ed25519 support (#4114)

* ed25519 support

* review feedback

11 files changed, 782 insertions, 0 deletions

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 7c3f3bfe..8bca9b2b 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -20,6 +20,8 @@ Changelog
 * **BACKWARDS INCOMPATIBLE**: Removed ``cryptography.x509.Certificate.serial``,
   which had been deprecated for nearly 3 years. Use
   :attr:`~cryptography.x509.Certificate.serial_number` instead.
+* Added support for :doc:`/hazmat/primitives/asymmetric/ed25519` when using
+  OpenSSL 1.1.1.
 * Add support for easily mapping an object identifier to its elliptic curve
   class via
   :func:`~cryptography.hazmat.primitives.asymmetric.ec.get_curve_for_oid`.
diff --git a/docs/hazmat/primitives/asymmetric/ed25519.rst b/docs/hazmat/primitives/asymmetric/ed25519.rst
new file mode 100644
index 00000000..8893fbbd
--- /dev/null
+++ b/docs/hazmat/primitives/asymmetric/ed25519.rst
@@ -0,0 +1,159 @@
+.. hazmat::
+
+Ed25519 signing
+===============
+
+.. currentmodule:: cryptography.hazmat.primitives.asymmetric.ed25519
+
+
+Ed25519 is an elliptic curve signing algorithm using `EdDSA`_ and
+`Curve25519`_. If you do not have legacy interoperability concerns then you
+should strongly consider using this signature algorithm.
+
+
+Signing & Verification
+~~~~~~~~~~~~~~~~~~~~~~
+
+.. doctest::
+
+    >>> from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
+    >>> private_key = Ed25519PrivateKey.generate()
+    >>> signature = private_key.sign(b"my authenticated message")
+    >>> public_key = private_key.public_key()
+    >>> # Raises InvalidSignature if verification fails
+    >>> public_key.verify(signature, b"my authenticated message")
+
+Key interfaces
+~~~~~~~~~~~~~~
+
+.. class:: Ed25519PrivateKey
+
+    .. versionadded:: 2.6
+
+    .. classmethod:: generate()
+
+        Generate an Ed25519 private key.
+
+        :returns: :class:`Ed25519PrivateKey`
+
+    .. classmethod:: from_private_bytes(data)
+
+        :param data: 32 byte private key.
+        :type data: :term:`bytes-like`
+
+        :returns: :class:`Ed25519PrivateKey`
+
+        .. doctest::
+
+            >>> from cryptography.hazmat.primitives import serialization
+            >>> from cryptography.hazmat.primitives.asymmetric import ed25519
+            >>> private_key = ed25519.Ed25519PrivateKey.generate()
+            >>> private_bytes = private_key.private_bytes(
+            ...     encoding=serialization.Encoding.Raw,
+            ...     format=serialization.PrivateFormat.Raw,
+            ...     encryption_algorithm=serialization.NoEncryption()
+            ... )
+            >>> loaded_private_key = ed25519.Ed25519PrivateKey.from_private_bytes(private_bytes)
+
+
+    .. method:: public_key()
+
+        :returns: :class:`Ed25519PublicKey`
+
+    .. method:: sign(data)
+
+        :param bytes data: The data to sign.
+
+        :returns bytes: The 64 byte signature.
+
+    .. method:: private_bytes(encoding, format, encryption_algorithm)
+
+        Allows serialization of the key to bytes. Encoding (
+        :attr:`~cryptography.hazmat.primitives.serialization.Encoding.PEM`,
+        :attr:`~cryptography.hazmat.primitives.serialization.Encoding.DER`, or
+        :attr:`~cryptography.hazmat.primitives.serialization.Encoding.Raw`) and
+        format (
+        :attr:`~cryptography.hazmat.primitives.serialization.PrivateFormat.PKCS8`
+        or
+        :attr:`~cryptography.hazmat.primitives.serialization.PrivateFormat.Raw`
+        ) are chosen to define the exact serialization.
+
+        :param encoding: A value from the
+            :class:`~cryptography.hazmat.primitives.serialization.Encoding` enum.
+
+        :param format: A value from the
+            :class:`~cryptography.hazmat.primitives.serialization.PrivateFormat`
+            enum. If the ``encoding`` is
+            :attr:`~cryptography.hazmat.primitives.serialization.Encoding.Raw`
+            then ``format`` must be
+            :attr:`~cryptography.hazmat.primitives.serialization.PrivateFormat.Raw`
+            , otherwise it must be
+            :attr:`~cryptography.hazmat.primitives.serialization.PrivateFormat.PKCS8`.
+
+        :param encryption_algorithm: An instance of an object conforming to the
+            :class:`~cryptography.hazmat.primitives.serialization.KeySerializationEncryption`
+            interface.
+
+        :return bytes: Serialized key.
+
+.. class:: Ed25519PublicKey
+
+    .. versionadded:: 2.6
+
+    .. classmethod:: from_public_bytes(data)
+
+        :param bytes data: 32 byte public key.
+
+        :returns: :class:`Ed25519PublicKey`
+
+        .. doctest::
+
+            >>> from cryptography.hazmat.primitives import serialization
+            >>> from cryptography.hazmat.primitives.asymmetric import ed25519
+            >>> private_key = ed25519.Ed25519PrivateKey.generate()
+            >>> public_key = private_key.public_key()
+            >>> public_bytes = public_key.public_bytes(
+            ...     encoding=serialization.Encoding.Raw,
+            ...     format=serialization.PublicFormat.Raw
+            ... )
+            >>> loaded_public_key = ed25519.Ed25519PublicKey.from_public_bytes(public_bytes)
+
+    .. method:: public_bytes(encoding, format)
+
+        Allows serialization of the key to bytes. Encoding (
+        :attr:`~cryptography.hazmat.primitives.serialization.Encoding.PEM`,
+        :attr:`~cryptography.hazmat.primitives.serialization.Encoding.DER`, or
+        :attr:`~cryptography.hazmat.primitives.serialization.Encoding.Raw`) and
+        format (
+        :attr:`~cryptography.hazmat.primitives.serialization.PublicFormat.SubjectPublicKeyInfo`
+        or
+        :attr:`~cryptography.hazmat.primitives.serialization.PublicFormat.Raw`
+        ) are chosen to define the exact serialization.
+
+        :param encoding: A value from the
+            :class:`~cryptography.hazmat.primitives.serialization.Encoding` enum.
+
+        :param format: A value from the
+            :class:`~cryptography.hazmat.primitives.serialization.PublicFormat`
+            enum. If the ``encoding`` is
+            :attr:`~cryptography.hazmat.primitives.serialization.Encoding.Raw`
+            then ``format`` must be
+            :attr:`~cryptography.hazmat.primitives.serialization.PublicFormat.Raw`
+            , otherwise it must be
+            :attr:`~cryptography.hazmat.primitives.serialization.PublicFormat.SubjectPublicKeyInfo`.
+
+        :returns bytes: The public key bytes.
+
+    .. method:: verify(signature, data)
+
+        :param bytes signature: The signature to verify.
+
+        :param bytes data: The data to verify.
+
+        :raises cryptography.exceptions.InvalidSignature: Raised when the
+            signature cannot be verified.
+
+
+
+.. _`EdDSA`: https://en.wikipedia.org/wiki/EdDSA
+.. _`Curve25519`: https://en.wikipedia.org/wiki/Curve25519
diff --git a/docs/hazmat/primitives/asymmetric/index.rst b/docs/hazmat/primitives/asymmetric/index.rst
index 1561c59f..5e5bdb9a 100644
--- a/docs/hazmat/primitives/asymmetric/index.rst
+++ b/docs/hazmat/primitives/asymmetric/index.rst
@@ -23,6 +23,7 @@ private key is able to decrypt it.
 .. toctree::
     :maxdepth: 1
 
+    ed25519
     x25519
     x448
     ec
diff --git a/docs/spelling_wordlist.txt b/docs/spelling_wordlist.txt
index 7e08f124..c9b4777e 100644
--- a/docs/spelling_wordlist.txt
+++ b/docs/spelling_wordlist.txt
@@ -53,6 +53,7 @@ hostname
 idna
 indistinguishability
 initialisms
+interoperability
 interoperable
 introspectability
 invariants
diff --git a/src/_cffi_src/openssl/cryptography.py b/src/_cffi_src/openssl/cryptography.py
index 23ce87cf..4124dcb8 100644
--- a/src/_cffi_src/openssl/cryptography.py
+++ b/src/_cffi_src/openssl/cryptography.py
@@ -62,6 +62,8 @@ INCLUDES = """
     (OPENSSL_VERSION_NUMBER < 0x101000af || CRYPTOGRAPHY_IS_LIBRESSL)
 #define CRYPTOGRAPHY_OPENSSL_LESS_THAN_111 \
     (OPENSSL_VERSION_NUMBER < 0x10101000 || CRYPTOGRAPHY_IS_LIBRESSL)
+#define CRYPTOGRAPHY_OPENSSL_LESS_THAN_111B \
+    (OPENSSL_VERSION_NUMBER < 0x10101020 || CRYPTOGRAPHY_IS_LIBRESSL)
 """
 
 TYPES = """
@@ -72,6 +74,7 @@ static const int CRYPTOGRAPHY_OPENSSL_110F_OR_GREATER;
 static const int CRYPTOGRAPHY_OPENSSL_LESS_THAN_102I;
 static const int CRYPTOGRAPHY_OPENSSL_LESS_THAN_102;
 static const int CRYPTOGRAPHY_OPENSSL_LESS_THAN_111;
+static const int CRYPTOGRAPHY_OPENSSL_LESS_THAN_111B;
 
 static const int CRYPTOGRAPHY_IS_LIBRESSL;
 
diff --git a/src/cryptography/hazmat/backends/openssl/backend.py b/src/cryptography/hazmat/backends/openssl/backend.py
index e2a5fd78..61f597a3 100644
--- a/src/cryptography/hazmat/backends/openssl/backend.py
+++ b/src/cryptography/hazmat/backends/openssl/backend.py
@@ -37,6 +37,9 @@ from cryptography.hazmat.backends.openssl.dsa import (
 from cryptography.hazmat.backends.openssl.ec import (
     _EllipticCurvePrivateKey, _EllipticCurvePublicKey
 )
+from cryptography.hazmat.backends.openssl.ed25519 import (
+    _ED25519_KEY_SIZE, _Ed25519PrivateKey, _Ed25519PublicKey
+)
 from cryptography.hazmat.backends.openssl.encode_asn1 import (
     _CRL_ENTRY_EXTENSION_ENCODE_HANDLERS,
     _CRL_EXTENSION_ENCODE_HANDLERS, _EXTENSION_ENCODE_HANDLERS,
@@ -511,6 +514,9 @@ class Backend(object):
             self.openssl_assert(dh_cdata != self._ffi.NULL)
             dh_cdata = self._ffi.gc(dh_cdata, self._lib.DH_free)
             return _DHPrivateKey(self, dh_cdata, evp_pkey)
+        elif key_type == getattr(self._lib, "EVP_PKEY_ED25519", None):
+            # EVP_PKEY_ED25519 is not present in OpenSSL < 1.1.1
+            return _Ed25519PrivateKey(self, evp_pkey)
         elif key_type == getattr(self._lib, "EVP_PKEY_X448", None):
             # EVP_PKEY_X448 is not present in OpenSSL < 1.1.1
             return _X448PrivateKey(self, evp_pkey)
@@ -548,6 +554,9 @@ class Backend(object):
             self.openssl_assert(dh_cdata != self._ffi.NULL)
             dh_cdata = self._ffi.gc(dh_cdata, self._lib.DH_free)
             return _DHPublicKey(self, dh_cdata, evp_pkey)
+        elif key_type == getattr(self._lib, "EVP_PKEY_ED25519", None):
+            # EVP_PKEY_ED25519 is not present in OpenSSL < 1.1.1
+            return _Ed25519PublicKey(self, evp_pkey)
         elif key_type == getattr(self._lib, "EVP_PKEY_X448", None):
             # EVP_PKEY_X448 is not present in OpenSSL < 1.1.1
             return _X448PublicKey(self, evp_pkey)
@@ -2188,6 +2197,41 @@ class Backend(object):
     def x448_supported(self):
         return not self._lib.CRYPTOGRAPHY_OPENSSL_LESS_THAN_111
 
+    def ed25519_supported(self):
+        return not self._lib.CRYPTOGRAPHY_OPENSSL_LESS_THAN_111B
+
+    def ed25519_load_public_bytes(self, data):
+        utils._check_bytes("data", data)
+
+        if len(data) != _ED25519_KEY_SIZE:
+            raise ValueError("An Ed25519 public key is 32 bytes long")
+
+        evp_pkey = self._lib.EVP_PKEY_new_raw_public_key(
+            self._lib.NID_ED25519, self._ffi.NULL, data, len(data)
+        )
+        self.openssl_assert(evp_pkey != self._ffi.NULL)
+        evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free)
+
+        return _Ed25519PublicKey(self, evp_pkey)
+
+    def ed25519_load_private_bytes(self, data):
+        if len(data) != _ED25519_KEY_SIZE:
+            raise ValueError("An Ed25519 private key is 32 bytes long")
+
+        utils._check_byteslike("data", data)
+        data_ptr = self._ffi.from_buffer(data)
+        evp_pkey = self._lib.EVP_PKEY_new_raw_private_key(
+            self._lib.NID_ED25519, self._ffi.NULL, data_ptr, len(data)
+        )
+        self.openssl_assert(evp_pkey != self._ffi.NULL)
+        evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free)
+
+        return _Ed25519PrivateKey(self, evp_pkey)
+
+    def ed25519_generate_key(self):
+        evp_pkey = self._evp_pkey_keygen_gc(self._lib.NID_ED25519)
+        return _Ed25519PrivateKey(self, evp_pkey)
+
     def derive_scrypt(self, key_material, salt, length, n, r, p):
         buf = self._ffi.new("unsigned char[]", length)
         key_material_ptr = self._ffi.from_buffer(key_material)
diff --git a/src/cryptography/hazmat/backends/openssl/ed25519.py b/src/cryptography/hazmat/backends/openssl/ed25519.py
new file mode 100644
index 00000000..15c1b1ec
--- /dev/null
+++ b/src/cryptography/hazmat/backends/openssl/ed25519.py
@@ -0,0 +1,154 @@
+# 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
+
+from cryptography import exceptions, utils
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.primitives.asymmetric.ed25519 import (
+    Ed25519PrivateKey, Ed25519PublicKey
+)
+
+_ED25519_KEY_SIZE = 32
+_ED25519_SIG_SIZE = 64
+
+
+@utils.register_interface(Ed25519PublicKey)
+class _Ed25519PublicKey(object):
+    def __init__(self, backend, evp_pkey):
+        self._backend = backend
+        self._evp_pkey = evp_pkey
+
+    def public_bytes(self, encoding, format):
+        if (
+            encoding is serialization.Encoding.Raw or
+            format is serialization.PublicFormat.Raw
+        ):
+            if (
+                encoding is not serialization.Encoding.Raw or
+                format is not serialization.PublicFormat.Raw
+            ):
+                raise ValueError(
+                    "When using Raw both encoding and format must be Raw"
+                )
+
+            return self._raw_public_bytes()
+
+        if (
+            encoding in serialization._PEM_DER and
+            format is not serialization.PublicFormat.SubjectPublicKeyInfo
+        ):
+            raise ValueError(
+                "format must be SubjectPublicKeyInfo when encoding is PEM or "
+                "DER"
+            )
+
+        return self._backend._public_key_bytes(
+            encoding, format, self, self._evp_pkey, None
+        )
+
+    def _raw_public_bytes(self):
+        buf = self._backend._ffi.new("unsigned char []", _ED25519_KEY_SIZE)
+        buflen = self._backend._ffi.new("size_t *", _ED25519_KEY_SIZE)
+        res = self._backend._lib.EVP_PKEY_get_raw_public_key(
+            self._evp_pkey, buf, buflen
+        )
+        self._backend.openssl_assert(res == 1)
+        self._backend.openssl_assert(buflen[0] == _ED25519_KEY_SIZE)
+        return self._backend._ffi.buffer(buf, _ED25519_KEY_SIZE)[:]
+
+    def verify(self, signature, data):
+        evp_md_ctx = self._backend._lib.Cryptography_EVP_MD_CTX_new()
+        self._backend.openssl_assert(evp_md_ctx != self._backend._ffi.NULL)
+        evp_md_ctx = self._backend._ffi.gc(
+            evp_md_ctx, self._backend._lib.Cryptography_EVP_MD_CTX_free
+        )
+        res = self._backend._lib.EVP_DigestVerifyInit(
+            evp_md_ctx, self._backend._ffi.NULL, self._backend._ffi.NULL,
+            self._backend._ffi.NULL, self._evp_pkey
+        )
+        self._backend.openssl_assert(res == 1)
+        res = self._backend._lib.EVP_DigestVerify(
+            evp_md_ctx, signature, len(signature), data, len(data)
+        )
+        if res != 1:
+            self._backend._consume_errors()
+            raise exceptions.InvalidSignature
+
+
+@utils.register_interface(Ed25519PrivateKey)
+class _Ed25519PrivateKey(object):
+    def __init__(self, backend, evp_pkey):
+        self._backend = backend
+        self._evp_pkey = evp_pkey
+
+    def public_key(self):
+        buf = self._backend._ffi.new("unsigned char []", _ED25519_KEY_SIZE)
+        buflen = self._backend._ffi.new("size_t *", _ED25519_KEY_SIZE)
+        res = self._backend._lib.EVP_PKEY_get_raw_public_key(
+            self._evp_pkey, buf, buflen
+        )
+        self._backend.openssl_assert(res == 1)
+        self._backend.openssl_assert(buflen[0] == _ED25519_KEY_SIZE)
+        public_bytes = self._backend._ffi.buffer(buf)[:]
+        return self._backend.ed25519_load_public_bytes(public_bytes)
+
+    def sign(self, data):
+        evp_md_ctx = self._backend._lib.Cryptography_EVP_MD_CTX_new()
+        self._backend.openssl_assert(evp_md_ctx != self._backend._ffi.NULL)
+        evp_md_ctx = self._backend._ffi.gc(
+            evp_md_ctx, self._backend._lib.Cryptography_EVP_MD_CTX_free
+        )
+        res = self._backend._lib.EVP_DigestSignInit(
+            evp_md_ctx, self._backend._ffi.NULL, self._backend._ffi.NULL,
+            self._backend._ffi.NULL, self._evp_pkey
+        )
+        self._backend.openssl_assert(res == 1)
+        buf = self._backend._ffi.new("unsigned char[]", _ED25519_SIG_SIZE)
+        buflen = self._backend._ffi.new("size_t *", len(buf))
+        res = self._backend._lib.EVP_DigestSign(
+            evp_md_ctx, buf, buflen, data, len(data)
+        )
+        self._backend.openssl_assert(res == 1)
+        self._backend.openssl_assert(buflen[0] == _ED25519_SIG_SIZE)
+        return self._backend._ffi.buffer(buf, buflen[0])[:]
+
+    def private_bytes(self, encoding, format, encryption_algorithm):
+        if (
+            encoding is serialization.Encoding.Raw or
+            format is serialization.PublicFormat.Raw
+        ):
+            if (
+                format is not serialization.PrivateFormat.Raw or
+                encoding is not serialization.Encoding.Raw or not
+                isinstance(encryption_algorithm, serialization.NoEncryption)
+            ):
+                raise ValueError(
+                    "When using Raw both encoding and format must be Raw "
+                    "and encryption_algorithm must be NoEncryption"
+                )
+
+            return self._raw_private_bytes()
+
+        if (
+            encoding in serialization._PEM_DER and
+            format is not serialization.PrivateFormat.PKCS8
+        ):
+            raise ValueError(
+                "format must be PKCS8 when encoding is PEM or DER"
+            )
+
+        return self._backend._private_key_bytes(
+            encoding, format, encryption_algorithm, self._evp_pkey, None
+        )
+
+    def _raw_private_bytes(self):
+        buf = self._backend._ffi.new("unsigned char []", _ED25519_KEY_SIZE)
+        buflen = self._backend._ffi.new("size_t *", _ED25519_KEY_SIZE)
+        res = self._backend._lib.EVP_PKEY_get_raw_private_key(
+            self._evp_pkey, buf, buflen
+        )
+        self._backend.openssl_assert(res == 1)
+        self._backend.openssl_assert(buflen[0] == _ED25519_KEY_SIZE)
+        return self._backend._ffi.buffer(buf, _ED25519_KEY_SIZE)[:]
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.
+        """
diff --git a/tests/hazmat/primitives/test_ed25519.py b/tests/hazmat/primitives/test_ed25519.py
new file mode 100644
index 00000000..8a2d3b07
--- /dev/null
+++ b/tests/hazmat/primitives/test_ed25519.py
@@ -0,0 +1,229 @@
+# 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 binascii
+import os
+
+import pytest
+
+from cryptography.exceptions import InvalidSignature, _Reasons
+from cryptography.hazmat.backends.interfaces import DHBackend
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.primitives.asymmetric.ed25519 import (
+    Ed25519PrivateKey, Ed25519PublicKey
+)
+
+from ...utils import (
+    load_vectors_from_file, raises_unsupported_algorithm
+)
+
+
+def load_ed25519_vectors(vector_data):
+    """
+    djb's ed25519 vectors are structured as a colon delimited array:
+        0: secret key (32 bytes) + public key (32 bytes)
+        1: public key (32 bytes)
+        2: message (0+ bytes)
+        3: signature + message (64+ bytes)
+    """
+    data = []
+    for line in vector_data:
+        secret_key, public_key, message, signature, _ = line.split(':')
+        secret_key = secret_key[0:64]
+        signature = signature[0:128]
+        data.append({
+            "secret_key": secret_key,
+            "public_key": public_key,
+            "message": message,
+            "signature": signature
+        })
+    return data
+
+
+@pytest.mark.supported(
+    only_if=lambda backend: not backend.ed25519_supported(),
+    skip_message="Requires OpenSSL without Ed25519 support"
+)
+@pytest.mark.requires_backend_interface(interface=DHBackend)
+def test_ed25519_unsupported(backend):
+    with raises_unsupported_algorithm(
+        _Reasons.UNSUPPORTED_PUBLIC_KEY_ALGORITHM
+    ):
+        Ed25519PublicKey.from_public_bytes(b"0" * 32)
+
+    with raises_unsupported_algorithm(
+        _Reasons.UNSUPPORTED_PUBLIC_KEY_ALGORITHM
+    ):
+        Ed25519PrivateKey.from_private_bytes(b"0" * 32)
+
+    with raises_unsupported_algorithm(
+        _Reasons.UNSUPPORTED_PUBLIC_KEY_ALGORITHM
+    ):
+        Ed25519PrivateKey.generate()
+
+
+@pytest.mark.supported(
+    only_if=lambda backend: backend.ed25519_supported(),
+    skip_message="Requires OpenSSL with Ed25519 support"
+)
+@pytest.mark.requires_backend_interface(interface=DHBackend)
+class TestEd25519Signing(object):
+    @pytest.mark.parametrize(
+        "vector",
+        load_vectors_from_file(
+            os.path.join("asymmetric", "Ed25519", "sign.input"),
+            load_ed25519_vectors
+        )
+    )
+    def test_sign_verify_input(self, vector, backend):
+        sk = binascii.unhexlify(vector["secret_key"])
+        pk = binascii.unhexlify(vector["public_key"])
+        message = binascii.unhexlify(vector["message"])
+        signature = binascii.unhexlify(vector["signature"])
+        private_key = Ed25519PrivateKey.from_private_bytes(sk)
+        computed_sig = private_key.sign(message)
+        assert computed_sig == signature
+        public_key = private_key.public_key()
+        assert public_key.public_bytes(
+            serialization.Encoding.Raw, serialization.PublicFormat.Raw
+        ) == pk
+        public_key.verify(signature, message)
+
+    def test_invalid_signature(self, backend):
+        key = Ed25519PrivateKey.generate()
+        signature = key.sign(b"test data")
+        with pytest.raises(InvalidSignature):
+            key.public_key().verify(signature, b"wrong data")
+
+        with pytest.raises(InvalidSignature):
+            key.public_key().verify(b"0" * 64, b"test data")
+
+    def test_generate(self, backend):
+        key = Ed25519PrivateKey.generate()
+        assert key
+        assert key.public_key()
+
+    def test_load_public_bytes(self, backend):
+        public_key = Ed25519PrivateKey.generate().public_key()
+        public_bytes = public_key.public_bytes(
+            serialization.Encoding.Raw, serialization.PublicFormat.Raw
+        )
+        public_key2 = Ed25519PublicKey.from_public_bytes(public_bytes)
+        assert public_bytes == public_key2.public_bytes(
+            serialization.Encoding.Raw, serialization.PublicFormat.Raw
+        )
+
+    def test_invalid_type_public_bytes(self, backend):
+        with pytest.raises(TypeError):
+            Ed25519PublicKey.from_public_bytes(object())
+
+    def test_invalid_type_private_bytes(self, backend):
+        with pytest.raises(TypeError):
+            Ed25519PrivateKey.from_private_bytes(object())
+
+    def test_invalid_length_from_public_bytes(self, backend):
+        with pytest.raises(ValueError):
+            Ed25519PublicKey.from_public_bytes(b"a" * 31)
+        with pytest.raises(ValueError):
+            Ed25519PublicKey.from_public_bytes(b"a" * 33)
+
+    def test_invalid_length_from_private_bytes(self, backend):
+        with pytest.raises(ValueError):
+            Ed25519PrivateKey.from_private_bytes(b"a" * 31)
+        with pytest.raises(ValueError):
+            Ed25519PrivateKey.from_private_bytes(b"a" * 33)
+
+    def test_invalid_private_bytes(self, backend):
+        key = Ed25519PrivateKey.generate()
+        with pytest.raises(ValueError):
+            key.private_bytes(
+                serialization.Encoding.Raw,
+                serialization.PrivateFormat.Raw,
+                None
+            )
+
+        with pytest.raises(ValueError):
+            key.private_bytes(
+                serialization.Encoding.Raw,
+                serialization.PrivateFormat.PKCS8,
+                None
+            )
+
+        with pytest.raises(ValueError):
+            key.private_bytes(
+                serialization.Encoding.PEM,
+                serialization.PrivateFormat.Raw,
+                serialization.NoEncryption()
+            )
+
+    def test_invalid_public_bytes(self, backend):
+        key = Ed25519PrivateKey.generate().public_key()
+        with pytest.raises(ValueError):
+            key.public_bytes(
+                serialization.Encoding.Raw,
+                serialization.PublicFormat.SubjectPublicKeyInfo
+            )
+
+        with pytest.raises(ValueError):
+            key.public_bytes(
+                serialization.Encoding.PEM,
+                serialization.PublicFormat.PKCS1
+            )
+
+        with pytest.raises(ValueError):
+            key.public_bytes(
+                serialization.Encoding.PEM,
+                serialization.PublicFormat.Raw
+            )
+
+    @pytest.mark.parametrize(
+        ("encoding", "fmt", "encryption", "passwd", "load_func"),
+        [
+            (
+                serialization.Encoding.PEM,
+                serialization.PrivateFormat.PKCS8,
+                serialization.BestAvailableEncryption(b"password"),
+                b"password",
+                serialization.load_pem_private_key
+            ),
+            (
+                serialization.Encoding.DER,
+                serialization.PrivateFormat.PKCS8,
+                serialization.BestAvailableEncryption(b"password"),
+                b"password",
+                serialization.load_der_private_key
+            ),
+            (
+                serialization.Encoding.PEM,
+                serialization.PrivateFormat.PKCS8,
+                serialization.NoEncryption(),
+                None,
+                serialization.load_pem_private_key
+            ),
+            (
+                serialization.Encoding.DER,
+                serialization.PrivateFormat.PKCS8,
+                serialization.NoEncryption(),
+                None,
+                serialization.load_der_private_key
+            ),
+        ]
+    )
+    def test_round_trip_private_serialization(self, encoding, fmt, encryption,
+                                              passwd, load_func, backend):
+        key = Ed25519PrivateKey.generate()
+        serialized = key.private_bytes(encoding, fmt, encryption)
+        loaded_key = load_func(serialized, passwd, backend)
+        assert isinstance(loaded_key, Ed25519PrivateKey)
+
+    def test_buffer_protocol(self, backend):
+        private_bytes = os.urandom(32)
+        key = Ed25519PrivateKey.from_private_bytes(bytearray(private_bytes))
+        assert key.private_bytes(
+            serialization.Encoding.Raw,
+            serialization.PrivateFormat.Raw,
+            serialization.NoEncryption()
+        ) == private_bytes
diff --git a/tests/hazmat/primitives/test_serialization.py b/tests/hazmat/primitives/test_serialization.py
index 5dd72489..52074bf9 100644
--- a/tests/hazmat/primitives/test_serialization.py
+++ b/tests/hazmat/primitives/test_serialization.py
@@ -1285,6 +1285,70 @@ class TestKeySerializationEncryptionTypes(object):
 
 
 @pytest.mark.supported(
+    only_if=lambda backend: backend.ed25519_supported(),
+    skip_message="Requires OpenSSL with Ed25519 support"
+)
+class TestEd25519Serialization(object):
+    def test_load_der_private_key(self, backend):
+        data = load_vectors_from_file(
+            os.path.join("asymmetric", "Ed25519", "ed25519-pkcs8-enc.der"),
+            lambda derfile: derfile.read(),
+            mode="rb"
+        )
+        unencrypted = load_vectors_from_file(
+            os.path.join("asymmetric", "Ed25519", "ed25519-pkcs8.der"),
+            lambda derfile: derfile.read(),
+            mode="rb"
+        )
+        key = load_der_private_key(data, b"password", backend)
+        assert key.private_bytes(
+            Encoding.DER, PrivateFormat.PKCS8, NoEncryption()
+        ) == unencrypted
+
+    def test_load_pem_private_key(self, backend):
+        data = load_vectors_from_file(
+            os.path.join("asymmetric", "Ed25519", "ed25519-pkcs8-enc.pem"),
+            lambda pemfile: pemfile.read(),
+            mode="rb"
+        )
+        unencrypted = load_vectors_from_file(
+            os.path.join("asymmetric", "Ed25519", "ed25519-pkcs8.pem"),
+            lambda pemfile: pemfile.read(),
+            mode="rb"
+        )
+        key = load_pem_private_key(data, b"password", backend)
+        assert key.private_bytes(
+            Encoding.PEM, PrivateFormat.PKCS8, NoEncryption()
+        ) == unencrypted
+
+    @pytest.mark.parametrize(
+        ("key_path", "encoding", "loader"),
+        [
+            (
+                ["Ed25519", "ed25519-pub.pem"],
+                Encoding.PEM,
+                load_pem_public_key
+            ),
+            (
+                ["Ed25519", "ed25519-pub.der"],
+                Encoding.DER,
+                load_der_public_key
+            ),
+        ]
+    )
+    def test_load_public_key(self, key_path, encoding, loader, backend):
+        data = load_vectors_from_file(
+            os.path.join("asymmetric", *key_path),
+            lambda pemfile: pemfile.read(),
+            mode="rb"
+        )
+        public_key = loader(data, backend)
+        assert public_key.public_bytes(
+            encoding, PublicFormat.SubjectPublicKeyInfo
+        ) == data
+
+
+@pytest.mark.supported(
     only_if=lambda backend: backend.x448_supported(),
     skip_message="Requires OpenSSL with X448 support"
 )
diff --git a/tests/wycheproof/test_eddsa.py b/tests/wycheproof/test_eddsa.py
new file mode 100644
index 00000000..40cb49a3
--- /dev/null
+++ b/tests/wycheproof/test_eddsa.py
@@ -0,0 +1,45 @@
+# 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 binascii
+
+import pytest
+
+from cryptography.exceptions import InvalidSignature
+from cryptography.hazmat.backends.interfaces import DHBackend
+from cryptography.hazmat.primitives.asymmetric.ed25519 import (
+    Ed25519PublicKey
+)
+
+
+@pytest.mark.supported(
+    only_if=lambda backend: backend.ed25519_supported(),
+    skip_message="Requires OpenSSL with Ed25519 support"
+)
+@pytest.mark.requires_backend_interface(interface=DHBackend)
+@pytest.mark.wycheproof_tests(
+    "eddsa_test.json",
+)
+def test_ed25519_signature(backend, wycheproof):
+    # We want to fail if/when wycheproof adds more edwards curve tests
+    # so we can add them as well.
+    assert wycheproof.testgroup["key"]["curve"] == "edwards25519"
+
+    key = Ed25519PublicKey.from_public_bytes(
+        binascii.unhexlify(wycheproof.testgroup["key"]["pk"])
+    )
+
+    if wycheproof.valid or wycheproof.acceptable:
+        key.verify(
+            binascii.unhexlify(wycheproof.testcase["sig"]),
+            binascii.unhexlify(wycheproof.testcase["msg"]),
+        )
+    else:
+        with pytest.raises(InvalidSignature):
+            key.verify(
+                binascii.unhexlify(wycheproof.testcase["sig"]),
+                binascii.unhexlify(wycheproof.testcase["msg"]),
+            )