curve25519

Bindings for x25519.

Hint

curve25519 has been designed so all points on the curve have the desired security properties. This makes picking a point (i.e. generating a private key) using secrets.token_bytes(32) (or os.urandom(32)) easy, safe and recommended.

pyhacl.diffie_hellman.curve25519.ecdh(private_key: bytes, public_key: bytes) → bytes

Given our 32-bytes private key, and the 32-bytes public key of a peer, compute and return a third 32-bytes key. The peer is also capable of computing this same secret key given our public key and their private key.

Parameters:

• private_key – Our private key, as a 32 bytes point.

• public_key – Their public key, as a 32 bytes point.

Raises:

ValueError – When any key has an incorrect length.

Uses Hacl_Curve25519_51_ecdh.

pyhacl.diffie_hellman.curve25519.scalarmult(private_key: bytes, public_key: bytes) → bytes

Compute the scalar multiple of a point. It returns the resulting point encoded in 32 bytes.

Raises:

ValueError – When any key has an incorrect length.

Uses Hacl_Curve25519_51_scalarmult.

pyhacl.diffie_hellman.curve25519.secret_to_public(private_key: bytes) → bytes

Calculate a public point from a private key.

Raises:

ValueError – When the key has an incorrect length.

Uses Hacl_Curve25519_51_secret_to_public.