The PPP DES Encryption Protocol, Version 2 (DESE-bis)
RFC 2419
Document | Type |
RFC - Proposed Standard
(September 1998; No errata)
Obsoletes RFC 1969
|
|
---|---|---|---|
Authors | Gerry Meyer , Keith Sklower | ||
Last updated | 2013-03-02 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 2419 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group K. Sklower Request for Comments: 2419 University of California, Berkeley Obsoletes: 1969 G. Meyer Category: Standards Track Shiva September 1998 The PPP DES Encryption Protocol, Version 2 (DESE-bis) Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (1998). All Rights Reserved. Abstract The Point-to-Point Protocol (PPP) [1] provides a standard method for transporting multi-protocol datagrams over point-to-point links. The PPP Encryption Control Protocol (ECP) [2] provides a method to negotiate and utilize encryption protocols over PPP encapsulated links. This document provides specific details for the use of the DES standard [5, 6] for encrypting PPP encapsulated packets. Acknowledgements The authors extend hearty thanks to Fred Baker of Cisco, Philip Rakity of Flowpoint, and William Simpson of Daydreamer for helpful improvements to the clarity and correctness of the document. Table of Contents 1. Introduction ................................................ 2 1.1. Motivation ................................................ 2 1.2. Conventions ............................................... 2 2. General Overview ............................................ 2 3. Structure of This Specification ............................. 4 4. DESE Configuration Option for ECP ........................... 4 5. Packet Format for DESE ...................................... 5 Sklower & Meyer Standards Track [Page 1] RFC 2419 PPP DES Encryption v2 September 1998 6. Encryption .................................................. 6 6.1. Padding Considerations .................................... 7 6.2. Generation of the Ciphertext .............................. 8 6.3. Retrieval of the Plaintext ................................ 8 6.4. Recovery after Packet Loss ................................ 8 7. MRU Considerations .......................................... 9 8. Differences from RFC 1969 ................................... 9 8.1. When to Pad ............................................... 9 8.2. Assigned Numbers .......................................... 9 8.3. Minor Editorial Changes ................................... 9 9. Security Considerations ..................................... 9 10. References ................................................. 10 11. Authors' Addresses ......................................... 11 12. Full Copyright Statement ................................... 12 1. Introduction 1.1. Motivation The purpose of this memo is two-fold: to show how one specifies the necessary details of a "data" or "bearer" protocol given the context of the generic PPP Encryption Control Protocol, and also to provide at least one commonly-understood means of secure data transmission between PPP implementations. The DES encryption algorithm is a well studied, understood and widely implemented encryption algorithm. The DES cipher was designed for efficient implementation in hardware, and consequently may be relatively expensive to implement in software. However, its pervasiveness makes it seem like a reasonable choice for a "model" encryption protocol. Source code implementing DES in the "Electronic Code Book Mode" can be found in [7]. US export laws forbid the inclusion of compilation-ready source code in this document. 1.2. 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 RFC 2119 [8]. 2. General Overview The purpose of encrypting packets exchanged between two PPP implementations is to attempt to insure the privacy of communication conducted via the two implementations. The encryption process depends on the specification of an encryption algorithm and a shared Sklower & Meyer Standards Track [Page 2] RFC 2419 PPP DES Encryption v2 September 1998 secret (usually involving at least a key) between the sender and receiver. Generally, the encryptor will take a PPP packet including the protocol field, apply the chosen encryption algorithm, place theShow full document text