RFC 3161 Timestamps

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.

Why TSA Timestamps?

While blockchain provides timestamps, RFC 3161 adds:

Feature	Blockchain	RFC 3161
Standard	Custom	ISO/IEC 18014-2
Legal acceptance	Growing	Established
Verification	On-chain	Offline possible
Independence	Crypto ecosystem	Traditional PKI

Belt and suspenders: Use both for maximum legal protection.

Configuration

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

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.

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

FreeTSA Details

• Provider: FreeTSA.org
• Standard: RFC 3161 / ISO/IEC 18014-2
• Cost: Free
• Accuracy: Synchronized to UTC
• Certificate: Publicly verifiable

Note

FreeTSA timestamps are legally recognized in most jurisdictions that accept electronic timestamps.