saymrwulf/cryptography
1
0
Fork 0
mirror of https://github.com/saymrwulf/cryptography.git synced 2026-05-14 20:37:55 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

stop using backend methods for chacha (#3765)

Browse source
This commit is contained in:
Paul Kehrer 2017-07-08 12:36:45 -05:00 committed by Alex Gaynor
parent 9c6352413d
commit bb631441a3
3 changed files with 20 additions and 22 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

15
src/cryptography/hazmat/backends/openssl/aead.py
View file

@ -11,6 +11,15 @@ _ENCRYPT = 1
_DECRYPT = 0
def _aead_cipher_name(cls, key_length):
from cryptography.hazmat.primitives.ciphers.aead import (
ChaCha20Poly1305
)
assert cls is ChaCha20Poly1305
assert key_length == 32 or key_length is None
return b"chacha20-poly1305"
def _aead_setup(backend, cipher_name, key, nonce, tag, tag_len, operation):
evp_cipher = backend._lib.EVP_get_cipherbyname(cipher_name)
backend.openssl_assert(evp_cipher != backend._ffi.NULL)
@ -69,8 +78,9 @@ def _process_data(backend, ctx, data):
return backend._ffi.buffer(buf, outlen[0])[:]
def _encrypt(backend, cipher_name, key, nonce, data, associated_data,
def _encrypt(backend, cipher_cls, key, nonce, data, associated_data,
tag_length):
cipher_name = _aead_cipher_name(cipher_cls, len(key))
ctx = _aead_setup(
backend, cipher_name, key, nonce, None, tag_length, _ENCRYPT
)
@ -91,12 +101,13 @@ def _encrypt(backend, cipher_name, key, nonce, data, associated_data,
return processed_data + tag
def _decrypt(backend, cipher_name, key, nonce, data, associated_data,
def _decrypt(backend, cipher_cls, key, nonce, data, associated_data,
tag_length):
if len(data) < tag_length:
raise InvalidTag
tag = data[-tag_length:]
data = data[:-tag_length]
cipher_name = _aead_cipher_name(cipher_cls, len(key))
ctx = _aead_setup(
backend, cipher_name, key, nonce, tag, tag_length, _DECRYPT
)

18
src/cryptography/hazmat/backends/openssl/backend.py
View file

@ -1924,24 +1924,10 @@ class Backend(object):
self.openssl_assert(res == 1)
return self._ffi.buffer(buf)[:]
def chacha20poly1305_encrypt(self, key, nonce, data, associated_data):
return aead._encrypt(
self, b"chacha20-poly1305", key, nonce, data, associated_data, 16
)
def chacha20poly1305_decrypt(self, key, nonce, data, associated_data):
return aead._decrypt(
self, b"chacha20-poly1305", key, nonce, data, associated_data, 16
)
def aead_cipher_supported(self, cls):
from cryptography.hazmat.primitives.ciphers.aead import (
ChaCha20Poly1305
)
assert cls is ChaCha20Poly1305
cipher_name = aead._aead_cipher_name(cls, None)
return (
self._lib.EVP_get_cipherbyname(b"chacha20-poly1305") !=
self._ffi.NULL
self._lib.EVP_get_cipherbyname(cipher_name) != self._ffi.NULL
)

9
src/cryptography/hazmat/primitives/ciphers/aead.py
View file

@ -7,6 +7,7 @@ from __future__ import absolute_import, division, print_function
import os
from cryptography import exceptions, utils
from cryptography.hazmat.backends.openssl import aead
from cryptography.hazmat.backends.openssl.backend import backend
@ -33,8 +34,8 @@ class ChaCha20Poly1305(object):
associated_data = b""
self._check_params(nonce, data, associated_data)
return backend.chacha20poly1305_encrypt(
self._key, nonce, data, associated_data
return aead._encrypt(
backend, type(self), self._key, nonce, data, associated_data, 16
)
def decrypt(self, nonce, data, associated_data):
@ -42,8 +43,8 @@ class ChaCha20Poly1305(object):
associated_data = b""
self._check_params(nonce, data, associated_data)
return backend.chacha20poly1305_decrypt(
self._key, nonce, data, associated_data
return aead._decrypt(
backend, type(self), self._key, nonce, data, associated_data, 16
)
def _check_params(self, nonce, data, associated_data):