Reference projects

The base library owns generic algebra, circuit compilation, transcripts, commitments, sumcheck, and proof machinery. Named projects turn those tools into statements about particular formats or signature schemes.

Project	Proves or packages	Curve / format	Package target
mdoc	Signed mobile-document parsing and selective disclosure	ISO mdoc, CBOR, ECDSA P-256	LongfellowZKMDoc::mdoc
ECDSA	ECDSA signature verification circuits	P-256	LongfellowZKECDSA::ecdsa
BIP340	Schnorr verification circuits and witnesses	secp256k1 / BIP340	LongfellowZKBIP340::bip340

Dependency direction

mdoc ──────> ECDSA ──────> liblongfellow-zk
BIP340 ──────────────────> liblongfellow-zk

The base never includes named-project headers. This keeps application-specific document and signature logic outside the reusable cryptographic boundary. See the library boundary inventory for the enforced ownership rules.

Why these three?

They cover two complementary goals. mdoc is an end-to-end identity application: it parses a deployed document, checks its signature, and supports selective claims. ECDSA and BIP340 are smaller cryptographic building blocks that show how legacy and modern signature verification can live inside a private statement.