~/talk

Timestamping with OpenTimestamps

Talkat SFSCON 2025 · 2025-11-07..11-08· [bitcoin, web-platform]
links:none on file
slides:none on file

OpenTimestamps uses Bitcoin to create trustless timestamps by hashing many file hashes into a Merkle tree and writing only the root onchain, making proofs compact and cheap; experiments also port to Ethereum. A Guardian Project app captures image metadata (JSON with PNG signature), timestamps it with OpenTimestamps, and produces verifiable proofs that have been used as evidence; precision is coarse at ~3‑hour precision. A quick clone of a competing service is built in hours and functions.

AI-written summary · about

  1. 0:00What is timestamping
  2. 2:14Why use the blockchain
  3. 5:11What is OpenTimestamps
  4. 8:30OpenTimestamps in practice
  5. 10:15Proof mode for media
  6. 12:32Legal validity and precision
  7. 15:33Q&A
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