serai/crypto/ciphersuite/README.md
2023-03-20 20:10:00 -04:00

1.8 KiB

Ciphersuite

Ciphersuites for elliptic curves premised on ff/group.

This library, except for the not recommended Ed448 ciphersuite, was audited by Cypher Stack in March 2023, culminating in commit 669d2dbffc1dafb82a09d9419ea182667115df06. Any subsequent changes have not undergone auditing.

Secp256k1/P-256

Secp256k1 and P-256 are offered via k256 and p256, two libraries maintained by RustCrypto.

Their hash_to_F is the IETF's hash to curve, yet applied to their scalar field.

Ed25519/Ristretto

Ed25519/Ristretto are offered via dalek-ff-group, an ff/group wrapper around curve25519-dalek.

Their hash_to_F is the wide reduction of SHA2-512, as used in RFC-8032. This is also compliant with the draft RFC-RISTRETTO. The domain-separation tag is naively prefixed to the message.

Ed448

Ed448 is offered via minimal-ed448, an explicitly not recommended, unaudited, incomplete Ed448 implementation, limited to its prime-order subgroup.

Its hash_to_F is the wide reduction of SHAKE256, with a 114-byte output, as used in RFC-8032. The domain-separation tag is naively prefixed to the message.