RFC 4122 - A Universally Unique IDentifier (UUID) URN Namespace

Published: July 2005
Status: Standards Track
Authors: P. Leach (Microsoft), M. Mealling (Refactored Networks, LLC), R. Salz (DataPower Technology, Inc.)

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Abstract

This specification defines a Uniform Resource Name namespace for UUIDs (Universally Unique IDentifier), also known as GUIDs (Globally Unique IDentifier). A UUID is 128 bits long, and can guarantee uniqueness across space and time. UUIDs were originally used in the Apollo Network Computing System and later in the Open Software Foundation's (OSF) Distributed Computing Environment (DCE), and then in Microsoft Windows platforms.

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Table of Contents

• 1. Introduction
• 2. Motivation
• 3. Namespace Registration Template
• 4. Specification
  • 4.1. Format
  • 4.2. Algorithms for Creating a Time-Based UUID
  • 4.3. Algorithm for Creating a Name-Based UUID
  • 4.4. Algorithms for Creating a UUID from Truly Random or Pseudo-Random Numbers
  • 4.5. Node IDs that Do Not Identify the Host
• 5. Community Considerations
• 6. Security Considerations
• 7. Acknowledgments
• 8. Normative References

Appendices

• Appendix A. Sample Implementation
• Appendix B. Sample Output of utest
• Appendix C. Some Name Space IDs

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Related Resources

• Official Text: RFC 4122
• Official Page: RFC 4122 DataTracker
• Errata: RFC Editor Errata

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