Provisions and are provided without
   warranty as described in the Simplified BSD License.



















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Table of Contents

   Abstract........................................................... 1
   Requirements Language.............................................. 1
   Status of this Memo................................................ 2
   Copyright Notice................................................... 2
   1 Overview......................................................... 4
   2 The EAP-TLS Smartcard............................................ 4
      2.1 The EAP-TLS protocol........................................ 4
      2.2 The EAP-TLS Smartcard....................................... 6
   4 The TLS Security Module.......................................... 6
      4.1 EAP-TLS for TLS Security Module............................. 6
      4.2 The TLS / EAP-TLS Software Bridge........................... 8
      4.3 The TLS Security Module Encryption and Decryption procedures 8
   5 The DTLS Security Module........................................ 10
      5.1 EAP-TLS for DTLS Security Module........................... 10
      5.2 The DTLS / EAP-TLS Software Bridge......................... 11
      5.3 The DTLS Security Module Encryption and Decryption procedures
      ............................................................... 12
   6 Example of TLS processing by the TLS security module............ 14
   7 Example of DTLS processing by the DTLS security module.......... 16
   8 Security Considerations......................................... 22
   9 IANA Considerations............................................. 22
   10 References..................................................... 22
      10.1 Normative References...................................... 22
      10.2 Informative References.................................... 23
   11 Authors' Addresses............................................. 23

























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1 Overview

   Security and trust are very critical topics in the context of the
   anywhere, anytime, anything internet connectivity. TLS [TLS 1.0]
   [TLS 1.1], [TLS 1.2] and DTLS [DTLS 1.0] [DTLS 1.2] are two major
   IETF protocols widely used to secure IP exchanges. According to
   [COAP], DTLS is the protocol used by constraint nodes in the
   Internet of Things (IoT) context. In this draft we specify an
   interface for TLS and DTLS secure modules based on [ISO7816] secure
   chips, which are today manufactured per billions every year. Secure
   elements are cheap secure microcontrollers whose size is about 25mm2
   and whose security is ranked by evaluations typically according to
   Common Criteria (CC) standards. The support of TLS and DTLS is based
   on the EAP-TLS [EAP-TLS] protocol, and the IETF draft [EAP SC] "EAP
   Support for Smartcards" describing EAP-TLS support for secure
   elements. First implementation demonstrate that such low cost
   security modules are realistic, with a setup time for handshake
   completion, under the second.


2 The EAP-TLS Smartcard

2.1 The EAP-TLS protocol

   The EAP-TLS [EAP-TLS] protocol (as illustrated by figure 1)defines a
   transparent transport of the TLS protocol until the exchange
   finished messages (both for server and client). According to EAP-
   TLS, and similarly to DTLS [DTLS 1.0] [DTLS 1.2], messages are
   grouped into a series of flights (four for the TLS full mode, and
   three for the TLS Session Resumption.

   The EAP-TLS protocol supports segmentation and reassembly operations
   managed via the "Flags" byte, which is detailed below:


     0 1 2 3 4 5 6 7
    +-+-+-+-+-+-+-+-+
    |L M S R R R R R|
    +-+-+-+-+-+-+-+-+

     L = Length included
     M = More fragments
     S = Start bit
     R = Reserved

   - The L bit (length included) is set to indicate the presence of the
   four-octet TLS Message Length field, and MUST be set for the first
   fragment of a fragmented TLS message or set of messages.
   - The M bit (more fragments) is set on all but the last fragment.
   - The S bit (EAP-TLS start) is set in an EAP-TLS Start message.


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   When an EAP-TLS peer receives an EAP-Request packet with the M bit
   set, it MUST respond with an EAP-Response with EAP-Type=EAP-TLS and
   no data. This serves as a fragment ACK.


      Authenticating Peer     Authenticator
      EAP-TLS Smartcard (SC)     SC User
      -------------------     -------------
                              <- EAP-Request/
                              Identity
      EAP-Response/
      Identity (MyID) ->
                              <- EAP-Request/
                              EAP-Type=EAP-TLS
                              Flags
                              (TLS Start)
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags
      (TLS client-hello)->                               Flight 1
                              <- EAP-Request/
                              EAP-Type=EAP-TLS
                              Flags
                              (TLS server-hello,         Flight 2
                                TLS certificate,
                       [TLS server-key-exchange,]
                        TLS certificate-request,
                           TLS server-hello-done)
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags
      (TLS certificate,                                  Flight 3
       TLS client-key-exchange,
       TLS certificate-verify,
       TLS change-cipher-spec,
       TLS finished) ->
                              <- EAP-Request/
                              EAP-Type=EAP-TLS
                              Flags
                              (TLS change-cipher-spec,   Flight 4
                               TLS finished)
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags         ->

                              <- EAP-Success

   Figure 1. The EAP-TLS protocol




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2.2 The EAP-TLS Smartcard

   The "EAP Support in Smartcard" draft [EAP SC] specifies an ISO7816
   interface for a secure element (named EAP-TLS smartcard, in figure
   1) that fully processes the EAP-TLS protocol until the reception of
   the EAP-Success message.

   The two main commands are detailed in figure 2:
   - Reset-State, which resets the EAP-TLS state machine ,
   - Process-EAP that transports TLS flights encapsulated in EAP-TLS
   messages.

       +------------------------+-----+-----+----+----+----+----+
       |         Command        |Class| INS | P1 | P2 | Lc | Le |
       +------------------------+-----+-----+----+----+----+----+
       |       Process-EAP      | A0  |80-88| 00 | 00 | xx | yy |
       +------------------------+-----+-----+----+----+----+----+
       |       Reset-State      | A0  |  19 | 10 | 00 | 00 | 01 |
       +------------------------+-----+-----+----+----+----+----+
                                Figure 2

4 The TLS Security Module


4.1 EAP-TLS for the TLS Security Module

   TLS security modules are based on EAP-TLS devices, performing, as
   illustrated by figure 3, a transparent encapsulation of TLS packets.

   The EAP-Request-Identity message and EAP-Success message are not
   used by the TLS secure modules.





















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      Security Module (SM)       SM User
      -------------------     -------------

                              <- EAP-Request/
                              EAP-Type=EAP-TLS
                              Flags
                              (TLS Start)
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags
      (TLS client-hello)->
                              <- EAP-Request/
                              EAP-Type=EAP-TLS
                              Flags
                              (TLS server-hello,
                                TLS certificate,
                       [TLS server-key-exchange,]
                        TLS certificate-request,
                           TLS server-hello-done)
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags
      (TLS certificate,
       TLS client-key-exchange,
       TLS certificate-verify,
       TLS change-cipher-spec,
       TLS finished) ->
                              <- EAP-Request/
                              EAP-Type=EAP-TLS
                              Flags
                              (TLS change-cipher-spec,
                               TLS finished)
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags         ->

   =======================================================
                Four ways TLS Handshake Completion
   =======================================================

   Figure 2. The TLS Handshake Completion with the Security Module










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4.2 The TLS / EAP-TLS Software Bridge


   A software bridge, illustrated by figure 3 extracts TLS flights from
   TLS packets, and manages EAP-TLS messages exchanged with the
   Security Module.

               +----------+            +-----------+
        TLS    |    TLS   |   EAP-TLS  |    TLS    |
       packet  |  EAP-TLS |   Packet   |  Security |
     <=======> |   Bridge | <========> |   Module  |
               +----------+            +-----------+

   Figure 3. The TLS / EAP-TLS Software Bridge

4.3 The TLS Security Module Encryption and Decryption procedures

   After the completion of the TLS four ways or three ways handshake
   (notified by the delivery of EAP-Success message in EAP-TLS) the
   Security Module supports two procedures, Process-EAP-Encrypt and
   Process-EAP-Decrypt, in order to respectively compute TLS encrypted
   packets (see figure 4) or to check and decrypt the payload of TLS
   ciphered packets (see figure 5).

                              Process-EAP-Encrypt(Type)
                              <- EAP-Request/
                              EAP-Type=EAP-TLS
                              Flags
                             (Payload= Clear Text)
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags
      (Payload= TLS Encrypted
       Record Layer Message)->

   Figure 4. Generation of TLS encrypted packet by TLS Security module

                              Process-EAP-Decrypt
                              <- EAP-Request/
                              EAP-Type=EAP-TLS
                              Flags
                              (Payload= TLS Encrypted
                               Record Layer Message)->
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags
      (Payload= TLS Clear
       Record Layer payload)->

   Figure 5. Generation of TLS decrypted packets


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   In the case of the Process-EAP-Encrypt(Type) procedure the payload
   of the EAP-TLS packet (see figure 4) is the clear text to be
   encrypted in the TLS Record Layer packet. The SM adds the Type field
   indicated in the Process-EAP-Encrypt command, and performs all
   needed operations in order to compute the TLS encrypted packet
   (including HMAC and optional padding bytes see figure 6),
   encapsulated in the EAP-Response message (depicted in figure 4).

   In the case of the Process-EAP-Decrypt() procedure, the payload of
   the EAP-TLS packet (see figure 5) is the received TLS Record Layer
   encrypted packet, as showed by figure 6. The Security Module checks
   the HMAC, and upon success deciphers the encrypted payload; the
   resulting data is returned encapsulated in the EAP-Response message.

       +------+---------+--------+----------------------------+
       | Type | Version | Length |         Encrypted          |
       +------+---------+--------+          Payload           |
       +                                                      |
       +           +------+-----+------------+----------------+
       +           | HMAC | Pad | Pad Length |
       +-----------+------+-----+------------+

   Figure 6. A TLS (Record Layer) encrypted packet.

   The figure 7 details the structure of the Security Module command
   needed for the encryption and decryption of TLS packets.

   +-------------+-----+-----+----+------------+----+----+---------+
   |   Command   |Class| INS | P1 |     P2     | Lc | Le |    SW   |
   +-------------+-----+-----+----+------------+----+----+---------+
   | Process-EAP | A0  |80-88| 00 | 80 || Type | xx | yy | 9000 OK |
   |   Encrypt   |     |     |    |            |    |    | 6985 ERR|
   +-------------+-----+-----+----+------------+----+----+---------+
   | Process-EAP | A0  |80-88| 00 |     00     | xx | yy | 9000 OK |
   |   Decrypt   |     |     |    |            |    |    | 6985 ERR|
   +-------------+-----+-----+----+------------+----+----+---------+

   Figure 7. The Security Module ISO7816 commands














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5 The DTLS Security Module

5.1 EAP-TLS for the DTLS Security Module

      Security Module (SM)       SM User
      -------------------     -------------
                              <- EAP-Request/
                              EAP-Type=EAP-TLS
                              Flags
                              (TLS Start)
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags
      (DTLS client-hello) ->                              Flight 1
                              <- EAP-Request/
                              DTLS Hello-Verify-Request   Flight 2
                              (contains cookie)
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags
      (DTLS client-hello
       with cookie)      ->                               Flight 3
                              <- EAP-Request/
                              EAP-Type=EAP-TLS
                              Flags
                              (DTLS server-hello,
                                DTLS certificate,         Flight 4
                       [DTLS server-key-exchange,]
                        DTLS certificate-request,
                           DTLS server-hello-done)
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags
      (DTLS certificate,
       DTLS client-key-exchange,
       DTLS certificate-verify,                           Flight 5
       DTLS change-cipher-spec,
       DTLS finished) ->
                              <- EAP-Request/
                              Flags
                              EAP-Type=EAP-TLS
                              (DTLS change-cipher-spec,   Flight 6
                               DTLS finished)
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags         ->
   =======================================================
               Four ways DTLS Handshake Completion
   =======================================================

   Figure 8. The DTLS handshake completion with the Security Module

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   In a way similar to TLS (see figure 8), DTLS messages are
   encapsulated in EAP-TLS messages.

5.2 The DTLS / EAP-TLS Software Bridge

   A software bridge, illustrated by figure 9 extracts DTLS flights
   from DTLS packets, and manages EAP-TLS exchanges with the Security
   Module.


               +----------+            +-----------+
      DTLS     |   DTLS   |   EAP-TLS  |    DTLS   |
      packets  |  EAP-TLS |   Packets  |  Security |
     <=======> |  Bridge  | <========> |   Module  |
               +----------+            +-----------+

   Figure 9. DTLS / EAP-TLS software bridge

   The DTLS security module doesn't manage handshake messages
   fragmentation and reassembly. These operations are handled by the
   software bridge during the DTLS three ways or four ways handshake.
   Timeout and retransmission are also managed by the bridge entity.

   According to [DTLS 1.0] finished messages have no sensitivity to
   fragmentation. There are computed as if each handshake message had
   been sent as a single fragment. The security module (see figure 10)
   deals with handshake message with the fields fragment-offset set to
   zero, and fragment-length equal to length. Because the handshake
   sequence in not used in cryptographic calculations, it is fully
   managed by the bridge. The security module does not take into
   account the received messages sequences, and produces handshake
   messages starting from zero (at the DTLS first hello message
   generation) and incremented for every message.

   HandshakeType msgtype;
   uint24 length;
   uint16 message-sequence;
   uint24 fragment-offset;
   uint24 fragment-length;
   [Handshake Message]

   Figure 10. Structure of the DTLS Handshake message.

   It also should be noted that according to the DTLS protocol [DTLS
   1.0] in cases where the cookie exchange is used, the initial
   ClientHello and HelloVerifyRequest are NOT included in the Finished
   MAC.

   When the Security Module builds the client finished message it sets
   the EPOCH field to one and resets the sequence number used by the

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   record layer. The record layer packet structure is detailed by
   figure 11.

   struct {
   ContentType type;
   ProtocolVersion version;
   uint16 epoch;
   uint48 sequence-number;
   uint16 length;
   opaque fragment[DTLSPlaintext.length];
   } DTLSPlaintext;

   Figure 11. DTLS Record Layer packet structure


   According to [DTLS 1.0] the DTLS MAC is the same as that of TLS 1.1.
   However, rather than using TLS's implicit sequence number, the
   sequence number used to compute the MAC is the 64-bit value formed
   by concatenating the epoch and the sequence number in the order they
   appear on the wire. TLS MAC calculation is parameterized on the
   protocol version number, which, in the case of DTLS, is the on-the-
   wire version, i.e., {254,255 } for DTLS 1.0.

5.3 The DTLS Security Module Encryption and Decryption procedures

   Upon the completion of the DTLS handshake, i.e. after the generation
   of finished messages (both and on client and server side) the record
   layer is fully handle by the security module, which checks and
   decrypts all incoming packets (see figure 13), and produces
   encrypted and HMACed packets (see figure 12).

                              Process-EAP-Encrypt(Type)
                              <- EAP-Request/
                              EAP-Type=EAP-TLS
                              Flags
                             (Payload= Clear Text)
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags
      (Payload= DTLS Encrypted
       Record Layer Message)->

   Figure 12. Generation of DTLS encrypted packet by the DTLS Security
   module








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                              Process-EAP-Decrypt
                              <- EAP-Request/
                              EAP-Type=EAP-TLS
                              Flags
                              (Payload= DTLS Encrypted
                               Record Layer Message)->
      EAP-Response/
      EAP-Type=EAP-TLS
      Flags
      (Payload= DTLS Clear
       Record Layer payload)->

   Figure 13. Generation of TLS decrypted packets






































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6 Example of TLS processing by the TLS security module

   The following choreography illustrates the processing of a TLS (1.0)
   resume session by the TLS security module. The CipherSuite is AES-
   SHA1.

   // RESET the Security Module
   >> A0 19 10 00 00
   << 90 00

   // Send EAP-TLS-Start in EAP-Request
   // last four bytes represent the time
   >> A0 80 00 00 0A 01 14 00 06 0D 20 55 82 E9 D1

   // Flight 1
   // Client Hello in EAP-Response
   << 02 14 00 5C 0D 80 00 00 00 52 16 03 01 00 4D 01 00 00 49 03
      01 55 82 E9 D1 BE 21 DF 71 68 C3 14 BB DC 09 57 24 DA 77 F1
      EA C1 9F 54 AF 0F E4 61 C9 5A 3F 06 93 20 34 1A 3F 0A E5 6C
      C0 39 F1 E2 9A F7 D3 D6 6E C0 91 CC EB 77 61 7D 88 FF C7 00
      F9 C3 6D 1F 1F 8C 00 02 00 2F 01 00
      90 00

   // Flight 2
   // Server Hello + CCS + Finished in EAP-Request
   // 1st fragment

   >> A0 80 00 00 8A 01 0D 00 8A 0D C0 00 00 00 8A 16 03 01 00 4A
      02 00 00 46 03 01 55 82 EA 66 4D ED 28 C0 E2 4F 22 12 01 35
      49 82 61 5A FC 29 64 3B 20 1D 3A D4 00 39 91 27 07 06 20 34
      1A 3F 0A E5 6C C0 39 F1 E2 9A F7 D3 D6 6E C0 91 CC EB 77 61
      7D 88 FF C7 00 F9 C3 6D 1F 1F 8C 00 2F 00 14 03 01 00 01 01
      16 03 01 00 30 85 D5 76 49 D3 58 C9 93 D8 03 B1 91 19 78 3F
      16 A1 3A DF 03 54 53 63 B6 42 A5 5A 8A 23 C2 C5 AD 84 75 30
      85 BE 75

   // EAP-TLS ACK
   << 02 0D 00 06 0D 00
      90 00

   // 2nd fragment
   >> A0 80 00 00 10 01 0E 00 10 0D 00 26 92 99 2A 9E 7F FF 2E
      BC CB

   // Flight 3
   // Client CCS + Finished in EAP-Response
   << 02 0E 00 45 0D 80 00 00 00 3B 14 03 01 00 01 01 16 03 01 00
      30 86 8A 10 A2 85 5F DA D8 52 16 D6 57 12 75 A6 57 A2 20 1B
      A5 5B F0 0A E5 34 62 FF 92 28 BC DD 72 5E D7 6E C0 D4 A5 52
      1F AA F5 6D 7C 8A 37 02 54
      90 00

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   // TLS handshake completion

   // Process-EAP-Decrypt
   >> A0 80 00 00 2B 01 0F 00 2B 0D 00 17 03 01 00 20 75 1A 28 2D
      F3 E1 12 D5 19 7C 3E 38 CB 49 D6 43 CF B0 F3 E5 A3 1A BF A1
      E0 75 AE A8 07 89 B0 45

   // Empty Record Layer Payload
   << 02 0F 00 0A 0D 80 00 00 00 00
      90 00

   //Process-EAP-Decrypt

   >> A0 80 00 00 2B 01 10 00 2B 0D 00 17 03 01 00 20 A0 65 57 15
      17 D2 DA 92 FF A3 7F 07 F4 95 53 86 4C 55 F3 2C 87 6B A8 CB
      2F 36 F3 71 D2 AD A3 F7

   // Record Layer Clear Payload = 31 32 33 34 0D OA
   << 02 10 00 10 0D 80 00 00 00 06 31 32 33 34 0D 0A
      90 00

   // Process-EAP-Encrypt type=17h, payload = 31 32 33 34 0D 0A
   >> A0 80 00 97 0C 01 11 00 0C 0D 00 31 32 33 34 0D 0A

   // Encrypted TLS Record Layer packet in EAP-Response
   << 02 11 00 2F 0D 80 00 00 00 25 17 03 01 00 20 15 06 B7 7D 1F
      1E F3 51 4A 8E 70 3C AE B2 EF EF D0 45 A7 1E 3F 68 92 AF 0C
      09 C7 91 97 F7 C2 E6
      90 00






















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7 Example of DTLS processing by the DTLS security module

   The following choreography illustrates the processing of a DTLS full
   session the DTLS security module. The CipherSuite is AES-SHA1.


   // RESET the Security Module
   >> A0 19 10 00 00
   << 90 00

   // Send EAP-TLS-Start in EAP-Request
   // The last four bytes represent the time

   >> A0 80 00 00 0A 01 14 00 06 0D 20 55 83 BF CA

   // Flight 1
   // DTLS ClientHello (no cookie) in EAP-Response
   // RL-seq=0, RL-epoch=0, Handshake-seq=0
   << 02 14 00 4D 0D 80 00 00 00 43 16 FE FF 00 00 00 00 00 00 00
      00 00 36 01 00 00 2A 00 00 00 00 00 00 00 2A FE FF 55 83 BF
      CA DD 4C 24 32 85 D1 A5 21 EB EE F3 33 50 88 17 6B 48 6A CB
      24 E6 28 8B FE 3C 85 F3 F1 00 00 00 02 00 2F 01 00
      90 00

   DTLS Bridge sends 67 bytes
   DTLS Bridge receives RL-Seq=0, RL-epoch=0, Handshake-seq=0

   // Flight 2 DTLS HelloVerifyRequest (contains cookie)
   // DTLS HelloVerifyRequest in EAP-Response

   >> A0 80 00 00 36 01 01 00 36 0D 00 16 FE FF 00 00 00 00 00 00
      00 00 00 23 03 00 00 17 00 00 00 00 00 00 00 17 FE FF 14 C2
      38 AC 8C F8 F5 CE CA 9B 9E F1 2F 8A D1 9E 2F 84 27 F2 FF

   // Flight 3 DTLS HelloClient (contains cookie)
   // DTLS ClientHello in EAP-Response
   // RL-seq=1, RL-epoch=0, Handshake-seq=1

   << 02 01 00 61 0D 80 00 00 00 57 16 FE FF 00 00 00 00 00 00 00
      01 00 4A 01 00 00 3E 00 01 00 00 00 00 00 3E FE FF 55 83 BF
      CA DD 4C 24 32 85 D1 A5 21 EB EE F3 33 50 88 17 6B 48 6A CB
      24 E6 28 8B FE 3C 85 F3 F1 00 14 C2 38 AC 8C F8 F5 CE CA 9B
      9E F1 2F 8A D1 9E 2F 84 27 F2 FF 00 02 00 2F 01 00
      90 00

   DTLS Bridges sends 87 bytes
   DTLS Bridges receives
   RL-seq=1 RL-epoch=0 Handshake-seq=1
   RL-seq=2 RL-epoch=0 Handshake-seq=2
   RL-seq=3 RL-epoch=0 Handshake-seq=3

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   RL-seq=4 RL-epoch=0 Handshake-seq=4

   // Flight 4
   // DTLS ServerHello, Certificate, CertificateRequest
   // ServerHelloDone in EAP-Request
   // 4 record layer messages

   // EAP-TLS message 1st fragment
   >> A0 80 00 00 8A 01 02 00 8A 0D C0 00 00 02 D2 16 FE FF 00 00
      00 00 00 00 00 01 00 32 02 00 00 26 00 01 00 00 00 00 00 26
      FE FF 55 83 BF CF F6 1B 78 8E 10 05 FC F7 4C 0C 0D 9D 98 4E
      90 DA 71 EC BC 83 45 97 4A 71 D9 89 19 C1 00 00 2F 00 16 FE
      FF 00 00 00 00 00 00 00 02 02 4E 0B 00 02 42 00 02 00 00 00
      00 02 42 00 02 3F 00 02 3C 30 82 02 38 30 82 01 A1 A0 03 02
      01 02 02 02 00 8B 30 0D 06 09 2A 86 48 86 F7 0D 01 01 05 05
      00 30 57

   // EAP-TLS Ack
   << 02 02 00 06 0D 00
      90 00

   // 2nd fragment
   >> A0 80 00 00 8A 01 03 00 8A 0D 40 31 0B 30 09 06 03 55 04 06
      13 02 55 53 31 11 30 0F 06 03 55 04 08 13 08 56 69 72 67 69
      6E 69 61 31 10 30 0E 06 03 55 04 07 13 07 46 61 69 72 66 61
      78 31 11 30 0F 06 03 55 04 0A 13 08 5A 6F 72 6B 2E 6F 72 67
      31 10 30 0E 06 03 55 04 03 13 07 52 6F 6F 74 20 43 41 30 1E
      17 0D 31 34 30 37 31 33 32 32 34 39 30 37 5A 17 0D 32 32 30
      39 32 39 32 32 34 39 30 37 5A 30 5D 31 0B 30 09 06 03 55 04
      06 13 02

   // EAP-TLS Ack
   << 02 03 00 06 0D 00
      90 00

   // 3rd fragment
   >> A0 80 00 00 8A 01 04 00 8A 0D 40 46 52 31 14 30 12 06 03 55
      04 08 13 0B 49 6C 65 44 65 46 72 61 6E 63 65 31 0E 30 0C 06
      03 55 04 07 13 05 50 61 72 69 73 31 17 30 15 06 03 55 04 0A
      13 0E 65 74 68 65 72 74 72 75 73 74 2E 63 6F 6D 31 0F 30 0D
      06 03 55 04 03 13 06 63 6C 69 65 6E 74 30 81 9F 30 0D 06 09
      2A 86 48 86 F7 0D 01 01 01 05 00 03 81 8D 00 30 81 89 02 81
      81 00 E3 83 38 A1 60 FE 8B 24 6F 39 E6 A8 A9 81 8F BE 9C E2
      E3 7F 45

   // EAP-TLS ack
   << 02 04 00 06 0D 00
      90 00

   // 4th fragment
   >> A0 80 00 00 8A 01 05 00 8A 0D 40 2F 9B C7 41 09 B2 10 52 38

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      3F 74 46 89 C4 A1 4E 28 9D F7 22 8B AF 90 D1 3C 3C 03 4A 2F
      FC AA 03 26 3E 21 6C 19 DB 87 D7 F6 19 D6 F4 57 A4 BA 08 14
      CB B3 1C 1F 01 76 6B 08 5A 4B 40 09 8B AB C8 6E 31 25 17 78
      04 78 84 0F CB 0E B1 B9 D0 27 73 30 0D AE C1 7D BB 8E 1B 65
      0A 17 51 23 9F C9 89 62 44 38 5C E6 63 A0 72 E2 99 67 02 03
      01 00 01 A3 0D 30 0B 30 09 06 03 55 1D 13 04 02 30 00 30 0D
      06 09 2A

   // EAP-TLS Ack
   << 02 05 00 06 0D 00
      90 00


   // 5th fragment

   >> A0 80 00 00 8A 01 06 00 8A 0D 40 86 48 86 F7 0D 01 01 05 05
      00 03 81 81 00 7C 95 33 F9 17 27 BE CB 2A 85 6C A9 9E B8 4B
      07 9B 09 69 ED D1 8A 38 A5 CA 1B C6 44 06 F9 A3 BD E4 66 58
      C4 BE 92 32 C9 9E 43 42 26 9E EF 67 1D 6E A3 2C CE 59 DE 3E
      0F 07 3A 10 66 72 5E A1 E5 06 76 76 CC 8D C0 47 54 42 AB FA
      36 1C F1 8B 57 C0 A7 2B 65 52 4F 2E 36 75 D5 15 34 18 38 61
      3A 18 18 5D D5 E3 9E 8D 1C DD 3D D3 A6 93 3D 19 0C 9C FA 98
      C0 B0 5B

   // EAP-TLS Ack
   << 02 06 00 06 0D 00
      90 00

   // 6th and last fragment

   >> A0 80 00 00 48 01 07 00 48 0D 00 4F 35 CF B2 88 51 6D 9F 75
      FD 16 FE FF 00 00 00 00 00 00 00 03 00 12 0D 00 00 06 00 03
      00 00 00 00 00 06 03 01 02 40 00 00 16 FE FF 00 00 00 00 00
      00 00 04 00 0C 0E 00 00 00 00 04 00 00 00 00 00 00

   // Flight 5
   // Certificate, KeyExchange, CertificateVerify, ChangeCipherSpec
   // Finished, in EAP-Response, 2 record layer messages
   // RL-seq=2, RL-epoch=0, Handshake-seq=2,3,4,5
   // RL-seq=0, RL-epoch=0, Handshake-seq=0

   // EAP-TLS message, 1st EAP fragment
   << 02 07 00 8A 0D C0 00 00 04 0F 16 FE FF 00 00 00 00 00 00 00
      02 03 A7 0B 00 02 7F 00 02 00 00 00 00 02 7F 00 02 7C 00 02
      79 30 82 02 75 30 82 01 DE A0 03 02 01 02 02 01 0C 30 0D 06
      09 2A 86 48 86 F7 0D 01 01 05 05 00 30 81 94 31 0B 30 09 06
      03 55 04 06 13 02 46 52 31 0F 30 0D 06 03 55 04 08 13 06 46
      72 61 6E 63 65 31 0E 30 0C 06 03 55 04 07 13 05 50 61 72 69
      73 31 13 30 11 06 03 55 04 0A 13 0A 45 74 68 65 72 54 90 00



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   // EAP-TLS ack
   >> A0 80 00 00 06 01 08 00 06 0D 00

   // 2nd EAP fragment
   << 02 08 00 86 0D 40 72 75 73 74 31 0D 30 0B 06 03 55 04 0B 13
      04 54 65 73 74 31 14 30 12 06 03 55 04 03 13 0B 50 61 73 63
      61 6C 55 72 69 65 6E 31 2A 30 28 06 09 2A 86 48 86 F7 0D 01
      09 01 16 1B 70 61 73 63 61 6C 2E 75 72 69 65 6E 40 65 74 68
      65 72 74 72 75 73 74 2E 63 6F 6D 30 1E 17 0D 31 34 30 37 31
      34 30 38 30 33 31 37 5A 17 0D 32 32 30 39 33 30 30 38 30 33
      31 37 5A 30 5D 31 0B 30 09 06 03 55 04 06
      90 00

   // EAP-TLS Ack
   >> A0 80 00 00 06 01 09 00 06 0D 00

   // 3rd EAP fragment
   << 02 09 00 86 0D 40 13 02 46 52 31 14 30 12 06 03 55 04 08 13
      0B 49 6C 65 44 65 46 72 61 6E 63 65 31 0E 30 0C 06 03 55 04
      07 13 05 50 61 72 69 73 31 17 30 15 06 03 55 04 0A 13 0E 65
      74 68 65 72 74 72 75 73 74 2E 63 6F 6D 31 0F 30 0D 06 03 55
      04 03 13 06 53 65 72 76 65 72 30 81 9F 30 0D 06 09 2A 86 48
      86 F7 0D 01 01 01 05 00 03 81 8D 00 30 81 89 02 81 81 00 D5
      E3 52 F5 55 2B 10 1D 7D E9 3F 1A 49 23 59
      90 00

   // EAP-TLS Ack
   >> A0 80 00 00 06 01 0A 00 06 0D 00

   // 4th EAP fragment
   << 02 0A 00 86 0D 40 8D F4 B2 E7 5C FE 4A 5B 0D D1 EA AB F2 A1
      6D 79 36 EA CC 06 E2 2B 4F C9 6C EB 7C 69 DB 22 BE B2 72 26
      26 A5 53 75 32 D4 80 7E CF AD 85 C1 B0 89 D4 35 FF B1 71 6B
      65 74 46 23 BD 52 B5 1B 90 D2 78 4B AF 1F EE C5 94 8D 9B 93
      55 70 4B 1B 5F E6 42 31 2D EA 48 BC C2 4E B4 CD C2 9F FF C2
      BE F2 D8 2B E2 99 AD 98 2E 22 EB 97 81 12 70 8E AF 37 29 02
      03 01 00 01 A3 0D 30 0B 30 09 06 03 55 1D
      90 00

   // EAP-TLS Ack
   >> A0 80 00 00 06 01 0B 00 06 0D 00

   // 5th EAP fragment
   << 02 0B 00 86 0D 40 13 04 02 30 00 30 0D 06 09 2A 86 48 86 F7
      0D 01 01 05 05 00 03 81 81 00 05 C2 17 66 F6 50 B5 BC EB 77
      CB 57 20 5A 46 9A FB FE 0B 53 1B E7 39 9F B4 8D FE A5 B8 5A
      5A 70 18 32 9C EE 0F 67 E8 F3 A2 61 94 5D A7 ED 89 F0 42 A3
      8C 85 CA 42 A9 94 49 C3 52 2C EF 9A 2E 64 DA BA B5 AE E9 29
      C4 F6 5D 7F E9 4D BF CF 7A D9 6D DE 22 3F E2 57 DF 50 B0 E3
      6E AD 69 4E 05 C8 B5 F7 DC FC 26 0D F8 B7
      90 00

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   // EAP-TLS Ack
   >> A0 80 00 00 06 01 0C 00 06 0D 00


   // 6th EAP fragment
   << 02 0C 00 86 0D 40 9A 9E B1 C3 9D 4C 4A C7 17 AB 72 18 80 84
      3F 71 4F CA 14 29 78 40 37 FF 10 00 00 82 00 03 00 00 00 00
      00 82 00 80 75 0B 3B E0 EC 77 E9 5E A0 4B A9 EE AE 1A B2 50
      37 13 3C 5A 93 8B A9 DD C1 9D 0F 50 21 9E 12 34 60 AA 74 BC
      AA 36 C7 41 D9 EA DE 25 6C A5 C7 43 F6 87 7A 4D 31 A0 50 D6
      B4 B9 F9 4E 6A FF D1 25 9A 62 18 43 54 3F 00 B6 31 21 C1 09
      28 9A BB 7B EE F0 62 92 5D E0 A3 9A CA E2
      90 00

   // EAP-TLS Ack
   >> A0 80 00 00 06 01 0D 00 06 0D 00

   // 7th EAP fragment
   << 02 0D 00 86 0D 40 51 EE 0A 87 85 36 BD 02 7A 40 B2 86 16 0E
      5E CE B5 E8 62 C0 3D F8 BC 2E F9 68 53 75 87 B7 AA 68 C8 EC
      65 AD 50 AD 0F 00 00 82 00 04 00 00 00 00 00 82 00 80 5A 35
      9C 84 56 48 04 91 2D EE 13 0D CB B1 C0 26 FE A9 37 40 B8 78
      A8 C5 06 27 94 2B 5D 04 65 2F 85 22 FB D7 56 04 72 C5 7B B4
      2D 41 E9 A9 4E 1D 14 1F F0 8C 83 40 FD 6A 84 39 49 E4 EF D6
      D1 8C 4E 7E 22 BD 96 5B 9B 2E 65 04 91 28
      90 00

   // EAP-TLS Ack
   >> A0 80 00 00 06 01 0E 00 06 0D 00

   // 8th EAP fragment
   << 02 0E 00 3A 0D 40 FE 91 4E 1A 1A 36 91 F1 05 12 C5 9D 78 11
      24 E6 65 44 E9 A2 80 4D F4 61 0C 79 5C 93 D5 B4 F0 29 47 DE
      50 91 77 6D 99 62 D8 3E 02 12 2C E0 75 BE A4 4F 1C B9
      90 00

   // EAP-TLS ack
   >> A0 80 00 00 06 01 0F 00 06 0D 00

   // 9th and last fragment
   << 02 0F 00 61 0D 00 14 FE FF 00 00 00 00 00 00 00 03 00 01 01
      16 FE FF 00 01 00 00 00 00 00 00 00 40 75 D7 8B EB FD 23 6F
      F7 63 65 D0 4C 40 1E F2 D5 9F 4D F0 D2 EA DF 6E F0 A8 89 7D
      15 86 B4 96 AB 93 61 9B 17 8D 01 50 64 C6 7C 76 BA 90 F7 22
      B3 D9 1A E3 B3 DA F4 43 1E 2C 3D 8B 49 02 D7 F6 6F
      90 00

   DTLS Bridge sends 664 bytes
   DTLS Bridge sends 155 bytes
   DTLS Bridge sends 155 bytes

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   DTLS Bridge sends 14 bytes
   DTLS Bridge sends 77 bytes

   DTLS Bridge receives
   RL-Seq=9, RL-epoch=0
   RL-Seq=0, RL-epoch=1

   // Flight 6
   // ChangeCipherSpec, Finished, in EAP-TLS Request
   >> A0 80 00 00 61 01 10 00 61 0D 00 14 FE FF 00 00 00 00 00 00
      00 09 00 01 01 16 FE FF 00 01 00 00 00 00 00 00 00 40 3F 2C
      D4 FE 86 92 89 66 C7 97 59 F1 C4 B8 15 C4 20 EC 39 FB B5 D5
      37 D9 86 72 37 95 DF 88 3A 22 A8 54 98 F0 BD 99 AF AC 37 62
      38 0C 86 4A 47 1B C0 63 08 CF 57 1B 5C DC 8C 7B C9 DB FE C0
      64 11

   // EAP-TLS Ack
   << 02 10 00 06 0D 00
      90 00

   TLS handshake completion


   // Process-EAP-Encrypt type=17h, payload = 16x AA

   >> A0 80 00 97 16 01 11 00 16 0D 00 AA AA AA AA AA AA AA AA AA
      AA AA AA AA AA AA AA

   // Encrypted DTLS Record Layer packet in EAP-Response
   << 02 11 00 57 0D 80 00 00 00 4D 17 FE FF 00 01 00 00 00 00 00
      01 00 40 2C E9 45 8E A9 44 FA 2B 13 75 A3 A3 63 01 F5 29 91
      8B 20 B1 9B E2 7D 30 2D 91 D1 32 9A 6F 2E 3E D1 7B 64 F0 2A
      06 3E C3 5E 34 81 A0 2D 6D C5 30 70 41 83 4A 1C 09 E6 93 66
      76 23 45 63 14 3E BB
      90 00

   Bridge sends 77 bytes
   Bridge receives RL-seq=1, RL-epoch=1

   //Process-EAP-Decrypt
   >> A0 80 00 00 53 01 12 00 53 0D 00 17 FE FF 00 01 00 00 00 00
      00 01 00 40 0F 0E EE 3C F7 F4 FF 87 03 22 53 93 53 0D 83 E8
      86 A5 F4 36 FB 94 B3 58 B3 A8 86 1A 29 B5 A8 BB 6A EA 8B ED
      B9 81 62 A4 96 57 7B 39 8E 55 E5 D1 0E DC 74 49 42 16 27 60
      C3 32 ED DA CC D3 42 4A

   // DTLS Record Layer Clear Payload = 16x AA
   << 02 12 00 1A 0D 80 00 00 00 10 AA AA AA AA AA AA AA AA AA AA
      AA AA AA AA AA AA
      90 00


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   // Process-EAP-Encrypt type=15h (Alert), payload = 0100
   >> A0 80 00 95 08 01 13 00 08 0D 00 01 00

   // Encrypted DTLS Record Layer packet in EAP-Response
   << 02 13 00 47 0D 80 00 00 00 3D 15 FE FF 00 01 00 00 00 00 00
      02 00 30 76 A5 73 71 9A 69 A3 8F DE 2F 0D 3D 15 49 D5 C1 01
      23 AE 0A 0B BB 14 F4 EC 8E 2E 84 A0 76 20 BF 3B 56 E7 C2 B9
      A4 0B 13 C2 71 BD AE C4 7F 95 32
      90 00

   Bridge sends 61 bytes
   Bridges receives RL-seq=2, RL-epoch=1

   //Process-EAP-Decrypt
   >> A0 80 00 00 43 01 14 00 43 0D 00 15 FE FF 00 01 00 00 00 00
      00 02 00 30 6B 4A 48 86 92 88 95 3C D9 0D 7B CD 9E 94 7B 93
      02 5C 75 FE C1 25 3E 5B 0D 99 8D 13 06 A3 3D 36 12 CD F9 1B
      23 0B CE 6E 55 E1 B1 9F 39 18 FA 10

   // DTLS Record Layer Clear Payload = 0100
   << 02 14 00 0C 0D 80 00 00 00 02 01 00
      90 00


8 Security Considerations


9 IANA Considerations


10 References


10.1 Normative References

   [TLS 1.0] Dierks, T., C. Allen, "The TLS Protocol Version 1.0", RFC
   2246, January 1999

   [TLS 1.1] Dierks, T., Rescorla, E., "The Transport Layer Security
   (TLS) Protocol Version 1.1", RFC 4346, April 2006

   [DTLS 1.0] E. Rescorla, N. Modadugu, " Datagram Transport Layer
   Security", RFC 4347, April 2006

   [EAP-TLS] D. Simon, B. Aboba, R. Hurst, "The EAP-TLS Authentication
   Protocol", RFC 5216, March 2008

   [TLS 1.2] Dierks, T., Rescorla, E., "The Transport Layer Security
   (TLS) Protocol Version 1.1", RFC 5746, August 2008



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                    TLS and DTLS Security Modules           June 2015

   [DTLS 1.2] E. Rescorla,  N. Modadugu "Datagram Transport Layer
   Security Version 1.2", RFC 6347, January 2012


   [COAP] Z. Shelby, K. Hartke, C. Bormann, "The Constrained
   Application Protocol (CoAP)", RFC 7252, June 2014

   [ISO7816] ISO 7816, "Cards Identification - Integrated Circuit Cards
   with Contacts", The International Organization for Standardization
   (ISO)

10.2 Informative References

   [EAP SC] Urien, P., "EAP Support in Smartcard", draft-urien-eap-
   smartcard-28.txt, December 2014


11 Authors' Addresses

   Pascal Urien
   Telecom ParisTech
   23 avenue d'Italie
   75013 Paris               Phone: NA
   France                    Email: Pascal.Urien@telecom-paristech.fr




























   Urien                   Expires December 2015            [Page 23]


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