Add abstraction for a cryptographic key

libp2p/crypto/keys.py

@@ -0,0 +1,75 @@
+from abc import ABC, abstractmethod
+from enum import Enum, unique
+
+from .pb import crypto_pb2 as protobuf
+
+
+@unique
+class KeyType(Enum):
+    RSA = 0
+    Ed25519 = 1
+    Secp256k1 = 2
+    ECDSA = 3
+
+
+class Key:
+    """
+    A ``Key`` represents a cryptographic key.
+    """
+
+    @abstractmethod
+    def to_bytes(self) -> bytes:
+        """
+        Returns the byte representation of this key.
+        """
+        ...
+
+    @abstractmethod
+    def get_type(self) -> KeyType:
+        """
+        Returns the ``KeyType`` for ``self``.
+        """
+        ...
+
+
+class PublicKey(ABC, Key):
+    """
+    A ``PublicKey`` represents a cryptographic public key.
+    """
+
+    @abstractmethod
+    def verify(self, data: bytes, signature: bytes) -> bool:
+        """
+        Verify that ``signature`` is the cryptographic signature of the hash of ``data``.
+        """
+        ...
+
+    def serialize_to_protobuf(self) -> protobuf.PublicKey:
+        _type = self.get_type()
+        data = self.to_bytes()
+        protobuf_key = protobuf.PublicKey()
+        protobuf_key.key_type = _type.value
+        protobuf_key.data = data
+        return protobuf_key
+
+
+class PrivateKey(ABC, Key):
+    """
+    A ``PrivateKey`` represents a cryptographic private key.
+    """
+
+    @abstractmethod
+    def sign(self, data: bytes) -> bytes:
+        ...
+
+    @abstractmethod
+    def get_public_key(self) -> PublicKey:
+        ...
+
+    def serialize_to_protobuf(self) -> protobuf.PrivateKey:
+        _type = self.get_type()
+        data = self.to_bytes()
+        protobuf_key = protobuf.PrivateKey()
+        protobuf_key.key_type = _type.value
+        protobuf_key.data = data
+        return protobuf_key