Content Identifiers are central to the Codex protocol.
A CID is a self-describing content-addressed identifier. It uses cryptographic hashes to achieve content addressing. It uses several multiformats to achieve flexible self-description, namely:
- multihash to hash content addressed, and
- multicodec to type that addressed content, to form a binary self-contained identifier, and optionally also
- multibase to encode that binary CID as a string.
Concretely:
<cidv1> ::= <CIDv1-multicodec><content-type-multicodec><content-multihash>
Source: https://github.com/multiformats/cid. See also: https://docs.ipfs.tech/concepts/content-addressing/#content-identifiers-cids.