Ed25519 for DNSSEC
draft-sury-dnskey-ed25519-00
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
|
|
|---|---|---|---|
| Author | Ondřej Surý | ||
| Last updated | 2015-07-30 | ||
| Replaced by | draft-curdle-dnskey-ed25519, draft-ietf-curdle-dnskey-ed25519 | ||
| RFC stream | (None) | ||
| Formats | |||
| Additional resources | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-sury-dnskey-ed25519-00
Internet Engineering Task Force O. Sury
Internet-Draft CZ.NIC
Intended status: Standards Track July 30, 2015
Expires: January 31, 2016
Ed25519 for DNSSEC
draft-sury-dnskey-ed25519-00
Abstract
This document describes how to specify Ed25519 keys and signatures in
DNS Security (DNSSEC). It uses a Ed25519 curve and uses the SHA-256
for public key and SHA-512 hash for signatures.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 31, 2016.
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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. DNSKEY and RRSIG Resource Records for Ed25519 . . . . . . . . 3
3. Support for NSEC3 Denial of Existence . . . . . . . . . . . . 3
4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. Ed25519 Example . . . . . . . . . . . . . . . . . . . . . 4
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
DNSSEC, which is broadly defined in RFCs 4033 [RFC4033], 4034
[RFC4034], and 4035 [RFC4035],, uses cryptographic keys and digital
signatures to provide authentication of DNS data. Currently, the
most popular signature algorithm is RSA. RFC 6605 [RFC6605] defines
usage of Elliptic Curve Digital Signature Algorithm (ECDSA) for
DNSSEC with curve P-256 and SHA-256, and ECDSA with curve P-384 and
SHA-384.
This document defines the DNSKEY and RRSIG resource records (RRs) of
one new signing algorithm: curve Ed25519 and SHA-256. (A description
of Ed25519 can be found in EdDSA and Ed25519
[I-D.josefsson-eddsa-ed25519].) The DS RR for SHA-256 is already
defined in RFC 4509 [RFC4509].
Ed25519 is targeted to provide attack resistance comparable to
quality 128-bit symmetric ciphers that is equivalent strength of RSA
with 3072-bit keys. Public keys are 256 bits (32 bytes) in length
and signatures are 512 bits (64 bytes). Using Ed25519 curve in
DNSSEC has some advantages and disadvantage relative to using RSA
with SHA-256 and with 3072-bit keys. Ed25519 keys are much shorter
than RSA keys; at this size, the difference is 256 versus 3072 bits.
Similarly, Ed25519 signatures are much shorter than RSA signatures;
at this size, the difference is 512 versus vs 3072 bits. This is
relevant because DNSSEC stores and transmits both keys and
signatures.
In the signing algorithm defined in this document, the size of the
key for the elliptic curve is matched with the size of the output of
the hash algorithm (SHA-256). The size of the signatures are also
matched with size of the hashing algorithm (SHA-256).
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Signing with Ed25519 is significantly faster than with RSA (The
reference implementation signs 109000 messages per second on a quad-
core 2.4GHz Westmere CPU). However, validating RSA signatures is
significantly faster than validating Ed25519 signatures.
1.1. 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 [RFC2119].
2. DNSKEY and RRSIG Resource Records for Ed25519
The Ed25519 public keys consist of a 32-byte value that represents
encoding of the curve point. The generation of public key is defined
Chapter 5.5 in I-D.josefsson-eddsa-ed25519
[I-D.josefsson-eddsa-ed25519]. In DNSSEC keys, the Ed25519 public
key is a simple bit string that represents uncompressed form of a
curve point.
The Ed25519 signature constist of a 64-byte value. The Ed25519
signature algorithm is described Chapter 5.6 in I-D.josefsson-eddsa-
ed25519 [I-D.josefsson-eddsa-ed25519]. In DNSSEC keys, the Ed25519
signatures is a simple bit string that represents Ed25519 signature.
The algorithm number associated with the DNSKEY and RRSIG resource
records are fully defined in the IANA Considerations section. They
are:
o DNSKEY and RRSIG RRs signifying Ed25519 and SHA-512 use the
algorithm number TBD.
3. Support for NSEC3 Denial of Existence
RFC 5155 [RFC5155] defines new algorithm identifiers for existing
signing algorithms to indicate that zones signed with these algorithm
identifiers can use NSEC3 as well as NSEC records to provide denial
of existence. That mechanism was chosen to protect implementations
predating RFC 5155 from encountering resource records they could not
know about. This document does not define such algorithm aliases.
A DNSSEC validator that implements the signing algorithms defined in
this document MUST be able to validate negative answers in the form
of both NSEC and NSEC3 with hash algorithm 1, as defined in RFC 5155.
An authoritative server that does not implement NSEC3 MAY still serve
zones that use the signing algorithms defined in this document with
NSEC denial of existence.
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4. Examples
4.1. Ed25519 Example
This needs a real example - this copied example of P-256
Private-key-format: v1.2
Algorithm: TBD (Ed25519)
PrivateKey: ODIyNjAzODQ2MjgwODAxMjI2NDUxOTAyMDQxNDIyNjI= # coresponding to 82260384628080122645190204142262 INT
example.net. 3600 IN DNSKEY 257 3 13 (
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX== )
example.net. 3600 IN DS 55648 13 2 (
b4c8c1fe2e7477127b27115656ad6256f424625bf5c1
e2770ce6d6e37df61d17 )
www.example.net. 3600 IN A 192.0.2.1
www.example.net. 3600 IN RRSIG A 13 3 3600 (
20150909100439 20150812100439 55648 example.net.
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX== )
5. Acknowledgements
Some of the material in this document is copied liberally from RFC
6605 [RFC6605].
6. IANA Considerations
This document updates the IANA registry "Domain Name System Security
(DNSSEC) Algorithm Numbers". The following entry have been added to
the registry:
+--------------+----------------------+
| Number | TBD |
| Description | Ed25519 with SHA-512 |
| Mnemonic | Ed25519SHA512 |
| Zone Signing | Y |
| Trans. Sec. | * |
| Reference | This document |
+--------------+----------------------+
* There has been no determination of standardization of the use of
this algorithm with Transaction Security.
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7. Security Considerations
Ed25519 is targeted to provide attack resistance comparable to
quality 128-bit symmetric ciphers. Such an assessment could, of
course, change in the future if new attacks that work better than the
ones known today are found.
The security considerations listed in RFC 4509 apply here as well.
8. References
8.1. Normative References
[I-D.josefsson-eddsa-ed25519]
Josefsson, S. and N. Moller, "EdDSA and Ed25519", draft-
josefsson-eddsa-ed25519-03 (work in progress), May 2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "DNS Security Introduction and Requirements", RFC
4033, DOI 10.17487/RFC4033, March 2005,
<http://www.rfc-editor.org/info/rfc4033>.
[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Resource Records for the DNS Security Extensions",
RFC 4034, DOI 10.17487/RFC4034, March 2005,
<http://www.rfc-editor.org/info/rfc4034>.
[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Protocol Modifications for the DNS Security
Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,
<http://www.rfc-editor.org/info/rfc4035>.
[RFC5155] Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS
Security (DNSSEC) Hashed Authenticated Denial of
Existence", RFC 5155, DOI 10.17487/RFC5155, March 2008,
<http://www.rfc-editor.org/info/rfc5155>.
8.2. Informative References
[RFC4509] Hardaker, W., "Use of SHA-256 in DNSSEC Delegation Signer
(DS) Resource Records (RRs)", RFC 4509, DOI 10.17487/
RFC4509, May 2006,
<http://www.rfc-editor.org/info/rfc4509>.
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[RFC6605] Hoffman, P. and W. Wijngaards, "Elliptic Curve Digital
Signature Algorithm (DSA) for DNSSEC", RFC 6605, DOI
10.17487/RFC6605, April 2012,
<http://www.rfc-editor.org/info/rfc6605>.
Author's Address
Ondrej Sury
CZ.NIC
Milesovska 1136/5
Praha 130 00
CZ
Phone: +420 222 745 111
Email: ondrej.sury@nic.cz
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