add missing file

Author: jschlyter

src/cryptojwt/jws/eddsa.py

@@ -0,0 +1,50 @@
+import sys
+
+from cryptography.exceptions import InvalidSignature
+from cryptography.hazmat.primitives.asymmetric import ed448
+from cryptography.hazmat.primitives.asymmetric import ed25519
+
+from ..exception import BadSignature
+from ..exception import Unsupported
+from . import Signer
+
+
+class EDDSASigner(Signer):
+    def sign(self, msg, key):
+        """
+        Create a signature over a message as defined in RFC7515 using an
+        Octet Key Pair key
+
+        :param msg: The message
+        :param key: An Ed25519PrivateKey or Ed448PrivateKey instance
+        :return:
+        """
+
+        if not isinstance(key, (ed25519.Ed25519PrivateKey, ed448.Ed448PrivateKey)):
+            raise TypeError(
+                "The private key must be an instance of Ed25519PrivateKey or Ed448PrivateKey"
+            )
+
+        return key.sign(msg)
+
+    def verify(self, msg, sig, key):
+        """
+        Verify a message signature
+
+        :param msg: The message
+        :param sig: A signature
+        :param key: A Ed25519PublicKey or Ed448PublicKey to use for the verification.
+        :raises: BadSignature if the signature can't be verified.
+        :return: True
+        """
+        if not isinstance(key, (ed25519.Ed25519PublicKey, ed448.Ed448PublicKey)):
+            raise TypeError(
+                "The public key must be an instance of Ed25519PublicKey or Ed448PublicKey"
+            )
+
+        try:
+            key.verify(sig, msg)
+        except InvalidSignature as err:
+            raise BadSignature(err)
+        else:
+            return True