Anchoring is a cryptographic method for establishing existence-at-or-before-T of a byte sequence.
It is formally defined by the verification function:
Anchoring does not establish authorship, ownership, originality, identity, intent, legal validity, or truthfulness.
A compliant anchoring proof must remain verifiable independently of the issuing entity. Verification must not require issuer-controlled infrastructure.
Ledger systems must provide public verifiability and resistance to unilateral timestamp rewriting.
Output semantics are strictly limited to three defined states. No additional, partial, or qualified outputs are permitted.
Hash functions must be publicly specified, collision-resistant, and widely reviewed. Time T is defined as the earliest consensus-confirmed inclusion point in the ledger. Anchoring does not establish exact creation time.
Anchoring does not permit retroactive modification of proof validity once ledger inclusion is finalized. Proofs should be stored in durable, non-proprietary formats.
An implementation claiming compliance shall state the IEC version, hash function, ledger type, and any deviations from default proof structure.
The specification is normative. Implementations are not.