Implemented proxies to pyca X25519

RNS/Cryptography/Proxies.py

@@ -0,0 +1,43 @@
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey, Ed25519PublicKey
+from cryptography.hazmat.primitives.asymmetric.x25519 import X25519PrivateKey, X25519PublicKey
+
+class X25519PrivateKeyProxy:
+    def __init__(self, real):
+        self.real = real
+
+    @classmethod
+    def generate(cls):
+        return cls(X25519PrivateKey.generate())
+
+    @classmethod
+    def from_private_bytes(cls, data):
+        return cls(X25519PrivateKey.from_private_bytes(data))
+
+    def private_bytes(self):
+        return self.real.private_bytes(
+            encoding=serialization.Encoding.Raw,
+            format=serialization.PrivateFormat.Raw,
+            encryption_algorithm=serialization.NoEncryption(),
+        )
+
+    def public_key(self):
+        return X25519PublicKeyProxy(self.real.public_key())
+
+    def exchange(self, peer_public_key):
+        return self.real.exchange(peer_public_key.real)
+
+
+class X25519PublicKeyProxy:
+    def __init__(self, real):
+        self.real = real
+
+    @classmethod
+    def from_public_bytes(cls, data):
+        return cls(X25519PublicKey.from_public_bytes(data))
+
+    def public_bytes(self):
+        return self.real.public_bytes(
+            encoding=serialization.Encoding.Raw,
+            format=serialization.PublicFormat.Raw
+        )