Add abstraction for a cryptographic key

libp2p/crypto/rsa.py

@@ -0,0 +1,54 @@
+from typing import Tuple
+
+import Crypto.PublicKey.RSA as RSA
+from Crypto.PublicKey.RSA import RsaKey
+
+from libp2p.crypto.keys import KeyType, PrivateKey, PublicKey
+
+
+class RSAPublicKey(PublicKey):
+    def __init__(self, impl: RsaKey) -> None:
+        self.impl = impl
+
+    def to_bytes(self) -> bytes:
+        return self.impl.export_key("DER")
+
+    def get_type(self) -> KeyType:
+        return KeyType.RSA
+
+    def verify(self, data: bytes, signature: bytes) -> bool:
+        raise NotImplementedError
+
+
+class RSAPrivateKey(PrivateKey):
+    def __init__(self, impl: RsaKey) -> None:
+        self.impl = impl
+
+    @classmethod
+    def new(cls, bits: int = 2048, e: int = 65537) -> "RSAPrivateKey":
+        private_key_impl = RSA.generate(bits, e=e)
+        return cls(private_key_impl)
+
+    def to_bytes(self) -> bytes:
+        return self.impl.export_key("DER")
+
+    def get_type(self) -> KeyType:
+        return KeyType.RSA
+
+    def sign(self, data: bytes) -> bytes:
+        raise NotImplementedError
+
+    def get_public_key(self) -> PublicKey:
+        return RSAPublicKey(self.impl.publickey())
+
+
+def create_new_key_pair(
+    bits: int = 2048, e: int = 65537
+) -> Tuple[PrivateKey, PublicKey]:
+    """
+    Returns a new RSA keypair with the requested key size (``bits``) and the given public
+    exponent ``e``. Sane defaults are provided for both values.
+    """
+    private_key = RSAPrivateKey.new(bits, e)
+    public_key = private_key.get_public_key()
+    return private_key, public_key