RFC 7049 - Concise Binary Object Representation (CBOR)

RFC 7049 - Concise Binary Object Representation (CBOR)

Status: Standards Track
Published: October 2013
Authors: C. Bormann (Universitaet Bremen TZI), P. Hoffman (VPN Consortium)

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.

Contents

• 1. Introduction
  • 1.1. Objectives
  • 1.2. Terminology
• 2. Specification of the CBOR Encoding
  • 2.1. Major Types
  • 2.2. Indefinite Lengths for Some Major Types
    • 2.2.1. Indefinite-Length Arrays and Maps
    • 2.2.2. Indefinite-Length Byte Strings and Text Strings
  • 2.3. Floating-Point Numbers and Values with No Content
  • 2.4. Optional Tagging of Items
    • 2.4.1. Date and Time
    • 2.4.2. Bignums
    • 2.4.3. Decimal Fractions and Bigfloats
    • 2.4.4. Content Hints
    • 2.4.5. Self-Describe CBOR
• 3. Creating CBOR-Based Protocols
  • 3.1. CBOR in Streaming Applications
  • 3.2. Generic Encoders and Decoders
  • 3.3. Syntax Errors
  • 3.4. Other Decoding Errors
  • 3.5. Handling Unknown Simple Values and Tags
  • 3.6. Numbers
  • 3.7. Specifying Keys for Maps
  • 3.8. Undefined Values
  • 3.9. Canonical CBOR
  • 3.10. Strict Mode
• 4. Converting Data between CBOR and JSON
  • 4.1. Converting from CBOR to JSON
  • 4.2. Converting from JSON to CBOR
• 5. Future Evolution of CBOR
  • 5.1. Extension Points
  • 5.2. Curating the Additional Information Space
• 6. Diagnostic Notation
  • 6.1. Encoding Indicators
• 7. IANA Considerations
  • 7.1. Simple Values Registry
  • 7.2. Tags Registry
  • 7.3. Media Type ("MIME Type")
  • 7.4. CoAP Content-Format
  • 7.5. The +cbor Structured Syntax Suffix Registration
• 8. Security Considerations
• 9. Acknowledgements
• 10. References
  • 10.1. Normative References
  • 10.2. Informative References
• Appendix A. Examples
• Appendix B. Jump Table
• Appendix C. Pseudocode
• Appendix D. Half-Precision
• Appendix E. Comparison of Other Binary Formats to CBOR's Design Objectives

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