AES Encryption with HMAC-SHA2 for Kerberos 5
draft-ietf-kitten-aes-cts-hmac-sha2-08
Network Working Group M. Jenkins
Internet Draft National Security Agency
Intended Status: Informational M. Peck
Expires: June 11, 2016 The MITRE Corporation
K. Burgin
December 9, 2015
AES Encryption with HMAC-SHA2 for Kerberos 5
draft-ietf-kitten-aes-cts-hmac-sha2-08
Abstract
This document specifies two encryption types and two corresponding
checksum types for Kerberos 5. The new types use AES in CTS mode
(CBC mode with ciphertext stealing) for confidentiality and HMAC with
a SHA-2 hash for integrity.
Status of this Memo
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This Internet-Draft will expire on June 11, 2016.
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Internet-Draft AES-CTS HMAC-SHA2 For Kerberos 5 December 9, 2015
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Protocol Key Representation . . . . . . . . . . . . . . . . . 3
3. Key Derivation Function . . . . . . . . . . . . . . . . . . . 3
4. Key Generation from Pass Phrases . . . . . . . . . . . . . . . 4
5. Kerberos Algorithm Protocol Parameters . . . . . . . . . . . . 5
6. Checksum Parameters . . . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
8. Security Considerations . . . . . . . . . . . . . . . . . . . 8
8.1. Random Values in Salt Strings . . . . . . . . . . . . . . 8
8.2. Algorithm Rationale . . . . . . . . . . . . . . . . . . . 9
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
10.1. Normative References . . . . . . . . . . . . . . . . . . 9
10.2. Informative References . . . . . . . . . . . . . . . . . 9
Appendix A. Test Vectors . . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17
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Internet-Draft AES-CTS HMAC-SHA2 For Kerberos 5 December 9, 2015
1. Introduction
This document defines two encryption types and two corresponding
checksum types for Kerberos 5 using AES with 128-bit or 256-bit keys.
To avoid ciphertext expansion, we use a variation of the CBC-CS3 mode
defined in [SP800-38A+], also referred to as ciphertext stealing or
CTS mode. The new types conform to the framework specified in
[RFC3961], but do not use the simplified profile.
The encryption and checksum types defined in this document are
intended to support environments that desire to use SHA-256 or SHA-
384 as the hash algorithm. Differences between the encryption and
checksum types defined in this document and the pre-existing Kerberos
AES encryption and checksum types specified in [RFC3962] are:
* The pseudorandom function used by PBKDF2 is HMAC-SHA-256 or HMAC-
SHA-384.
* A key derivation function from [SP800-108] using the SHA-256 or
SHA-384 hash algorithm is used to produce keys for encryption,
integrity protection, and checksum operations.
* The HMAC is calculated over the cipherstate concatenated with the
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