Internet Engineering Task Force (IETF) J. Touch
Request for Comments: 5925 USC/ISI
Obsoletes: 2385 A. Mankin
Category: Standards Track Johns Hopkins Univ.
ISSN: 2070-1721 R. Bonica
Juniper Networks
June 2010
The TCP Authentication Option
Abstract
This document specifies the TCP Authentication Option (TCP-AO), which
obsoletes the TCP MD5 Signature option of RFC 2385 (TCP MD5). TCP-AO
specifies the use of stronger Message Authentication Codes (MACs),
protects against replays even for long-lived TCP connections, and
provides more details on the association of security with TCP
connections than TCP MD5. TCP-AO is compatible with either a static
Master Key Tuple (MKT) configuration or an external, out-of-band MKT
management mechanism; in either case, TCP-AO also protects
connections when using the same MKT across repeated instances of a
connection, using traffic keys derived from the MKT, and coordinates
MKT changes between endpoints. The result is intended to support
current infrastructure uses of TCP MD5, such as to protect long-lived
connections (as used, e.g., in BGP and LDP), and to support a larger
set of MACs with minimal other system and operational changes. TCP-
AO uses a different option identifier than TCP MD5, even though TCP-
AO and TCP MD5 are never permitted to be used simultaneously. TCP-AO
supports IPv6, and is fully compatible with the proposed requirements
for the replacement of TCP MD5.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc5925.
Touch, et al. Standards Track [Page 1]
RFC 5925 The TCP Authentication Option June 2010
Copyright Notice
Copyright (c) 2010 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.
Touch, et al. Standards Track [Page 2]
RFC 5925 The TCP Authentication Option June 2010
Table of Contents
1. Introduction ....................................................4
1.1. Conventions Used in This Document ..........................4
1.2. Applicability Statement ....................................5
1.3. Executive Summary ..........................................6
2. The TCP Authentication Option ...................................7
2.1. Review of TCP MD5 Option ...................................7
2.2. The TCP Authentication Option Format .......................8
3. TCP-AO Keys and Their Properties ...............................10
3.1. Master Key Tuple ..........................................10
3.2. Traffic Keys ..............................................12
3.3. MKT Properties ............................................13
4. Per-Connection TCP-AO Parameters ...............................14
5. Cryptographic Algorithms .......................................15
5.1. MAC Algorithms ............................................15
5.2. Traffic Key Derivation Functions ..........................18
5.3. Traffic Key Establishment and Duration Issues .............22
5.3.1. MKT Reuse Across Socket Pairs ......................22
5.3.2. MKTs Use within a Long-Lived Connection ............23
6. Additional Security Mechanisms .................................23
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