ed448 support (#4610)

* ed448 support

* move the changelog entry

* flake8

3 files changed, 276 insertions, 0 deletions

diff --git a/src/cryptography/hazmat/backends/openssl/backend.py b/src/cryptography/hazmat/backends/openssl/backend.py
index 61f597a3..eab60778 100644
--- a/src/cryptography/hazmat/backends/openssl/backend.py
+++ b/src/cryptography/hazmat/backends/openssl/backend.py
@@ -40,6 +40,9 @@ from cryptography.hazmat.backends.openssl.ec import (
 from cryptography.hazmat.backends.openssl.ed25519 import (
     _ED25519_KEY_SIZE, _Ed25519PrivateKey, _Ed25519PublicKey
 )
+from cryptography.hazmat.backends.openssl.ed448 import (
+    _ED448_KEY_SIZE, _Ed448PrivateKey, _Ed448PublicKey
+)
 from cryptography.hazmat.backends.openssl.encode_asn1 import (
     _CRL_ENTRY_EXTENSION_ENCODE_HANDLERS,
     _CRL_EXTENSION_ENCODE_HANDLERS, _EXTENSION_ENCODE_HANDLERS,
@@ -523,6 +526,9 @@ class Backend(object):
         elif key_type == getattr(self._lib, "EVP_PKEY_X25519", None):
             # EVP_PKEY_X25519 is not present in OpenSSL < 1.1.0
             return _X25519PrivateKey(self, evp_pkey)
+        elif key_type == getattr(self._lib, "EVP_PKEY_ED448", None):
+            # EVP_PKEY_ED448 is not present in OpenSSL < 1.1.1
+            return _Ed448PrivateKey(self, evp_pkey)
         else:
             raise UnsupportedAlgorithm("Unsupported key type.")
 
@@ -563,6 +569,9 @@ class Backend(object):
         elif key_type == getattr(self._lib, "EVP_PKEY_X25519", None):
             # EVP_PKEY_X25519 is not present in OpenSSL < 1.1.0
             return _X25519PublicKey(self, evp_pkey)
+        elif key_type == getattr(self._lib, "EVP_PKEY_ED448", None):
+            # EVP_PKEY_X25519 is not present in OpenSSL < 1.1.1
+            return _Ed448PublicKey(self, evp_pkey)
         else:
             raise UnsupportedAlgorithm("Unsupported key type.")
 
@@ -2232,6 +2241,40 @@ class Backend(object):
         evp_pkey = self._evp_pkey_keygen_gc(self._lib.NID_ED25519)
         return _Ed25519PrivateKey(self, evp_pkey)
 
+    def ed448_supported(self):
+        return not self._lib.CRYPTOGRAPHY_OPENSSL_LESS_THAN_111B
+
+    def ed448_load_public_bytes(self, data):
+        utils._check_bytes("data", data)
+        if len(data) != _ED448_KEY_SIZE:
+            raise ValueError("An Ed448 public key is 57 bytes long")
+
+        evp_pkey = self._lib.EVP_PKEY_new_raw_public_key(
+            self._lib.NID_ED448, 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 _Ed448PublicKey(self, evp_pkey)
+
+    def ed448_load_private_bytes(self, data):
+        utils._check_byteslike("data", data)
+        if len(data) != _ED448_KEY_SIZE:
+            raise ValueError("An Ed448 private key is 57 bytes long")
+
+        data_ptr = self._ffi.from_buffer(data)
+        evp_pkey = self._lib.EVP_PKEY_new_raw_private_key(
+            self._lib.NID_ED448, 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 _Ed448PrivateKey(self, evp_pkey)
+
+    def ed448_generate_key(self):
+        evp_pkey = self._evp_pkey_keygen_gc(self._lib.NID_ED448)
+        return _Ed448PrivateKey(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/ed448.py b/src/cryptography/hazmat/backends/openssl/ed448.py
new file mode 100644
index 00000000..cf2acf83
--- /dev/null
+++ b/src/cryptography/hazmat/backends/openssl/ed448.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.ed448 import (
+    Ed448PrivateKey, Ed448PublicKey
+)
+
+_ED448_KEY_SIZE = 57
+_ED448_SIG_SIZE = 114
+
+
+@utils.register_interface(Ed448PublicKey)
+class _Ed448PublicKey(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 []", _ED448_KEY_SIZE)
+        buflen = self._backend._ffi.new("size_t *", _ED448_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] == _ED448_KEY_SIZE)
+        return self._backend._ffi.buffer(buf, _ED448_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(Ed448PrivateKey)
+class _Ed448PrivateKey(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 []", _ED448_KEY_SIZE)
+        buflen = self._backend._ffi.new("size_t *", _ED448_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] == _ED448_KEY_SIZE)
+        public_bytes = self._backend._ffi.buffer(buf)[:]
+        return self._backend.ed448_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[]", _ED448_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] == _ED448_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 []", _ED448_KEY_SIZE)
+        buflen = self._backend._ffi.new("size_t *", _ED448_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] == _ED448_KEY_SIZE)
+        return self._backend._ffi.buffer(buf, _ED448_KEY_SIZE)[:]
diff --git a/src/cryptography/hazmat/primitives/asymmetric/ed448.py b/src/cryptography/hazmat/primitives/asymmetric/ed448.py
new file mode 100644
index 00000000..939157ab
--- /dev/null
+++ b/src/cryptography/hazmat/primitives/asymmetric/ed448.py
@@ -0,0 +1,79 @@
+# 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 Ed448PublicKey(object):
+    @classmethod
+    def from_public_bytes(cls, data):
+        from cryptography.hazmat.backends.openssl.backend import backend
+        if not backend.ed448_supported():
+            raise UnsupportedAlgorithm(
+                "ed448 is not supported by this version of OpenSSL.",
+                _Reasons.UNSUPPORTED_PUBLIC_KEY_ALGORITHM
+            )
+
+        return backend.ed448_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 Ed448PrivateKey(object):
+    @classmethod
+    def generate(cls):
+        from cryptography.hazmat.backends.openssl.backend import backend
+        if not backend.ed448_supported():
+            raise UnsupportedAlgorithm(
+                "ed448 is not supported by this version of OpenSSL.",
+                _Reasons.UNSUPPORTED_PUBLIC_KEY_ALGORITHM
+            )
+        return backend.ed448_generate_key()
+
+    @classmethod
+    def from_private_bytes(cls, data):
+        from cryptography.hazmat.backends.openssl.backend import backend
+        if not backend.ed448_supported():
+            raise UnsupportedAlgorithm(
+                "ed448 is not supported by this version of OpenSSL.",
+                _Reasons.UNSUPPORTED_PUBLIC_KEY_ALGORITHM
+            )
+
+        return backend.ed448_load_private_bytes(data)
+
+    @abc.abstractmethod
+    def public_key(self):
+        """
+        The Ed448PublicKey derived from the private key.
+        """
+
+    @abc.abstractmethod
+    def sign(self, data):
+        """
+        Signs the data.
+        """
+
+    @abc.abstractmethod
+    def private_bytes(self, encoding, format, encryption_algorithm):
+        """
+        The serialized bytes of the private key.
+        """