RFC 8949 - Concise Binary Object Representation (CBOR)

Abstract

The Concise Binary Object Representation (CBOR) is a data format whose design goals include the possibility of extremely small code size, fairly small message size, and extensibility without the need for version negotiation. These design goals make it different from earlier binary serializations such as ASN.1 and MessagePack.

This document obsoletes RFC 7049, providing editorial improvements, new details, and errata fixes while keeping full compatibility with the interchange format of RFC 7049. It does not create a new version of the format.

Status: Standards Track
Published: December 2020
Obsoletes: RFC 7049

Contents

• 1. Introduction
  • 1.1. Objectives
  • 1.2. Terminology
• 2. CBOR Data Models
  • 2.1. Extended Generic Data Models
  • 2.2. Specific Data Models
• 3. Specification of the CBOR Encoding
  • 3.1. Major Types
  • 3.2. Indefinite Lengths for Some Major Types
  • 3.3. Floating-Point Numbers and Values with No Content
  • 3.4. Tagging of Items
• 4. Serialization Considerations
• 5. Creating CBOR-Based Protocols
• 6. Converting Data between CBOR and JSON
• 7. Future Evolution of CBOR
• 8. Diagnostic Notation
• 9. IANA Considerations
• 10. Security Considerations
• 11. References
• Appendix A. Examples of Encoded CBOR Data Items
• Appendix B. Jump Table for Initial Byte
• Appendix C. Pseudocode
• Appendix D. Half-Precision
• Appendix E. Comparison of Other Binary Formats
• Appendix F. Well-Formedness Errors and Examples
• Appendix G. Changes from RFC 7049