Merge pull request #291 from ralexstokes/add-ed25519-support

Adds support for verifying ed25519 signatures, for secio

libp2p/crypto/ed25519.py

@@ -0,0 +1,70 @@
+from Crypto.Hash import SHA256
+from nacl.exceptions import BadSignatureError
+from nacl.public import PrivateKey as PrivateKeyImpl
+from nacl.public import PublicKey as PublicKeyImpl
+from nacl.signing import SigningKey, VerifyKey
+import nacl.utils as utils
+
+from libp2p.crypto.keys import KeyPair, KeyType, PrivateKey, PublicKey
+
+
+class Ed25519PublicKey(PublicKey):
+    def __init__(self, impl: PublicKeyImpl) -> None:
+        self.impl = impl
+
+    def to_bytes(self) -> bytes:
+        return bytes(self.impl)
+
+    @classmethod
+    def from_bytes(cls, key_bytes: bytes) -> "Ed25519PublicKey":
+        return cls(PublicKeyImpl(key_bytes))
+
+    def get_type(self) -> KeyType:
+        return KeyType.Ed25519
+
+    def verify(self, data: bytes, signature: bytes) -> bool:
+        verify_key = VerifyKey(self.to_bytes())
+        h = SHA256.new(data)
+        try:
+            verify_key.verify(h, signature)
+        except BadSignatureError:
+            return False
+        return True
+
+
+class Ed25519PrivateKey(PrivateKey):
+    def __init__(self, impl: PrivateKeyImpl) -> None:
+        self.impl = impl
+
+    @classmethod
+    def new(cls, seed: bytes = None) -> "Ed25519PrivateKey":
+        if not seed:
+            seed = utils.random()
+
+        private_key_impl = PrivateKeyImpl.from_seed(seed)
+        return cls(private_key_impl)
+
+    def to_bytes(self) -> bytes:
+        return bytes(self.impl)
+
+    @classmethod
+    def from_bytes(cls, data: bytes) -> "Ed25519PrivateKey":
+        impl = PrivateKeyImpl(data)
+        return cls(impl)
+
+    def get_type(self) -> KeyType:
+        return KeyType.Ed25519
+
+    def sign(self, data: bytes) -> bytes:
+        h = SHA256.new(data)
+        signing_key = SigningKey(self.to_bytes())
+        return signing_key.sign(h)
+
+    def get_public_key(self) -> PublicKey:
+        return Ed25519PublicKey(self.impl.public_key)
+
+
+def create_new_key_pair(seed: bytes = None) -> KeyPair:
+    private_key = Ed25519PrivateKey.new(seed)
+    public_key = private_key.get_public_key()
+    return KeyPair(private_key, public_key)

libp2p/crypto/exceptions.py

@@ -0,0 +1,14 @@
+from libp2p.exceptions import BaseLibp2pError
+
+
+class CryptographyError(BaseLibp2pError):
+    pass
+
+
+class MissingDeserializerError(CryptographyError):
+    """
+    Raise if the requested deserialization routine is missing for
+    some type of cryptographic key.
+    """
+
+    pass

libp2p/crypto/serialization.py

@@ -1,3 +1,5 @@
+from libp2p.crypto.ed25519 import Ed25519PrivateKey, Ed25519PublicKey
+from libp2p.crypto.exceptions import MissingDeserializerError
 from libp2p.crypto.keys import KeyType, PrivateKey, PublicKey
 from libp2p.crypto.rsa import RSAPublicKey
 from libp2p.crypto.secp256k1 import Secp256k1PrivateKey, Secp256k1PublicKey
@@ -5,20 +7,28 @@ from libp2p.crypto.secp256k1 import Secp256k1PrivateKey, Secp256k1PublicKey
 key_type_to_public_key_deserializer = {
     KeyType.Secp256k1.value: Secp256k1PublicKey.from_bytes,
     KeyType.RSA.value: RSAPublicKey.from_bytes,
+    KeyType.Ed25519.value: Ed25519PublicKey.from_bytes,
 }
 
 key_type_to_private_key_deserializer = {
-    KeyType.Secp256k1.value: Secp256k1PrivateKey.from_bytes
+    KeyType.Secp256k1.value: Secp256k1PrivateKey.from_bytes,
+    KeyType.Ed25519.value: Ed25519PrivateKey.from_bytes,
 }
 
 
 def deserialize_public_key(data: bytes) -> PublicKey:
     f = PublicKey.deserialize_from_protobuf(data)
-    deserializer = key_type_to_public_key_deserializer[f.key_type]
+    try:
+        deserializer = key_type_to_public_key_deserializer[f.key_type]
+    except KeyError:
+        raise MissingDeserializerError({"key_type": f.key_type, "key": "public_key"})
     return deserializer(f.data)
 
 
 def deserialize_private_key(data: bytes) -> PrivateKey:
     f = PrivateKey.deserialize_from_protobuf(data)
-    deserializer = key_type_to_private_key_deserializer[f.key_type]
+    try:
+        deserializer = key_type_to_private_key_deserializer[f.key_type]
+    except KeyError:
+        raise MissingDeserializerError({"key_type": f.key_type, "key": "private_key"})
     return deserializer(f.data)

libp2p/crypto/utils.py

@@ -1,17 +0,0 @@
-from .keys import PublicKey
-from .pb import crypto_pb2 as protobuf
-from .rsa import RSAPublicKey
-from .secp256k1 import Secp256k1PublicKey
-
-
-def pubkey_from_protobuf(pubkey_pb: protobuf.PublicKey) -> PublicKey:
-    if pubkey_pb.key_type == protobuf.RSA:
-        return RSAPublicKey.from_bytes(pubkey_pb.data)
-    # TODO: Test against secp256k1 keys
-    elif pubkey_pb.key_type == protobuf.Secp256k1:
-        return Secp256k1PublicKey.from_bytes(pubkey_pb.data)
-    # TODO: Support `Ed25519` and `ECDSA` in the future?
-    else:
-        raise ValueError(
-            f"unsupported key_type={pubkey_pb.key_type}, data={pubkey_pb.data!r}"
-        )

libp2p/security/insecure/transport.py

@@ -2,7 +2,7 @@ from typing import Optional
 
 from libp2p.crypto.keys import PrivateKey, PublicKey
 from libp2p.crypto.pb import crypto_pb2
-from libp2p.crypto.utils import pubkey_from_protobuf
+from libp2p.crypto.serialization import deserialize_public_key
 from libp2p.io.abc import ReadWriteCloser
 from libp2p.network.connection.exceptions import RawConnError
 from libp2p.network.connection.raw_connection_interface import IRawConnection
@@ -75,7 +75,9 @@ class InsecureSession(BaseSession):
 
         # Verify if the given `pubkey` matches the given `peer_id`
         try:
-            received_pubkey = pubkey_from_protobuf(remote_msg.pubkey)
+            received_pubkey = deserialize_public_key(
+                remote_msg.pubkey.SerializeToString()
+            )
         except ValueError:
             raise HandshakeFailure(
                 f"unknown `key_type` of remote_msg.pubkey={remote_msg.pubkey}"

setup.py

@@ -41,6 +41,7 @@ setuptools.setup(
         "protobuf==3.9.0",
         "coincurve>=10.0.0,<11.0.0",
         "fastecdsa==1.7.4",
+        "pynacl==1.3.0",
     ],
     extras_require=extras_require,
     packages=setuptools.find_packages(exclude=["tests", "tests.*"]),

tests/crypto/test_ed25519.py

@@ -0,0 +1,22 @@
+from libp2p.crypto.ed25519 import create_new_key_pair
+from libp2p.crypto.serialization import deserialize_private_key, deserialize_public_key
+
+
+def test_public_key_serialize_deserialize_round_trip():
+    key_pair = create_new_key_pair()
+    public_key = key_pair.public_key
+
+    public_key_bytes = public_key.serialize()
+    another_public_key = deserialize_public_key(public_key_bytes)
+
+    assert public_key == another_public_key
+
+
+def test_private_key_serialize_deserialize_round_trip():
+    key_pair = create_new_key_pair()
+    private_key = key_pair.private_key
+
+    private_key_bytes = private_key.serialize()
+    another_private_key = deserialize_private_key(private_key_bytes)
+
+    assert private_key == another_private_key