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encrypt.py is renamed to cryptor.py (#780)

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Zou Yong 2017-03-05 01:09:40 +08:00 committed by mengskysama
parent 445a3c9c7e
commit d6b40efa5d
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shadowsocks/encrypt.py
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#!/usr/bin/env python
#
# Copyright 2012-2015 clowwindy
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
from __future__ import absolute_import, division, print_function, \
with_statement
import os
import sys
import hashlib
import logging
from shadowsocks import common
from shadowsocks.crypto import rc4_md5, openssl, sodium, table
method_supported = {}
method_supported.update(rc4_md5.ciphers)
method_supported.update(openssl.ciphers)
method_supported.update(sodium.ciphers)
method_supported.update(table.ciphers)
def random_string(length):
return os.urandom(length)
cached_keys = {}
def try_cipher(key, method=None):
Encryptor(key, method)
def EVP_BytesToKey(password, key_len, iv_len):
# equivalent to OpenSSL's EVP_BytesToKey() with count 1
# so that we make the same key and iv as nodejs version
cached_key = '%s-%d-%d' % (password, key_len, iv_len)
r = cached_keys.get(cached_key, None)
if r:
return r
m = []
i = 0
while len(b''.join(m)) < (key_len + iv_len):
md5 = hashlib.md5()
data = password
if i > 0:
data = m[i - 1] + password
md5.update(data)
m.append(md5.digest())
i += 1
ms = b''.join(m)
key = ms[:key_len]
iv = ms[key_len:key_len + iv_len]
cached_keys[cached_key] = (key, iv)
return key, iv
class Encryptor(object):
def __init__(self, password, method):
self.password = password
self.key = None
self.method = method
self.iv_sent = False
self.cipher_iv = b''
self.decipher = None
self.decipher_iv = None
method = method.lower()
self._method_info = self.get_method_info(method)
if self._method_info:
self.cipher = self.get_cipher(password, method, 1,
random_string(self._method_info[1]))
else:
logging.error('method %s not supported' % method)
sys.exit(1)
def get_method_info(self, method):
method = method.lower()
m = method_supported.get(method)
return m
def iv_len(self):
return len(self.cipher_iv)
def get_cipher(self, password, method, op, iv):
password = common.to_bytes(password)
m = self._method_info
if m[0] > 0:
key, iv_ = EVP_BytesToKey(password, m[0], m[1])
else:
# key_length == 0 indicates we should use the key directly
key, iv = password, b''
self.key = key
iv = iv[:m[1]]
if op == 1:
# this iv is for cipher not decipher
self.cipher_iv = iv[:m[1]]
return m[2](method, key, iv, op)
def encrypt(self, buf):
if len(buf) == 0:
return buf
if self.iv_sent:
return self.cipher.update(buf)
else:
self.iv_sent = True
return self.cipher_iv + self.cipher.update(buf)
def decrypt(self, buf):
if len(buf) == 0:
return buf
if self.decipher is None:
decipher_iv_len = self._method_info[1]
decipher_iv = buf[:decipher_iv_len]
self.decipher_iv = decipher_iv
self.decipher = self.get_cipher(self.password, self.method, 0,
iv=decipher_iv)
buf = buf[decipher_iv_len:]
if len(buf) == 0:
return buf
return self.decipher.update(buf)
def gen_key_iv(password, method):
method = method.lower()
(key_len, iv_len, m) = method_supported[method]
key = None
if key_len > 0:
key, _ = EVP_BytesToKey(password, key_len, iv_len)
else:
key = password
iv = random_string(iv_len)
return key, iv, m
def encrypt_all_m(key, iv, m, method, data):
result = []
result.append(iv)
cipher = m(method, key, iv, 1)
result.append(cipher.update(data))
return b''.join(result)
def dencrypt_all(password, method, data):
result = []
method = method.lower()
(key_len, iv_len, m) = method_supported[method]
key = None
if key_len > 0:
key, _ = EVP_BytesToKey(password, key_len, iv_len)
else:
key = password
iv = data[:iv_len]
data = data[iv_len:]
cipher = m(method, key, iv, 0)
result.append(cipher.update(data))
return b''.join(result), key, iv
def encrypt_all(password, method, op, data):
result = []
method = method.lower()
(key_len, iv_len, m) = method_supported[method]
key = None
if key_len > 0:
key, _ = EVP_BytesToKey(password, key_len, iv_len)
else:
key = password
if op:
iv = random_string(iv_len)
result.append(iv)
else:
iv = data[:iv_len]
data = data[iv_len:]
cipher = m(method, key, iv, op)
result.append(cipher.update(data))
return b''.join(result)
CIPHERS_TO_TEST = [
'aes-128-cfb',
'aes-256-cfb',
'rc4-md5',
'salsa20',
'chacha20',
'table',
]
def test_encryptor():
from os import urandom
plain = urandom(10240)
for method in CIPHERS_TO_TEST:
logging.warn(method)
encryptor = Encryptor(b'key', method)
decryptor = Encryptor(b'key', method)
cipher = encryptor.encrypt(plain)
plain2 = decryptor.decrypt(cipher)
assert plain == plain2
def test_encrypt_all():
from os import urandom
plain = urandom(10240)
for method in CIPHERS_TO_TEST:
logging.warn(method)
cipher = encrypt_all(b'key', method, 1, plain)
plain2 = encrypt_all(b'key', method, 0, cipher)
assert plain == plain2
def test_encrypt_all_m():
from os import urandom
plain = urandom(10240)
for method in CIPHERS_TO_TEST:
logging.warn(method)
key, iv, m = gen_key_iv(b'key', method)
cipher = encrypt_all_m(key, iv, m, method, plain)
plain2, key, iv = dencrypt_all(b'key', method, cipher)
assert plain == plain2
if __name__ == '__main__':
test_encrypt_all()
test_encryptor()
test_encrypt_all_m()