draft-ietf-ntp-mac-04.txt   draft-ietf-ntp-mac-05.txt 
Internet Engineering Task Force A. Malhotra Internet Engineering Task Force A. Malhotra
Internet-Draft S. Goldberg Internet-Draft S. Goldberg
Intended status: Standards Track Boston University Updates: 5905 (if approved) Boston University
Expires: September 6, 2018 March 5, 2018 Intended status: Standards Track October 3, 2018
Expires: April 6, 2019
Message Authentication Code for the Network Time Protocol Message Authentication Code for the Network Time Protocol
draft-ietf-ntp-mac-04 draft-ietf-ntp-mac-05
Abstract Abstract
RFC 5905 [RFC5905] states that Network Time Protocol (NTP) packets RFC 5905 [RFC5905] states that Network Time Protocol (NTP) packets
should be authenticated by appending a 128-bit key to the NTP data, should be authenticated by appending a 128-bit key to the NTP data,
and hashing the result with MD5 to obtain a 128-bit tag. This and hashing the result with MD5 to obtain a 128-bit tag. This
document deprecates MD5-based authentication, which is considered to document deprecates MD5-based authentication, which is considered to
be too weak, and recommends the use of AES-CMAC [RFC4493] as a be too weak, and recommends the use of AES-CMAC [RFC4493] as a
replacement. replacement.
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This Internet-Draft will expire on September 6, 2018. This Internet-Draft will expire on April 6, 2019.
Copyright Notice Copyright Notice
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document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. Deprecating MD5 . . . . . . . . . . . . . . . . . . . . . . . 2 2. Deprecating the use of MD5 . . . . . . . . . . . . . . . . . 2
3. Replacement Recommendation . . . . . . . . . . . . . . . . . 2 3. Replacement Recommendation . . . . . . . . . . . . . . . . . 2
4. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 3
5. Test Vectors . . . . . . . . . . . . . . . . . . . . . . . . 3 5. Test Vectors . . . . . . . . . . . . . . . . . . . . . . . . 3
6. Security Considerations . . . . . . . . . . . . . . . . . . . 3 6. Security Considerations . . . . . . . . . . . . . . . . . . . 3
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
9.1. Normative References . . . . . . . . . . . . . . . . . . 4 9.1. Normative References . . . . . . . . . . . . . . . . . . 4
9.2. Informative References . . . . . . . . . . . . . . . . . 4 9.2. Informative References . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
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document deprecates MD5-based authentication, which is considered to document deprecates MD5-based authentication, which is considered to
be too weak, and recommends the use of AES-CMAC [RFC4493] as a be too weak, and recommends the use of AES-CMAC [RFC4493] as a
replacement. replacement.
1.1. Requirements Language 1.1. Requirements Language
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 RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
2. Deprecating MD5 2. Deprecating the use of MD5
RFC 5905 [RFC5905] defines how the MD5 digest algorithm in RFC 1321 RFC 5905 [RFC5905] defines how the MD5 digest algorithm in RFC 1321
[RFC1321] can be used as a message authentication code (MAC) for [RFC1321] can be used as a message authentication code (MAC) for
authenticating NTP packets. However, as discussed in [BCK] and RFC authenticating NTP packets. However, as discussed in [BCK] and RFC
6151 [RFC6151], this is not a secure MAC and therefore MUST be 6151 [RFC6151], this is not a secure MAC and therefore MUST be
deprecated. deprecated.
3. Replacement Recommendation 3. Replacement Recommendation
If authentication is implemented, then AES-CMAC as specified in RFC If authentication is implemented, then AES-CMAC as specified in RFC
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