Related · tier-1 reading. For what a portable artifact actually is, see Portable Artifact.
Sign Protocol pioneered on-chain attestation with a unified schema across chains. H33-74 makes the evidence chain-portable instead of multi-chain.
Sign Protocol provides a chain-agnostic-in-marketing-sense attestation primitive. Schemas, attestations, and revocations live on chain, with cross-chain registries letting attestations be referenced from multiple EVM chains. Sign's design center is on-chain composability of attestations across chains.
Both projects acknowledge that single-chain attestation is too narrow. Both produce structured attestations rather than just timestamps. Both have schema concepts for attestation types. Both support multiple chains.
Sign Protocol is great when on-chain composability of attestations across EVM chains is the value being delivered, when attestation consumers are smart contracts, and when the operator is comfortable with pre-quantum signatures for the audit horizon.
H33-74 is great when attestation consumers are auditors and regulators outside the EVM ecosystem. When the receipt needs to survive any single chain's deprecation or compromise. When post-quantum survivability matters. When the audit horizon extends past chain-ecosystem lifetimes.
Scope of this comparison. This page compares how each system locates and protects an attestation, not overall project quality, ecosystem size, or roadmap. Sign Protocol's on-chain composability and cross-chain registry design are genuine strengths for smart-contract consumers; they are not deficiencies.
Evidence source. Sign Protocol attributes are drawn from its public documentation at docs.sign.global (schema, attestation, and cross-chain registry model). H33-74 attributes are drawn from the receipt schema v1.0, the attestation receipt spec, and published benchmarks. Version and date: comparison prepared against Sign Protocol public docs as of July 2026; H33-74 receipt schema v1.0.
What is not being claimed. This is not a claim that H33-74 is superior for every use case, nor that Sign Protocol is insecure. Sign uses ECDSA, which is appropriate for its consumer model today; H33-74's three-family post-quantum signing (ML-DSA / FIPS 204 and SLH-DSA / FIPS 205 finalized; FALCON / FN-DSA is FIPS 206 draft) targets a longer audit horizon. Neither is "unbreakable"; both rest on assumptions stated in their specs.
Canonical flagship. H33-74 produces and anchors the portable 74-byte post-quantum evidence primitive this comparison references; this page reinforces that primitive and does not redefine it.
Verification path. Any H33-74 receipt is checked by an independent offline verifier that recomputes the 32-byte commitment and confirms the anchor with H33 out of the loop — see how verification works.
Chain portability separates evidence from the infrastructure that produced it — a difference in design center, not a verdict on either project.
Chain Portability What Gets Preserved