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Overview

RFC 3161 defines a protocol for trusted timestamps from a Time Stamping Authority (TSA). SESHAT integrates with FreeTSA, providing ISO/IEC 18014-2 certified timestamps.

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Why TSA Timestamps?

While blockchain provides timestamps, RFC 3161 adds:
FeatureBlockchainRFC 3161
StandardCustomISO/IEC 18014-2
Legal acceptanceGrowingEstablished
VerificationOn-chainOffline possible
IndependenceCrypto ecosystemTraditional PKI
Belt and suspenders: Use both for maximum legal protection.

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Configuration

ENABLE_TSA=true
TSA_URL=https://freetsa.org/tsr  # Default

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How It Works

1

Hash Prepared

The Merkle root of your bundle is computed.
2

Request Sent

ASN.1 DER-encoded TimeStampReq sent to TSA.
3

Token Received

TSA returns signed TimeStampResp (.tsr file).
4

Stored

TIMESTAMP.tsr included in bundle.

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Verification

Verify with OpenSSL: 
# Download FreeTSA certificate chain
curl -O https://freetsa.org/files/cacert.pem
curl -O https://freetsa.org/files/tsa.crt

# Verify timestamp
openssl ts -verify \
  -in TIMESTAMP.tsr \
  -data PROOF_CHAIN.json \
  -CAfile cacert.pem \
  -untrusted tsa.crt
Expected output: 
Verification: OK

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FreeTSA Details

  • Provider: FreeTSA.org
  • Standard: RFC 3161 / ISO/IEC 18014-2
  • Cost: Free
  • Accuracy: Synchronized to UTC
  • Certificate: Publicly verifiable
FreeTSA timestamps are legally recognized in most jurisdictions that accept electronic timestamps.