RFC 8439 - ChaCha20 and Poly1305 for IETF Protocols

Status: Informational
Published: June 2018
Obsoletes: RFC 7539

Abstract

This document defines the ChaCha20 stream cipher as well as the use of the Poly1305 authenticator, both as stand-alone algorithms and as a "combined mode", or Authenticated Encryption with Associated Data (AEAD) algorithm.

RFC 7539, the predecessor of this document, was meant to serve as a stable reference and an implementation guide. It was a product of the Crypto Forum Research Group (CFRG). This document merges the errata filed against RFC 7539 and adds a little text to the Security Considerations section.

Contents

• 1. Introduction
  • 1.1 Conventions Used in This Document
• 2. The Algorithms
  • 2.1 The ChaCha Quarter Round
  • 2.2 A Quarter Round on the ChaCha State
  • 2.3 The ChaCha20 Block Function
  • 2.4 The ChaCha20 Encryption Algorithm
  • 2.5 The Poly1305 Algorithm
  • 2.6 Generating the Poly1305 Key Using ChaCha20
  • 2.7 A Pseudorandom Function for Crypto Suites
  • 2.8 AEAD Construction
• 3. Implementation Advice
• 4. Security Considerations
• 5. IANA Considerations
• 6. References
  • 6.1 Normative References
  • 6.2 Informative References
• Appendix A. Additional Test Vectors
• Appendix B. Performance Measurements
• Acknowledgements
• Authors' Addresses

Document Information

• RFC: 8439
• Category: Informational
• ISSN: 2070-1721
• Authors:
  • Y. Nir (Dell EMC)
  • A. Langley (Google, Inc.)
• Source: Internet Research Task Force (IRTF)
• Obsoletes: RFC 7539

Copyright Notice

Copyright (c) 2018 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.