< draft-ietf-ipsecme-chacha20-poly1305-00.txt   draft-ietf-ipsecme-chacha20-poly1305-01.txt >
Network Working Group Y. Nir Network Working Group Y. Nir
Internet-Draft Check Point Internet-Draft Check Point
Intended status: Standards Track March 30, 2015 Intended status: Standards Track March 31, 2015
Expires: October 1, 2015 Expires: October 2, 2015
ChaCha20, Poly1305 and their use in IPsec ChaCha20, Poly1305 and their use in IKE & IPsec
draft-ietf-ipsecme-chacha20-poly1305-00 draft-ietf-ipsecme-chacha20-poly1305-01
Abstract Abstract
This document describes the use of the ChaCha20 stream cipher along This document describes the use of the ChaCha20 stream cipher along
with the Poly1305 authenticator, combined into an AEAD algorithm for with the Poly1305 authenticator, combined into an AEAD algorithm for
IPsec. IPsec.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 1, 2015. This Internet-Draft will expire on October 2, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions Used in This Document . . . . . . . . . . . . 2 1.1. Conventions Used in This Document . . . . . . . . . . . . 2
2. ESP_ChaCha20-Poly1305 for ESP . . . . . . . . . . . . . . . . 3 2. ChaCha20 & Poly1305 for ESP . . . . . . . . . . . . . . . . . 3
2.1. AAD Construction . . . . . . . . . . . . . . . . . . . . 4 2.1. AAD Construction . . . . . . . . . . . . . . . . . . . . 4
3. Use in IKEv2 . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Use in IKEv2 . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 5 7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 5 7.2. Informative References . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
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only the best choice, but the only choice. only the best choice, but the only choice.
The problem is that if future advances in cryptanalysis reveal a The problem is that if future advances in cryptanalysis reveal a
weakness in AES, VPN users will be in an unenviable position. With weakness in AES, VPN users will be in an unenviable position. With
the only other widely supported cipher being the much slower 3DES, it the only other widely supported cipher being the much slower 3DES, it
is not feasible to re-configure IPsec installations to use 3DES. is not feasible to re-configure IPsec installations to use 3DES.
[standby-cipher] describes this issue and the need for a standby [standby-cipher] describes this issue and the need for a standby
cipher in greater detail. cipher in greater detail.
This document proposes the ChaCha20 stream cipher as such a standby This document proposes the ChaCha20 stream cipher as such a standby
cipher in an AEAD construction with the Poly1305 authenticator for cipher in an Authenticated Encryption with Associated Data (AEAD)
use with the Encapsulated Security Protocol (ESP - [RFC4303]) and the construction with the Poly1305 authenticator for use with the
Internet Key Exchange Protocol (IKEv2 - [RFC7296]). The algorithms Encapsulated Security Protocol (ESP - [RFC4303]) and the Internet Key
are described in a separate document ([chacha_poly]). This document Exchange Protocol (IKEv2 - [RFC7296]). The algorithms are described
only describes the IPsec-specific things. in a separate document ([chacha_poly]). This document only describes
the IPsec-specific things.
1.1. Conventions Used in This Document 1.1. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. ESP_ChaCha20-Poly1305 for ESP 2. ChaCha20 & Poly1305 for ESP
ESP_ChaCha20-Poly1305 is a combined mode algorithm, or AEAD. The AEAD_CHACHA20_POLY1305 is a combined mode algorithm, or AEAD. The
construction follows the AEAD construction in section 2.7 of construction follows the AEAD construction in section 2.7 of
[chacha_poly]: [chacha_poly]:
o The IV is 64-bit, and is used as part of the nonce. TBD: do we o The IV is 64-bit, and is used as part of the nonce. TBD: do we
want to skip the IV altogether and just use the packet counter? want to skip the IV altogether and just use the packet counter?
o A 32-bit sender ID is prepended to the 64-bit IV to form the o A 32-bit sender ID is prepended to the 64-bit IV to form the
96-bit nonce. For regular IPsec, this is set to all zeros. IPsec 96-bit nonce. For regular IPsec, this is set to all zeros. IPsec
extensions that allow multiple senders, such as GDOI ([RFC6407]) extensions that allow multiple senders, such as GDOI ([RFC6407])
or [RFC6054] may set this to different values. or [RFC6054] may set this to different values.
o The encryption key is 256-bit. o The encryption key is 256-bit.
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Another issue with implementing these algorithms is avoiding side Another issue with implementing these algorithms is avoiding side
channels. This is trivial for ChaCha20, but requires some care for channels. This is trivial for ChaCha20, but requires some care for
Poly1305. Considerations for implementations of these algorithms are Poly1305. Considerations for implementations of these algorithms are
in the [chacha_poly] document. in the [chacha_poly] document.
5. IANA Considerations 5. IANA Considerations
IANA is requested to assign one value from the IKEv2 "Transform Type IANA is requested to assign one value from the IKEv2 "Transform Type
1 - Encryption Algorithm Transform IDs" registry, with name 1 - Encryption Algorithm Transform IDs" registry, with name
ESP_ChaCha20-Poly1305, and this document as reference. ENCR_ChaCha20_Poly1305, and this document as reference.
6. Acknowledgements 6. Acknowledgements
All of the algorithms in this document were designed by D. J. All of the algorithms in this document were designed by D. J.
Bernstein. The AEAD construction was designed by Adam Langley. The Bernstein. The AEAD construction was designed by Adam Langley. The
author would also like to thank Adam for helpful comments, as well as author would also like to thank Adam for helpful comments, as well as
Yaron Sheffer for telling me to write the algorithms draft. Yaron Sheffer for telling me to write the algorithms draft.
7. References 7. References
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