Lib25519 is a microlibrary for the X25519 encryption system and the Ed25519 signature system, both of which use the Curve25519 elliptic curve.

lib25519 has a very simple stateless API based on the SUPERCOP API, with wire-format inputs and outputs, providing functions that directly match the central cryptographic operations in X25519 and Ed25519:

lib25519.x25519.keypair(pk, sk): X25519 key generation lib25519.x25519.dh(k, pk, sk): shared-secret generation lib25519.ed25519.keypair(pk, sk): Ed25519 key generation lib25519.ed25519.sign(sm, &smlen, m, mlen, sk): signing lib25519.ed25519.open(m, &mlen, sm, smlen, pk): verification + message recovery