diff --git a/libp2p/crypto/keys.py b/libp2p/crypto/keys.py
index b0dec3d..31caca0 100644
--- a/libp2p/crypto/keys.py
+++ b/libp2p/crypto/keys.py
@@ -45,18 +45,29 @@ class PublicKey(Key):
         """
         ...
 
-    def serialize_to_protobuf(self) -> protobuf.PublicKey:
+    def _serialize_to_protobuf(self) -> protobuf.PublicKey:
+        """
+        Return the protobuf representation of this ``Key``.
+        """
         key_type = self.get_type().value
         data = self.to_bytes()
         protobuf_key = protobuf.PublicKey(key_type=key_type, data=data)
         return protobuf_key
 
+    def serialize(self) -> bytes:
+        """
+        Return the canonical serialization of this ``Key``.
+        """
+        return self._serialize_to_protobuf().SerializeToString()
+
 
 class PrivateKey(Key):
     """
     A ``PrivateKey`` represents a cryptographic private key.
     """
 
+    protobuf_constructor = protobuf.PrivateKey
+
     @abstractmethod
     def sign(self, data: bytes) -> bytes:
         ...
@@ -65,12 +76,21 @@ class PrivateKey(Key):
     def get_public_key(self) -> PublicKey:
         ...
 
-    def serialize_to_protobuf(self) -> protobuf.PrivateKey:
+    def _serialize_to_protobuf(self) -> protobuf.PrivateKey:
+        """
+        Return the protobuf representation of this ``Key``.
+        """
         key_type = self.get_type().value
         data = self.to_bytes()
         protobuf_key = protobuf.PrivateKey(key_type=key_type, data=data)
         return protobuf_key
 
+    def serialize(self) -> bytes:
+        """
+        Return the canonical serialization of this ``Key``.
+        """
+        return self._serialize_to_protobuf().SerializeToString()
+
 
 @dataclass(frozen=True)
 class KeyPair:
diff --git a/libp2p/peer/id.py b/libp2p/peer/id.py
index 26029b6..303f519 100644
--- a/libp2p/peer/id.py
+++ b/libp2p/peer/id.py
@@ -7,13 +7,6 @@ import multihash
 from libp2p.crypto.keys import PublicKey
 
 
-def _serialize_public_key(key: PublicKey) -> bytes:
-    """
-    Serializes ``key`` in the way expected to form valid peer ids.
-    """
-    return key.serialize_to_protobuf().SerializeToString()
-
-
 class ID:
     _bytes: bytes
     _xor_id: int = None
@@ -62,7 +55,7 @@ class ID:
 
     @classmethod
     def from_pubkey(cls, key: PublicKey) -> "ID":
-        serialized_key = _serialize_public_key(key)
+        serialized_key = key.serialize()
         algo = multihash.Func.sha2_256
         mh_digest = multihash.digest(serialized_key, algo)
         return cls(mh_digest.encode())
diff --git a/tests/peer/test_peerid.py b/tests/peer/test_peerid.py
index 30b74c1..ea244ce 100644
--- a/tests/peer/test_peerid.py
+++ b/tests/peer/test_peerid.py
@@ -92,7 +92,7 @@ def test_id_from_public_key():
     key_pair = create_new_key_pair()
     public_key = key_pair.public_key
 
-    key_bin = public_key.serialize_to_protobuf().SerializeToString()
+    key_bin = public_key.serialize()
     algo = multihash.Func.sha2_256
     mh_digest = multihash.digest(key_bin, algo)
     expected = ID(mh_digest.encode())