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RFC · Data formatsStandard explained

RFC 4122: UUIDs: Unique identifiers without central allocation

Summary

RFC 4122 standardises the UUID structure and several generation methods for distributed unique identifiers. RFC 4122 was superseded by RFC 9562. Decentralised identifiers decouple data creation from central numbering authorities.

Ideas

  • 128 bits offer a very large identifier space.
  • Versions encode different generation methods.
  • The text representation uses five hexadecimal groups.

Insights

  • Uniqueness replaces neither authenticity nor access control.

Remarks

  • RFC 4122 has the status “Proposed Standard”; current errata and successor documents should also be checked.

Recommendations

  • Use RFC 9562 as the current successor.
  • Choose the UUID version according to privacy, sorting and collision risk.

References

Read the RFC at the RFC Editor

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