ed25519 support (#4114)

* ed25519 support

* review feedback

1 files changed, 80 insertions, 0 deletions

diff --git a/src/cryptography/hazmat/primitives/asymmetric/ed25519.py b/src/cryptography/hazmat/primitives/asymmetric/ed25519.py
new file mode 100644
index 00000000..96be9c58
--- /dev/null
+++ b/src/cryptography/hazmat/primitives/asymmetric/ed25519.py
@@ -0,0 +1,80 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+
+from __future__ import absolute_import, division, print_function
+
+import abc
+
+import six
+
+from cryptography.exceptions import UnsupportedAlgorithm, _Reasons
+
+
+@six.add_metaclass(abc.ABCMeta)
+class Ed25519PublicKey(object):
+    @classmethod
+    def from_public_bytes(cls, data):
+        from cryptography.hazmat.backends.openssl.backend import backend
+        if not backend.ed25519_supported():
+            raise UnsupportedAlgorithm(
+                "ed25519 is not supported by this version of OpenSSL.",
+                _Reasons.UNSUPPORTED_PUBLIC_KEY_ALGORITHM
+            )
+
+        return backend.ed25519_load_public_bytes(data)
+
+    @abc.abstractmethod
+    def public_bytes(self, encoding, format):
+        """
+        The serialized bytes of the public key.
+        """
+
+    @abc.abstractmethod
+    def verify(self, signature, data):
+        """
+        Verify the signature.
+        """
+
+
+@six.add_metaclass(abc.ABCMeta)
+class Ed25519PrivateKey(object):
+    @classmethod
+    def generate(cls):
+        from cryptography.hazmat.backends.openssl.backend import backend
+        if not backend.ed25519_supported():
+            raise UnsupportedAlgorithm(
+                "ed25519 is not supported by this version of OpenSSL.",
+                _Reasons.UNSUPPORTED_PUBLIC_KEY_ALGORITHM
+            )
+
+        return backend.ed25519_generate_key()
+
+    @classmethod
+    def from_private_bytes(cls, data):
+        from cryptography.hazmat.backends.openssl.backend import backend
+        if not backend.ed25519_supported():
+            raise UnsupportedAlgorithm(
+                "ed25519 is not supported by this version of OpenSSL.",
+                _Reasons.UNSUPPORTED_PUBLIC_KEY_ALGORITHM
+            )
+
+        return backend.ed25519_load_private_bytes(data)
+
+    @abc.abstractmethod
+    def public_key(self):
+        """
+        The Ed25519PublicKey derived from the private key.
+        """
+
+    @abc.abstractmethod
+    def private_bytes(self, encoding, format, encryption_algorithm):
+        """
+        The serialized bytes of the private key.
+        """
+
+    @abc.abstractmethod
+    def sign(self, data):
+        """
+        Signs the data.
+        """