Post-Quantum On-Chain Attestation in 74 Bytes

Post-quantum cryptography has a size problem. The signature algorithms that NIST standardized to resist quantum computers produce signatures that are orders of magnitude larger than their classical counterparts. An Ed25519 signature is 64 bytes. An ML-DSA-65 (Dilithium) signature is 3,309 bytes. A FALCON-512 signature is approximately 690 bytes. An SLH-DSA-SHA2-128f signature is 17,088 bytes. A three-family signature bundle combining all three for defense in depth totals approximately 21,087 bytes. Storing 21KB per attestation on a blockchain is economically absurd and technically impractical. H33-74 solves this problem by distilling the full three-family attestation into exactly 74 bytes.

The distinction between distillation and compression matters. Compression implies that the original data can be reconstructed from the compressed form. H33-74 is not compression. You cannot reconstruct the full 21KB signature bundle from 74 bytes. What H33-74 preserves is the cryptographic guarantee: anyone who holds the 74-byte primitive can verify that the original three-family signature was valid, that the computation it attests to was performed correctly, and that the attestation has not been tampered with. The full signatures exist in Cachee for on-demand verification, but the 74-byte primitive on-chain is sufficient to establish the chain of trust.

The On-Chain Cost Problem

Every byte stored on a blockchain has a cost. On Solana, the current rent-exempt minimum for storing account data is approximately 0.00089 SOL per byte per epoch. On Bitcoin, OP_RETURN data costs transaction fees proportional to the data size. On Ethereum, each byte of calldata costs gas. These costs are designed to prevent spam and ensure that on-chain storage is used for data that needs the immutability and global consensus that blockchains provide.

At 21KB per attestation, a three-family post-quantum signature bundle would cost roughly 100 to 1,000 times more than a classical Ed25519 signature to store on-chain. For a system processing 2,293,766 attestations per second, the on-chain storage cost would be astronomical even if only a fraction of attestations are anchored. The entire premise of on-chain attestation, which is to provide an immutable public record of cryptographic events, becomes economically unviable if each record costs dollars instead of fractions of a cent.

H33-74 reduces the on-chain footprint to 74 bytes. At current Solana rates, anchoring a 74-byte attestation costs less than a thousandth of a cent. This makes it economically feasible to anchor every attestation produced by the pipeline, creating a continuous, publicly verifiable record of every post-quantum-signed computation without the storage cost driving the system economics into the ground.

How Distillation Works

The H33-74 primitive has two components: 32 bytes that live on-chain and 42 bytes that reside in Cachee (H33's high-performance caching layer). The 32 on-chain bytes are a SHA3-256 hash that commits to the full attestation record, including all three post-quantum signatures, the STARK proof, the computation circuit identifier, the timestamp, and the input/output commitments. The 42 Cachee bytes contain a structured index that enables efficient lookup of the full attestation record for on-demand verification.

The 32-byte on-chain hash functions as a cryptographic anchor. Once this hash is committed to a blockchain, it becomes immutable and globally verifiable. Anyone can take a full attestation record, compute its SHA3-256 hash, and compare it to the on-chain value. If they match, the attestation record is authentic and has not been modified since it was anchored. If they do not match, the record has been tampered with. This is the same commitment scheme used by Merkle trees, certificate transparency logs, and other systems that need to verify data integrity against a trusted root.

The 42-byte Cachee component contains a structured lookup key that includes a tenant identifier, a batch sequence number, and a verification nonce. This allows the full attestation record to be retrieved from Cachee in sub-microsecond time for complete verification. The full record includes all three post-quantum signatures (ML-DSA, FALCON, SLH-DSA), the STARK proof, and the metadata needed for independent verification. The Cachee component is not on-chain because it does not need to be; the on-chain hash already commits to the full record, and Cachee provides the storage layer for the complete data.

Three Families, One Primitive

The three post-quantum signature families in H33-74 rest on three independent hardness assumptions. ML-DSA (formerly Dilithium) is based on the Module Learning With Errors (MLWE) problem over lattices. FALCON is based on the NTRU lattice problem with a different mathematical structure than MLWE. SLH-DSA (formerly SPHINCS+) is based on the security of stateless hash functions, specifically SHA3-256 in H33's configuration, with no lattice structure at all.

This diversity is the core security property of H33-74. If a future breakthrough breaks MLWE lattices (compromising ML-DSA), the FALCON and SLH-DSA signatures remain valid. If NTRU lattices fall (compromising FALCON), ML-DSA and SLH-DSA remain valid. If hash functions are somehow weakened (compromising SLH-DSA), the two lattice-based families remain valid. An attacker must simultaneously break three different mathematical problems to forge an H33-74 attestation. No known or theoretical quantum algorithm achieves this.

The distillation process combines the verification outputs of all three families into the single SHA3-256 hash. The hash input includes the three signatures, the three verification results, the signed message, and structural metadata that binds the components together. Because SHA3-256 is itself a post-quantum-secure hash function, the binding between the components is quantum-resistant as well. The entire chain from individual signatures through combination to on-chain anchoring is designed to resist quantum attack at every step.

Bitcoin Anchoring

Bitcoin anchoring uses the OP_RETURN opcode to embed 32 bytes of attestation data in a Bitcoin transaction. OP_RETURN creates a provably unspendable output that miners include in the blockchain without adding to the UTXO set. The 32-byte H33-74 hash becomes part of Bitcoin's immutable ledger, inheriting Bitcoin's proof-of-work security guarantees.

Bitcoin's block time of approximately 10 minutes means attestations are anchored in batches rather than individually. H33 aggregates attestation hashes into a Merkle tree and anchors the Merkle root to Bitcoin, allowing millions of individual attestations to share a single Bitcoin transaction. This batched Merkle approach is covered by H33's patent-pending claims and provides logarithmic proof sizes for verifying any individual attestation against the Bitcoin anchor.

The cost of a single Bitcoin OP_RETURN transaction is determined by the current fee market, but the Merkle batching means this cost is amortized across all attestations in the batch. Even at high Bitcoin fee levels, the per-attestation anchoring cost remains negligible because a single transaction can commit to millions of attestations.

Solana Anchoring

Solana anchoring takes advantage of Solana's high throughput and low transaction costs to anchor attestations more frequently than Bitcoin allows. Solana's 400-millisecond block time means attestations can be anchored within seconds rather than waiting for a Bitcoin block. The 32-byte hash is stored as account data on Solana, with the remaining 42 bytes serving as the Cachee lookup key.

Solana's finality guarantees are different from Bitcoin's proof-of-work finality. Solana uses a proof-of-stake consensus mechanism with tower BFT (Byzantine Fault Tolerance), which provides faster finality but under different trust assumptions. For applications that need the strongest possible immutability guarantees, Bitcoin anchoring provides proof-of-work security. For applications that need fast confirmation and lower cost, Solana anchoring provides a practical alternative. H33 supports both, and the same H33-74 primitive works on either chain.

Verification Flow

Verifying an H33-74 attestation is a multi-step process that any third party can perform independently. First, retrieve the 32-byte on-chain hash from the blockchain. Second, use the 42-byte Cachee lookup key to retrieve the full attestation record from Cachee. Third, compute the SHA3-256 hash of the full attestation record and compare it to the on-chain value. If they match, the record is authentic. Fourth, verify each of the three post-quantum signatures in the full record against the signed message. Fifth, verify the STARK proof to confirm computation correctness.

Steps three through five can be performed by anyone without any special keys or permissions. The verification is entirely based on public information: the on-chain hash, the full attestation record from Cachee, and the public verification keys for the three signature families. This transparency is a design requirement. H33-74 attestations are meant to be verified by auditors, regulators, counterparties, and automated compliance systems, none of whom should need to trust H33 or the original computation provider.

Comparison to Raw On-Chain Signatures

Without H33-74, post-quantum on-chain attestation would require storing the full signature bundle on-chain. At 21,087 bytes for a three-family bundle, this creates severe practical problems. On Solana, rent-exempt storage for 21KB of account data costs approximately 0.15 SOL per attestation. At millions of attestations per day, this becomes a significant operational cost. On Bitcoin, embedding 21KB in an OP_RETURN is not possible because OP_RETURN is limited to 80 bytes. You would need to use inscription mechanisms that are even more expensive.

H33-74 reduces the on-chain footprint by a factor of approximately 285 times (21,087 bytes to 74 bytes). This is not a theoretical savings. It is the difference between a system that can economically anchor every attestation and a system that can only anchor a small fraction. At H33's production throughput of 2,293,766 operations per second, storing full signature bundles would generate approximately 48 gigabytes of on-chain data per second. The 74-byte distillation reduces this to approximately 170 megabytes per second of on-chain data, which remains large but is manageable with batched Merkle anchoring.

Patent Protection

The H33-74 distillation process and the batched Merkle response attestation mechanism are covered by patent-pending claims, specifically Claims 124-125 in H33's substrate patent filing. These claims cover the method of distilling multi-family post-quantum signatures into a fixed-width primitive and the method of batching attestations into Merkle trees for efficient on-chain anchoring. This patent protection ensures that the specific distillation technique remains proprietary to H33 while the verification process remains transparent and publicly executable.

The Bottom Line

Post-quantum cryptography produces large signatures. Blockchains charge for storage. These two facts are in direct tension, and without a solution, post-quantum on-chain attestation is economically unviable. H33-74 resolves this tension by distilling three post-quantum signature families into a 74-byte primitive that preserves the full cryptographic guarantees at a fraction of the cost. Thirty-two bytes on-chain, forty-two bytes in Cachee, and the full security of ML-DSA, FALCON, and SLH-DSA available for on-demand verification. This is not a compromise. It is the architecture that makes post-quantum attestation practical at production scale.