An Interface and Algorithms for Authenticated Encryption
RFC 5116
| Document | Type |
RFC - Proposed Standard
(January 2008; Errata)
Was draft-mcgrew-auth-enc (individual in gen area)
|
|
|---|---|---|---|
| Last updated | 2015-10-14 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Reviews | |||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 5116 (Proposed Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Tim Polk | ||
| Send notices to | (None) | ||
Network Working Group D. McGrew
Request for Comments: 5116 Cisco Systems, Inc.
Category: Standards Track January 2008
An Interface and Algorithms for Authenticated Encryption
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Abstract
This document defines algorithms for Authenticated Encryption with
Associated Data (AEAD), and defines a uniform interface and a
registry for such algorithms. The interface and registry can be used
as an application-independent set of cryptoalgorithm suites. This
approach provides advantages in efficiency and security, and promotes
the reuse of crypto implementations.
McGrew Standards Track [Page 1]
RFC 5116 Authenticated Encryption January 2008
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Background . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3. Benefits . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4. Conventions Used in This Document . . . . . . . . . . . . 4
2. AEAD Interface . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1. Authenticated Encryption . . . . . . . . . . . . . . . . . 5
2.2. Authenticated Decryption . . . . . . . . . . . . . . . . . 7
2.3. Data Formatting . . . . . . . . . . . . . . . . . . . . . 7
3. Guidance on the Use of AEAD Algorithms . . . . . . . . . . . . 8
3.1. Requirements on Nonce Generation . . . . . . . . . . . . . 8
3.2. Recommended Nonce Formation . . . . . . . . . . . . . . . 9
3.2.1. Partially Implicit Nonces . . . . . . . . . . . . . . 10
3.3. Construction of AEAD Inputs . . . . . . . . . . . . . . . 11
3.4. Example Usage . . . . . . . . . . . . . . . . . . . . . . 11
4. Requirements on AEAD Algorithm Specifications . . . . . . . . 12
5. AEAD Algorithms . . . . . . . . . . . . . . . . . . . . . . . 14
5.1. AEAD_AES_128_GCM . . . . . . . . . . . . . . . . . . . . . 14
5.1.1. Nonce Reuse . . . . . . . . . . . . . . . . . . . . . 14
5.2. AEAD_AES_256_GCM . . . . . . . . . . . . . . . . . . . . . 15
5.3. AEAD_AES_128_CCM . . . . . . . . . . . . . . . . . . . . . 15
5.3.1. Nonce Reuse . . . . . . . . . . . . . . . . . . . . . 16
5.4. AEAD_AES_256_CCM . . . . . . . . . . . . . . . . . . . . . 16
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
7. Other Considerations . . . . . . . . . . . . . . . . . . . . . 17
8. Security Considerations . . . . . . . . . . . . . . . . . . . 18
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19
10.1. Normative References . . . . . . . . . . . . . . . . . . . 19
10.2. Informative References . . . . . . . . . . . . . . . . . . 19
McGrew Standards Track [Page 2]
RFC 5116 Authenticated Encryption January 2008
1. Introduction
Authenticated encryption [BN00] is a form of encryption that, in
addition to providing confidentiality for the plaintext that is
encrypted, provides a way to check its integrity and authenticity.
Authenticated Encryption with Associated Data, or AEAD [R02], adds
the ability to check the integrity and authenticity of some
Associated Data (AD), also called "additional authenticated data",
that is not encrypted.
1.1. Background
Many cryptographic applications require both confidentiality and
message authentication. Confidentiality is a security service that
ensures that data is available only to those authorized to obtain it;
usually it is realized through encryption. Message authentication is
the service that ensures that data has not been altered or forged by
unauthorized entities; it can be achieved by using a Message
Authentication Code (MAC). This service is also called data
integrity. Many applications use an encryption method and a MAC
together to provide both of those security services, with each
algorithm using an independent key. More recently, the idea of
providing both security services using a single cryptoalgorithm has
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