Re-keying Mechanisms for Symmetric Keys
RFC 8645
| Document | Type |
RFC - Informational
(August 2019; No errata)
Was draft-irtf-cfrg-re-keying (cfrg RG)
|
|
|---|---|---|---|
| Last updated | 2019-08-29 | ||
| Replaces | draft-cfrg-re-keying | ||
| Stream | IRTF | ||
| Formats | plain text pdf htmlized bibtex | ||
| IETF conflict review | conflict-review-irtf-cfrg-re-keying | ||
| Stream | IRTF state | Published RFC | |
| Consensus Boilerplate | Yes | ||
| Document shepherd | Alexey Melnikov | ||
| Shepherd write-up | Show (last changed 2019-05-15) | ||
| IESG | IESG state | RFC 8645 (Informational) | |
| Telechat date | |||
| Responsible AD | (None) | ||
| Send notices to | Alexey Melnikov <alexey.melnikov@isode.com> | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | No IANA Actions | ||
Internet Research Task Force (IRTF) S. Smyshlyaev, Ed.
Request for Comments: 8645 CryptoPro
Category: Informational August 2019
ISSN: 2070-1721
Re-keying Mechanisms for Symmetric Keys
Abstract
A certain maximum amount of data can be safely encrypted when
encryption is performed under a single key. This amount is called
the "key lifetime". This specification describes a variety of
methods for increasing the lifetime of symmetric keys. It provides
two types of re-keying mechanisms based on hash functions and block
ciphers that can be used with modes of operations such as CTR, GCM,
CBC, CFB, and OMAC.
This document is a product of the Crypto Forum Research Group (CFRG)
in the IRTF.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Research Task Force
(IRTF). The IRTF publishes the results of Internet-related research
and development activities. These results might not be suitable for
deployment. This RFC represents the consensus of the Crypto Forum
Research Group of the Internet Research Task Force (IRTF). Documents
approved for publication by the IRSG are not candidates for any level
of Internet Standard; see Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8645.
Smyshlyaev Informational [Page 1]
RFC 8645 Re-keying Mechanisms for Symmetric Keys August 2019
Copyright Notice
Copyright (c) 2019 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
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document.
Smyshlyaev Informational [Page 2]
RFC 8645 Re-keying Mechanisms for Symmetric Keys August 2019
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Conventions Used in This Document . . . . . . . . . . . . . . 7
3. Basic Terms and Definitions . . . . . . . . . . . . . . . . . 7
4. Choosing Constructions and Security Parameters . . . . . . . 9
5. External Re-keying Mechanisms . . . . . . . . . . . . . . . . 11
5.1. Methods of Key Lifetime Control . . . . . . . . . . . . . 14
5.2. Parallel Constructions . . . . . . . . . . . . . . . . . 14
5.2.1. Parallel Construction Based on a KDF on a Block
Cipher . . . . . . . . . . . . . . . . . . . . . . . 15
5.2.2. Parallel Construction Based on a KDF on a Hash
Function . . . . . . . . . . . . . . . . . . . . . . 16
5.2.3. Tree-Based Construction . . . . . . . . . . . . . . . 16
5.3. Serial Constructions . . . . . . . . . . . . . . . . . . 17
5.3.1. Serial Construction Based on a KDF on a Block Cipher 19
5.3.2. Serial Construction Based on a KDF on a Hash Function 19
5.4. Using Additional Entropy during Re-keying . . . . . . . . 19
6. Internal Re-keying Mechanisms . . . . . . . . . . . . . . . . 20
6.1. Methods of Key Lifetime Control . . . . . . . . . . . . . 22
6.2. Constructions that Do Not Require a Master Key . . . . . 23
6.2.1. ACPKM Re-keying Mechanisms . . . . . . . . . . . . . 23
6.2.2. CTR-ACPKM Encryption Mode . . . . . . . . . . . . . . 25
6.2.3. GCM-ACPKM Authenticated Encryption Mode . . . . . . . 26
6.3. Constructions that Require a Master Key . . . . . . . . . 29
6.3.1. ACPKM-Master Key Derivation from the Master Key . . . 29
6.3.2. CTR-ACPKM-Master Encryption Mode . . . . . . . . . . 31
6.3.3. GCM-ACPKM-Master Authenticated Encryption Mode . . . 33
6.3.4. CBC-ACPKM-Master Encryption Mode . . . . . . . . . . 37
6.3.5. CFB-ACPKM-Master Encryption Mode . . . . . . . . . . 39
6.3.6. OMAC-ACPKM-Master Authentication Mode . . . . . . . . 40
7. Joint Usage of External and Internal Re-keying . . . . . . . 42
8. Security Considerations . . . . . . . . . . . . . . . . . . . 43
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 43
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 44
10.1. Normative References . . . . . . . . . . . . . . . . . . 44
10.2. Informative References . . . . . . . . . . . . . . . . . 45
Appendix A. Test Examples . . . . . . . . . . . . . . . . . . . 48
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