def encode_public(self, public_key: ec.EllipticCurvePublicKey,
f_pub: _FragList) -> None:
"""Write ECDSA public key"""
point = public_key.public_bytes(Encoding.X962,
PublicFormat.UncompressedPoint)
f_pub.put_sshstr(self.ssh_curve_name)
f_pub.put_sshstr(point)
def calculate_secret(self, slot: SLOT,
peer_public_key: ec.EllipticCurvePublicKey) -> bytes:
key_type = KEY_TYPE.from_public_key(peer_public_key)
if key_type.algorithm != ALGORITHM.EC:
raise ValueError("Unsupported key type")
data = peer_public_key.public_bytes(Encoding.X962,
PublicFormat.UncompressedPoint)
return self._use_private_key(slot, key_type, data, True)
def get_public_key_bytes_compressed(
public_key: ec.EllipticCurvePublicKey) -> bytes:
""" Returns the bytes from a cryptography ec.EllipticCurvePublicKey in a compressed format
:param public_key: Public key object
:type public_key: ec.EllipticCurvePublicKey
:rtype: bytes
"""
return public_key.public_bytes(Encoding.X962, PublicFormat.CompressedPoint)
def derive_ecdh(self, public_key: ec.EllipticCurvePublicKey) -> bytes:
"""Perform an ECDH key exchange as specified in SP 800-56A.
:param public_key: The public key to use for the key exchange.
:return: The resulting shared key.
"""
point = public_key.public_bytes(Encoding.X962,
PublicFormat.UncompressedPoint)
msg = struct.pack("!H", self.id) + point
return self.session.send_secure_cmd(COMMAND.DERIVE_ECDH, msg)
def generate_public_pem(public_key: ec.EllipticCurvePublicKey) -> bytes:
"""
Generates a Privacy Enhanced Mail (pem) from the public key
This may be send to the other party
:param public_key: ec.EllipticCurvePublicKey
:return: Privacy Enhanced Mail message
:rtype: bytes
"""
__assure_public_key(public_key)
pem = public_key.public_bytes(
encoding=serialization.Encoding.PEM,
format=serialization.PublicFormat.SubjectPublicKeyInfo)
return pem
def get_public_key_bytes_compressed(
public_key: ec.EllipticCurvePublicKey) -> bytes:
"""Return the bytes of a pubkey in the compressed format."""
return public_key.public_bytes(Encoding.X962, PublicFormat.CompressedPoint)