H33-74 on Ethereum

Ethereum is one of H33-74's anchor surfaces, not its foundation. The receipt exists before the Ethereum anchor and remains valid if the Ethereum anchor is later supplemented or replaced on another chain. Ethereum provides one independent notarization. H33-74 receipts can carry many.

How H33-74 anchors to Ethereum

Each anchor is a Ethereum transaction that commits to a receipt's cryptographic identity (or to a batched commitment covering many receipts). The anchor lives in Ethereum's canonical ledger and is independently verifiable via any Ethereum block explorer.

Anchor mechanism on Ethereum

H33-74 anchors to Ethereum via EIP-1559 transactions whose calldata contains the receipt's 32-byte commitment (or a Merkle root over a batch). The anchoring transaction is a self-send (no value transfer) with the commitment embedded in calldata so any Ethereum node can index and verify it.

Chain parameters

Chain

Ethereum (chain ID 1)

Finality

Probabilistic finality at 12 blocks (~3 minutes); full finality at 64-95 blocks (~12-15 minutes) under proof-of-stake.

Anchor cost

Variable with network conditions; typically 0.0005-0.005 ETH per batched anchor depending on calldata size and gas price.

Explorer

etherscan.io

What an H33-74 anchor record contains

The 32-byte commitment from the receipt (or a Merkle root if batched).
Sufficient on-chain bytes for a third party to verify the commitment matches the receipt.
A timestamp from the Ethereum block, providing independent proof that the receipt existed by no later than that block.

What it does not contain: sensitive payload data. The receipt's content lives off-chain. The anchor only commits to its existence and identity.

When Ethereum is the right anchor

Ethereum is the right anchor for receipts that need to interoperate with other Ethereum-based attestation infrastructure (EAS, Verax, Sign Protocol) without depending on them, when the operator's ecosystem is already Ethereum-native, and when calldata-based commitment is preferable to opcode-based commitment (OP_RETURN-style). Ethereum's finality is fast and settlement assurance is high.

The portability story

A receipt anchored on Ethereum can also be anchored on Bitcoin, Ethereum, Solana, Polygon zkEVM, Zcash, or any other chain H33-74 supports. The anchors are independent. Adding more anchors does not change the receipt. Removing one anchor (or having one chain become unavailable) does not invalidate the others.

If Ethereum ever becomes inappropriate for an operator's use case (regulatory, performance, security, cost), the operator adds an anchor on a different chain and continues operating. The historical evidence does not have to migrate, because it was never bound to Ethereum.

Verifying a Ethereum anchor

A third-party verifier needs the H33-74 receipt, the Ethereum anchor transaction (or its hash), and the open-source H33 verifier. From those inputs:

The verifier checks the three post-quantum signatures over the receipt (ML-DSA-65, FALCON-512, SLH-DSA-128f).
The verifier checks that the Ethereum anchor transaction commits to the receipt's identity.
The verifier reads the Ethereum block timestamp to establish independent existence-time.

None of those steps depends on H33's infrastructure. The verifier is open-source and the chain is public.

See H33-74 on other chains

The same receipts that anchor to Ethereum can anchor to any of the others.

One Receipt. Multiple Chains. H33-74 Overview