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Trusted Timestamps (RFC 3161): How to Anchor a Hash Chain So No One Can Rewrite the Past

A hash chain proves a record was not modified after it was written. It does not prove when it was written, and it does nothing against someone who controls the server and can re-sign the whole chain.

  • Trusted Timestamps (RFC 3161) solve hash chain limitations
  • Time Stamp Authority (TSA) vouches for hash existence at specific time
  • Two anchoring strategies: per-record stamping vs periodic chain-head stamping

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