ChaCha20-Poly1305 Cipher Suites for Transport Layer Security (TLS)
RFC 7905
Internet Engineering Task Force (IETF) A. Langley
Request for Comments: 7905 W. Chang
Updates: 5246, 6347 Google, Inc.
Category: Standards Track N. Mavrogiannopoulos
ISSN: 2070-1721 Red Hat
J. Strombergson
Secworks Sweden AB
S. Josefsson
SJD AB
June 2016
ChaCha20-Poly1305 Cipher Suites for Transport Layer Security (TLS)
Abstract
This document describes the use of the ChaCha stream cipher and
Poly1305 authenticator in the Transport Layer Security (TLS) and
Datagram Transport Layer Security (DTLS) protocols.
This document updates RFCs 5246 and 6347.
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 7841.
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/rfc7905.
Langley, et al. Standards Track [Page 1]
RFC 7905 ChaCha-Poly1305 for TLS June 2016
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. 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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. ChaCha20 Cipher Suites . . . . . . . . . . . . . . . . . . . 4
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.1. Normative References . . . . . . . . . . . . . . . . . . 6
5.2. Informative References . . . . . . . . . . . . . . . . . 6
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
Langley, et al. Standards Track [Page 2]
RFC 7905 ChaCha-Poly1305 for TLS June 2016
1. Introduction
This document describes the use of the ChaCha stream cipher and
Poly1305 authenticator in version 1.2 or later of the Transport Layer
Security (TLS) protocol [RFC5246] as well as version 1.2 or later of
the Datagram Transport Layer Security (DTLS) protocol [RFC6347].
ChaCha [CHACHA] is a stream cipher developed by D. J. Bernstein in
2008. It is a refinement of Salsa20, which is one of the selected
ciphers in the eSTREAM portfolio [ESTREAM], and it was used as the
core of the SHA-3 finalist, BLAKE.
The variant of ChaCha used in this document has 20 rounds, a 96-bit
nonce, and a 256-bit key; it is referred to as "ChaCha20". This is
the conservative variant (with respect to security) of the ChaCha
family and is described in [RFC7539].
Poly1305 [POLY1305] is a Wegman-Carter, one-time authenticator
designed by D. J. Bernstein. Poly1305 takes a 256-bit, one-time key
and a message, and it produces a 16-byte tag that authenticates the
message such that an attacker has a negligible chance of producing a
valid tag for an inauthentic message. It is described in [RFC7539].
ChaCha and Poly1305 have both been designed for high performance in
software implementations. They typically admit a compact
implementation that uses few resources and inexpensive operations,
which makes them suitable on a wide range of architectures. They
have also been designed to minimize leakage of information through
side-channels.
Recent attacks [CBC-ATTACK] have indicated problems with the CBC-mode
cipher suites in TLS and DTLS, as well as issues with the only
Show full document text