H33-74 vs OpenTimestamps

OpenTimestamps (OTS) is the de-facto open standard for blockchain timestamping. It has anchored hundreds of millions of timestamps to Bitcoin since 2016. It is reliable, well-understood, free to use, and the architectural pattern (batched Merkle root anchoring) is exactly the pattern H33-74 inherits.

So what does H33-74 do that OpenTimestamps does not?

What they share

• Both produce small cryptographic receipts that can be created without coordinating with the chain in real time.
• Both use batched Merkle-root anchoring to bring per-receipt cost to near-zero at scale.
• Both keep the receipt content off-chain; the chain only holds a commitment.
• Both allow third-party verification without coordinating with the original operator.

What H33-74 adds

Post-quantum signatures

OTS receipts are SHA-256 hashes anchored to Bitcoin. They are timestamping receipts, not signed receipts. Their integrity rests on Bitcoin's SHA-256 and ECDSA, both of which are vulnerable to known quantum algorithms when sufficiently capable quantum computers exist. H33-74 receipts carry three independent post-quantum signatures (ML-DSA-65, FALCON-512, SLH-DSA-128f) on the receipt content itself, so the receipt's integrity is post-quantum even if the chain it was anchored to later becomes compromised.

Chain portability

OTS is structurally bound to Bitcoin. The receipt format, the batching mechanism, and the verification pipeline assume Bitcoin as the notarization chain. H33-74 receipts can be anchored to Bitcoin, Ethereum, Solana, Polygon zkEVM, Zcash, or any other chain that can hold a 32-byte commitment, and the same receipt can carry multiple chain anchors simultaneously.

Computation semantics

OTS attests to the existence of arbitrary file contents at a point in time. H33-74 attests to the result of a bounded computation (an AI decision, a compliance determination, a governance vote, a transfer authorization) with structured semantics that the verifier can interpret. The receipt does not just say "this file existed" — it says "this specific computation produced this specific result under this specific policy at this specific time."

Operational reconstruction

OTS proves a single timestamp. H33-74 receipts are designed to compose into operational histories. A collection of H33-74 receipts for a fund's five-year operation lets an auditor reconstruct what happened, in what order, under what authority. OTS does not have receipt-to-receipt linkage semantics.

Direct comparison

When OpenTimestamps is the right choice

OpenTimestamps is great when you only need Bitcoin timestamping of file existence, when single-chain anchoring is sufficient, and when post-quantum survivability is not a near-term concern. It is mature, free, and battle-tested for document notarization.

When H33-74 is the right choice

H33-74 is great when the attested fact is more than file existence — a decision, an authorization, a compliance determination, an AI output. When the receipt needs to survive Bitcoin's eventual deprecation or compromise. When multi-chain notarization is operationally valuable. When post-quantum signatures are required for long audit horizons. When batched anchoring is needed for high-volume systems.

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