draft-ietf-dnsext-dnssec-rsasha256-12.txt   draft-ietf-dnsext-dnssec-rsasha256-13.txt 
DNS Extensions working group J. Jansen DNS Extensions working group J. Jansen
Internet-Draft NLnet Labs Internet-Draft NLnet Labs
Intended status: Standards Track March 23, 2009 Intended status: Standards Track April 24, 2009
Expires: September 24, 2009 Expires: October 26, 2009
Use of SHA-2 algorithms with RSA in DNSKEY and RRSIG Resource Records Use of SHA-2 algorithms with RSA in DNSKEY and RRSIG Resource Records
for DNSSEC for DNSSEC
draft-ietf-dnsext-dnssec-rsasha256-12 draft-ietf-dnsext-dnssec-rsasha256-13
Status of this Memo Status of this Memo
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Copyright Notice Copyright Notice
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Abstract Abstract
This document describes how to produce RSA/SHA-256 and RSA/SHA-512 This document describes how to produce RSA/SHA-256 and RSA/SHA-512
DNSKEY and RRSIG resource records for use in the Domain Name System DNSKEY and RRSIG resource records for use in the Domain Name System
Security Extensions (DNSSEC, RFC 4033, RFC 4034, and RFC 4035). Security Extensions (DNSSEC, RFC 4033, RFC 4034, and RFC 4035).
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. DNSKEY Resource Records . . . . . . . . . . . . . . . . . . . . 3 2. DNSKEY Resource Records . . . . . . . . . . . . . . . . . . . 3
2.1. RSA/SHA-256 DNSKEY Resource Records . . . . . . . . . . . . 3 2.1. RSA/SHA-256 DNSKEY Resource Records . . . . . . . . . . . 3
2.2. RSA/SHA-512 DNSKEY Resource Records . . . . . . . . . . . . 4 2.2. RSA/SHA-512 DNSKEY Resource Records . . . . . . . . . . . 4
3. RRSIG Resource Records . . . . . . . . . . . . . . . . . . . . 4 3. RRSIG Resource Records . . . . . . . . . . . . . . . . . . . . 4
3.1. RSA/SHA-256 RRSIG Resource Records . . . . . . . . . . . . 4 3.1. RSA/SHA-256 RRSIG Resource Records . . . . . . . . . . . . 4
3.2. RSA/SHA-512 RRSIG Resource Records . . . . . . . . . . . . 5 3.2. RSA/SHA-512 RRSIG Resource Records . . . . . . . . . . . . 5
4. Deployment Considerations . . . . . . . . . . . . . . . . . . . 5 4. Deployment Considerations . . . . . . . . . . . . . . . . . . 5
4.1. Key Sizes . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.1. Key Sizes . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. Signature Sizes . . . . . . . . . . . . . . . . . . . . . . 5 4.2. Signature Sizes . . . . . . . . . . . . . . . . . . . . . 5
5. Implementation Considerations . . . . . . . . . . . . . . . . . 5 5. Implementation Considerations . . . . . . . . . . . . . . . . 5
5.1. Support for SHA-2 signatures . . . . . . . . . . . . . . . 5 5.1. Support for SHA-2 signatures . . . . . . . . . . . . . . . 5
5.2. Support for NSEC3 Denial of Existence . . . . . . . . . . . 5 5.2. Support for NSEC3 Denial of Existence . . . . . . . . . . 5
5.2.1. NSEC3 in Authoritative servers . . . . . . . . . . . . 6 6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.2.2. NSEC3 in Validators . . . . . . . . . . . . . . . . . . 6 6.1. RSA/SHA-256 Key and Signature . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 6.2. RSA/SHA-512 Key and Signature . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
7.1. SHA-1 versus SHA-2 Considerations for RRSIG Resource 8. Security Considerations . . . . . . . . . . . . . . . . . . . 8
Records . . . . . . . . . . . . . . . . . . . . . . . . . . 6 8.1. SHA-1 versus SHA-2 Considerations for RRSIG Resource
7.2. Signature Type Downgrade Attacks . . . . . . . . . . . . . 7 Records . . . . . . . . . . . . . . . . . . . . . . . . . 8
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7 8.2. Signature Type Downgrade Attacks . . . . . . . . . . . . . 8
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9
9.1. Normative References . . . . . . . . . . . . . . . . . . . 7 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
9.2. Informative References . . . . . . . . . . . . . . . . . . 8 10.1. Normative References . . . . . . . . . . . . . . . . . . . 9
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 8 10.2. Informative References . . . . . . . . . . . . . . . . . . 9
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction 1. Introduction
The Domain Name System (DNS) is the global hierarchical distributed The Domain Name System (DNS) is the global hierarchical distributed
database for Internet Naming. The DNS has been extended to use database for Internet Naming. The DNS has been extended to use
cryptographic keys and digital signatures for the verification of the cryptographic keys and digital signatures for the verification of the
authenticity and integrity of its data. RFC 4033 [RFC4033], RFC 4034 authenticity and integrity of its data. RFC 4033 [RFC4033], RFC 4034
[RFC4034], and RFC 4035 [RFC4035] describe these DNS Security [RFC4034], and RFC 4035 [RFC4035] describe these DNS Security
Extensions, called DNSSEC. Extensions, called DNSSEC.
skipping to change at page 5, line 48 skipping to change at page 5, line 48
defined in this document. defined in this document.
5.2. Support for NSEC3 Denial of Existence 5.2. Support for NSEC3 Denial of Existence
RFC 5155 [RFC5155] defines new algorithm identifiers for existing RFC 5155 [RFC5155] defines new algorithm identifiers for existing
signing algorithms, to indicate that zones signed with these signing algorithms, to indicate that zones signed with these
algorithm identifiers can use NSEC3 as well as NSEC records to algorithm identifiers can use NSEC3 as well as NSEC records to
provide denial of existence. That mechanism was chosen to protect provide denial of existence. That mechanism was chosen to protect
implementations predating RFC5155 from encountering resource records implementations predating RFC5155 from encountering resource records
they could not know about. This document does not define such they could not know about. This document does not define such
algorithm aliases, and support for NSEC3 denial of existence is algorithm aliases.
implicitly signaled with support for one of the algorithms defined in
this document.
5.2.1. NSEC3 in Authoritative servers A DNSSEC validator that implements RSA/SHA-2 MUST be able to validate
both NSEC and NSEC3 [RFC5155] negative answers. An authoritative
server that does not implement NSEC3 MAY still serve zones that use
RSA/SHA-2 with NSEC denial of existence.
An authoritative server that does not implement NSEC3 MAY still serve 6. Examples
zones that use RSA/SHA-2 with NSEC denial of existence.
5.2.2. NSEC3 in Validators 6.1. RSA/SHA-256 Key and Signature
A DNSSEC validator that implements RSA/SHA-2 MUST be able to handle Given a private key with the following values (in Base64):
both NSEC and NSEC3 [RFC5155] negative answers. If this is not the
case, the validator MUST treat a zone signed with RSA/SHA-256 or RSA/
SHA-512 as signed with an unknown algorithm, and thus as insecure.
6. IANA Considerations Private-key-format: v1.2
Algorithm: 8 (RSASHA256)
Modulus: wVwaxrHF2CK64aYKRUibLiH30KpPuPBjel7E8ZydQW1HYWHfoGm
idzC2RnhwCC293hCzw+TFR2nqn8OVSY5t2Q==
PublicExponent: AQAB
PrivateExponent: UR44xX6zB3eaeyvTRzmskHADrPCmPWnr8dxsNwiDGHzrMKLN+i/
HAam+97HxIKVWNDH2ba9Mf1SA8xu9dcHZAQ==
Prime1: 4c8IvFu1AVXGWeFLLFh5vs7fbdzdC6U82fduE6KkSWk=
Prime2: 2zZpBE8ZXVnL74QjG4zINlDfH+EOEtjJJ3RtaYDugvE=
Exponent1: G2xAPFfK0KGxGANDVNxd1K1c9wOmmJ51mGbzKFFNMFk=
Exponent2: GYxP1Pa7CAwtHm8SAGX594qZVofOMhgd6YFCNyeVpKE=
Coefficient: icQdNRjlZGPmuJm2TIadubcO8X7V4y07aVhX464tx8Q=
The DNSKEY record for this key would be:
example.net. 3600 IN DNSKEY (256 3 8 AwEAAcFcGsaxxdgiuuGmCkVI
my4h99CqT7jwY3pexPGcnUFtR2Fh36BponcwtkZ4cAgtvd4Qs8P
kxUdp6p/DlUmObdk= );{id = 9033 (zsk), size = 512b}
With this key, sign the following RRSet, consisting of 1 A record:
www.example.net. 3600 IN A 123.123.123.123
If the inception date is set at 00:00 hours on January 1st, 2000, and
the expiration date at 00:00 hours on January 1st, 2030, the
following signature should be created:
www.example.net. 3600 IN RRSIG (A 8 3 3600 20300101000000
20000101000000 9033 example.net. KWgSIg3khRfyrHmtJU
5pzpsANyy27+HOZ6waMQ5kV690ljVmbHmGc8ULOfXw3aWmP0wJB
ND/TQhjCvrb3T9ffQ== );{id = 9033}
6.2. RSA/SHA-512 Key and Signature
Given a private key with the following values (in Base64):
Private-key-format: v1.2
Algorithm: 9 (RSASHA512)
Modulus: 8Du9YHEwFNjO5iG9jrrNyKwRs5mAzJgXBrjbA49R/ESWJKw6eHH
XfZaxnP+gVhZBDmqwND/SFwrEkN5LyH3HZ+/d/ECW+vT8Lxprqf
haTfxQkV4OFjw/ikuTcBMoUIYfhO1NVPBcH1mWh34DWmu6eedzH
IbdeNZnIkWSv4muchs=
PublicExponent: AQAB
PrivateExponent: sRm5YLHQ2m2DCdDx55j7P+bqHdcaRroQr5nzi8pKjIkbjumRKV3
zmNhRFAa3cv9w8mnggIRUIzyC8LGQeLuRFjbv6uXDzoPX2O321j
PlTUOwCYMTVnbkZUem6c+7iRd2v5zNNe9uiXex6T8CDXyhQhqYb
8q2AajPrTlRzv6uW8E=
Prime1: +DPVg2OlfYqcNlm67T42608gjyqWFdVc0UtDDDBo+ABWavqp+Yk
Fb/z/Ig+iBE901Q8RWdqVLND3PtGwWipIyw==
Prime2: 98fQbOaWH3D/WFhnu47f1qOgaob/ss3FQ12QbUdRDpgfmdryHH7
j1UGR2Xs0aRPwBASXYhgtamXtxLorXIFh8Q==
Exponent1: j0UsbGlqr6sBPQZStnuBLBdCziFg/T1qFI4DJ9gR34YiXCJRV29
Wqiw6AalQdnh/EjVeaKWaEoKVFbfoukNKPQ==
Exponent2: 4YTy9ftVjd5p+f3UxEgBATnCatLebd6NeYfySRQM+YyJzp4RmNA
BC/t3BQv3IuBrpyyKoFTDGUEWjOSpTLPR8Q==
Coefficient: BpIAEwh5rlw9M8FpGHjpF5TxSdhCjnA8NT0tB+MB/k0msceyBbx
avjzJXTi/QPk9PIO8Wv6eCzMQEM0QDZO53Q==
The DNSKEY record for this key would be:
example.net. 3600 IN DNSKEY (256 3 9 AwEAAfA7vWBxMBTYzuYhvY66z
cisEbOZgMyYFwa42wOPUfxEliSsOnhx132WsZz/oFYWQQ5qsDQ/0
hcKxJDeS8h9x2fv3fxAlvr0/C8aa6n4Wk38UJFeDhY8P4pLk3ATK
FCGH4TtTVTwXB9Zlod+A1prunnncxyG3XjWZyJFkr+JrnIb
);{id = 28237 (zsk), size = 1024b}
With this key, sign the following RRSet, consisting of 1 A record:
www.example.net. 3600 IN A 123.123.123.123
If the inception date is set at 00:00 hours on January 1st, 2000, and
the expiration date at 00:00 hours on January 1st, 2030, the
following signature should be created:
www.example.net. 3600 IN RRSIG (A 9 3 3600 20300101000000
20000101000000 28237 example.net. mCanSdkQztEUOmslG
z7VvfkKPMp4ftz3K1PTf2jdla4vUu/tRE585xymurMB+wXhrFcK
dhm0egnPq8X/gmm0cmui/GQwFT5hmP5bL1ETuQsM3HOu3j9E3tq
4sFWIsUv3N6ohpYEbhj5jk0b/01EMUPM9y5rLzFHmYYujzKQwqu
M= );{id = 28237}
7. IANA Considerations
This document updates the IANA registry "DNS SECURITY ALGORITHM This document updates the IANA registry "DNS SECURITY ALGORITHM
NUMBERS -- per [RFC4035] " NUMBERS -- per [RFC4035] "
(http://www.iana.org/assignments/dns-sec-alg-numbers). The following (http://www.iana.org/assignments/dns-sec-alg-numbers). The following
entries are added to the registry: entries are added to the registry:
Zone Trans. Zone Trans.
Value Description Mnemonic Signing Sec. References Value Description Mnemonic Signing Sec. References
{TBA1} RSA/SHA-256 RSASHA256 y * {this memo} {TBA1} RSA/SHA-256 RSASHA256 y * {this memo}
{TBA2} RSA/SHA-512 RSASHA512 y * {this memo} {TBA2} RSA/SHA-512 RSASHA512 y * {this memo}
* There has been no determination of standardization of the use of this * There has been no determination of standardization of the use of this
algorithm with Transaction Security. algorithm with Transaction Security.
7. Security Considerations 8. Security Considerations
7.1. SHA-1 versus SHA-2 Considerations for RRSIG Resource Records 8.1. SHA-1 versus SHA-2 Considerations for RRSIG Resource Records
Users of DNSSEC are encouraged to deploy SHA-2 as soon as software Users of DNSSEC are encouraged to deploy SHA-2 as soon as software
implementations allow for it. SHA-2 is widely believed to be more implementations allow for it. SHA-2 is widely believed to be more
resilient to attack than SHA-1, and confidence in SHA-1's strength is resilient to attack than SHA-1, and confidence in SHA-1's strength is
being eroded by recently-announced attacks. Regardless of whether or being eroded by recently-announced attacks. Regardless of whether or
not the attacks on SHA-1 will affect DNSSEC, it is believed (at the not the attacks on SHA-1 will affect DNSSEC, it is believed (at the
time of this writing) that SHA-2 is the better choice for use in time of this writing) that SHA-2 is the better choice for use in
DNSSEC records. DNSSEC records.
SHA-2 is considered sufficiently strong for the immediate future, but SHA-2 is considered sufficiently strong for the immediate future, but
predictions about future development in cryptography and predictions about future development in cryptography and
cryptanalysis are beyond the scope of this document. cryptanalysis are beyond the scope of this document.
The signature scheme RSASSA-PKCS1-v1_5 is chosen to match the one The signature scheme RSASSA-PKCS1-v1_5 is chosen to match the one
used for RSA/SHA-1 signatures. This should ease implementation of used for RSA/SHA-1 signatures. This should ease implementation of
the new hashing algorithms in DNSSEC software. the new hashing algorithms in DNSSEC software.
7.2. Signature Type Downgrade Attacks 8.2. Signature Type Downgrade Attacks
Since each RRSet MUST be signed with each algorithm present in the Since each RRSet MUST be signed with each algorithm present in the
DNSKEY RRSet at the zone apex (see [RFC4035] Section 2.2), a DNSKEY RRSet at the zone apex (see [RFC4035] Section 2.2), a
malicious party cannot filter out the RSA/SHA-2 RRSIG, and force the malicious party cannot filter out the RSA/SHA-2 RRSIG, and force the
validator to use the RSA/SHA-1 signature if both are present in the validator to use the RSA/SHA-1 signature if both are present in the
zone. This should provide resilience against algorithm downgrade zone. This should provide resilience against algorithm downgrade
attacks, if the validator supports RSA/SHA-2. attacks, if the validator supports RSA/SHA-2.
8. Acknowledgments 9. Acknowledgments
This document is a minor extension to RFC 4034 [RFC4034]. Also, we This document is a minor extension to RFC 4034 [RFC4034]. Also, we
try to follow the documents RFC 3110 [RFC3110] and RFC 4509 [RFC4509] try to follow the documents RFC 3110 [RFC3110] and RFC 4509 [RFC4509]
for consistency. The authors of and contributors to these documents for consistency. The authors of and contributors to these documents
are gratefully acknowledged for their hard work. are gratefully acknowledged for their hard work.
The following people provided additional feedback and text: Jaap The following people provided additional feedback and text: Jaap
Akkerhuis, Mark Andrews, Roy Arends, Rob Austein, Francis Dupont, Akkerhuis, Mark Andrews, Roy Arends, Rob Austein, Francis Dupont,
Miek Gieben, Alfred Hoenes, Paul Hoffman, Peter Koch, Michael St. Miek Gieben, Alfred Hoenes, Paul Hoffman, Peter Koch, Michael St.
Johns, Scott Rose and Wouter Wijngaards. Johns, Scott Rose and Wouter Wijngaards.
9. References 10. References
9.1. Normative References 10.1. Normative References
[FIPS.180-3.2008] [FIPS.180-3.2008]
National Institute of Standards and Technology, "Secure National Institute of Standards and Technology, "Secure
Hash Standard", FIPS PUB 180-3, October 2008. Hash Standard", FIPS PUB 180-3, October 2008.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997. Requirement Levels", RFC 2119, March 1997.
[RFC3110] Eastlake, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain [RFC3110] Eastlake, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain
Name System (DNS)", RFC 3110, May 2001. Name System (DNS)", RFC 3110, May 2001.
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RFC 4033, March 2005. RFC 4033, March 2005.
[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Resource Records for the DNS Security Extensions", Rose, "Resource Records for the DNS Security Extensions",
RFC 4034, March 2005. RFC 4034, March 2005.
[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. [RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Protocol Modifications for the DNS Security Rose, "Protocol Modifications for the DNS Security
Extensions", RFC 4035, March 2005. Extensions", RFC 4035, March 2005.
9.2. Informative References 10.2. Informative References
[NIST800-57] [NIST800-57]
Barker, E., Barker, W., Burr, W., Polk, W., and M. Smid, Barker, E., Barker, W., Burr, W., Polk, W., and M. Smid,
"Recommendations for Key Management", NIST SP 800-57, "Recommendations for Key Management", NIST SP 800-57,
March 2007. March 2007.
[RFC3447] Jonsson, J. and B. Kaliski, "Public-Key Cryptography [RFC3447] Jonsson, J. and B. Kaliski, "Public-Key Cryptography
Standards (PKCS) #1: RSA Cryptography Specifications Standards (PKCS) #1: RSA Cryptography Specifications
Version 2.1", RFC 3447, February 2003. Version 2.1", RFC 3447, February 2003.
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