1 files changed, 101 insertions, 0 deletions
diff --git a/frozen_deps/Cryptodome/Protocol/DH.py b/frozen_deps/Cryptodome/Protocol/DH.py
new file mode 100644
index 0000000..bb174f0
--- /dev/null
+++ b/frozen_deps/Cryptodome/Protocol/DH.py
@@ -0,0 +1,101 @@
+from Cryptodome.Util.number import long_to_bytes
+from Cryptodome.PublicKey.ECC import EccKey
+
+
+def _compute_ecdh(key_priv, key_pub):
+ # See Section 5.7.1.2 in NIST SP 800-56Ar3
+ pointP = key_pub.pointQ * key_priv.d
+ if pointP.is_point_at_infinity():
+ raise ValueError("Invalid ECDH point")
+ z = long_to_bytes(pointP.x, pointP.size_in_bytes())
+ return z
+
+
+def key_agreement(**kwargs):
+ """Perform a Diffie-Hellman key agreement.
+
+ Keywords:
+ kdf (callable):
+ A key derivation function that accepts ``bytes`` as input and returns
+ ``bytes``.
+ static_priv (EccKey):
+ The local static private key. Optional.
+ static_pub (EccKey):
+ The static public key that belongs to the peer. Optional.
+ eph_priv (EccKey):
+ The local ephemeral private key, generated for this session. Optional.
+ eph_pub (EccKey):
+ The ephemeral public key, received from the peer for this session. Optional.
+
+ At least two keys must be passed, of which one is a private key and one
+ a public key.
+
+ Returns (bytes):
+ The derived secret key material.
+ """
+
+ static_priv = kwargs.get('static_priv', None)
+ static_pub = kwargs.get('static_pub', None)
+ eph_priv = kwargs.get('eph_priv', None)
+ eph_pub = kwargs.get('eph_pub', None)
+ kdf = kwargs.get('kdf', None)
+
+ if kdf is None:
+ raise ValueError("'kdf' is mandatory")
+
+ count_priv = 0
+ count_pub = 0
+ curve = None
+
+ def check_curve(curve, key, name, private):
+ if not isinstance(key, EccKey):
+ raise TypeError("'%s' must be an ECC key" % name)
+ if private and not key.has_private():
+ raise TypeError("'%s' must be a private ECC key" % name)
+ if curve is None:
+ curve = key.curve
+ elif curve != key.curve:
+ raise TypeError("'%s' is defined on an incompatible curve" % name)
+ return curve
+
+ if static_priv is not None:
+ curve = check_curve(curve, static_priv, 'static_priv', True)
+ count_priv += 1
+
+ if static_pub is not None:
+ curve = check_curve(curve, static_pub, 'static_pub', False)
+ count_pub += 1
+
+ if eph_priv is not None:
+ curve = check_curve(curve, eph_priv, 'eph_priv', True)
+ count_priv += 1
+
+ if eph_pub is not None:
+ curve = check_curve(curve, eph_pub, 'eph_pub', False)
+ count_pub += 1
+
+ if (count_priv + count_pub) < 2 or count_priv == 0 or count_pub == 0:
+ raise ValueError("Too few keys for the ECDH key agreement")
+
+ Zs = b''
+ Ze = b''
+
+ if static_priv and static_pub:
+ # C(*, 2s)
+ Zs = _compute_ecdh(static_priv, static_pub)
+
+ if eph_priv and eph_pub:
+ # C(2e, 0s) or C(2e, 2s)
+ if bool(static_priv) != bool(static_pub):
+ raise ValueError("DH mode C(2e, 1s) is not supported")
+ Ze = _compute_ecdh(eph_priv, eph_pub)
+ elif eph_priv and static_pub:
+ # C(1e, 2s) or C(1e, 1s)
+ Ze = _compute_ecdh(eph_priv, static_pub)
+ elif eph_pub and static_priv:
+ # C(1e, 2s) or C(1e, 1s)
+ Ze = _compute_ecdh(static_priv, eph_pub)
+
+ Z = Ze + Zs
+
+ return kdf(Z)