Dump libssl bindings in favour of the new optional cryptg module

This commit is contained in:
Lonami Exo 2018-02-16 18:24:44 +01:00
parent c11aefa95b
commit 030f292203
2 changed files with 64 additions and 167 deletions

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@ -3,86 +3,90 @@ AES IGE implementation in Python. This module may use libssl if available.
""" """
import os import os
import pyaes import pyaes
from . import libssl
try:
import cryptg
except ImportError:
cryptg = None
if libssl.AES is not None: class AES:
# Use libssl if available, since it will be faster """
AES = libssl.AES Class that servers as an interface to encrypt and decrypt
else: text through the AES IGE mode.
# Fallback to a pure Python implementation """
class AES: @staticmethod
def decrypt_ige(cipher_text, key, iv):
""" """
Class that servers as an interface to encrypt and decrypt Decrypts the given text in 16-bytes blocks by using the
text through the AES IGE mode. given key and 32-bytes initialization vector.
""" """
@staticmethod if cryptg:
def decrypt_ige(cipher_text, key, iv): return cryptg.decrypt_ige(cipher_text, key, iv)
"""
Decrypts the given text in 16-bytes blocks by using the
given key and 32-bytes initialization vector.
"""
iv1 = iv[:len(iv) // 2]
iv2 = iv[len(iv) // 2:]
aes = pyaes.AES(key) iv1 = iv[:len(iv) // 2]
iv2 = iv[len(iv) // 2:]
plain_text = [] aes = pyaes.AES(key)
blocks_count = len(cipher_text) // 16
cipher_text_block = [0] * 16 plain_text = []
for block_index in range(blocks_count): blocks_count = len(cipher_text) // 16
for i in range(16):
cipher_text_block[i] = \
cipher_text[block_index * 16 + i] ^ iv2[i]
plain_text_block = aes.decrypt(cipher_text_block) cipher_text_block = [0] * 16
for block_index in range(blocks_count):
for i in range(16):
cipher_text_block[i] = \
cipher_text[block_index * 16 + i] ^ iv2[i]
for i in range(16): plain_text_block = aes.decrypt(cipher_text_block)
plain_text_block[i] ^= iv1[i]
iv1 = cipher_text[block_index * 16:block_index * 16 + 16] for i in range(16):
iv2 = plain_text_block plain_text_block[i] ^= iv1[i]
plain_text.extend(plain_text_block) iv1 = cipher_text[block_index * 16:block_index * 16 + 16]
iv2 = plain_text_block
return bytes(plain_text) plain_text.extend(plain_text_block)
@staticmethod return bytes(plain_text)
def encrypt_ige(plain_text, key, iv):
"""
Encrypts the given text in 16-bytes blocks by using the
given key and 32-bytes initialization vector.
"""
# Add random padding iff it's not evenly divisible by 16 already @staticmethod
if len(plain_text) % 16 != 0: def encrypt_ige(plain_text, key, iv):
padding_count = 16 - len(plain_text) % 16 """
plain_text += os.urandom(padding_count) Encrypts the given text in 16-bytes blocks by using the
given key and 32-bytes initialization vector.
"""
# Add random padding iff it's not evenly divisible by 16 already
if len(plain_text) % 16 != 0:
padding_count = 16 - len(plain_text) % 16
plain_text += os.urandom(padding_count)
iv1 = iv[:len(iv) // 2] if cryptg:
iv2 = iv[len(iv) // 2:] return cryptg.encrypt_ige(plain_text, key, iv)
aes = pyaes.AES(key) iv1 = iv[:len(iv) // 2]
iv2 = iv[len(iv) // 2:]
cipher_text = [] aes = pyaes.AES(key)
blocks_count = len(plain_text) // 16
for block_index in range(blocks_count): cipher_text = []
plain_text_block = list( blocks_count = len(plain_text) // 16
plain_text[block_index * 16:block_index * 16 + 16]
)
for i in range(16):
plain_text_block[i] ^= iv1[i]
cipher_text_block = aes.encrypt(plain_text_block) for block_index in range(blocks_count):
plain_text_block = list(
plain_text[block_index * 16:block_index * 16 + 16]
)
for i in range(16):
plain_text_block[i] ^= iv1[i]
for i in range(16): cipher_text_block = aes.encrypt(plain_text_block)
cipher_text_block[i] ^= iv2[i]
iv1 = cipher_text_block for i in range(16):
iv2 = plain_text[block_index * 16:block_index * 16 + 16] cipher_text_block[i] ^= iv2[i]
cipher_text.extend(cipher_text_block) iv1 = cipher_text_block
iv2 = plain_text[block_index * 16:block_index * 16 + 16]
return bytes(cipher_text) cipher_text.extend(cipher_text_block)
return bytes(cipher_text)

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@ -1,107 +0,0 @@
"""
This module holds an AES IGE class, if libssl is available on the system.
"""
import os
import ctypes
from ctypes.util import find_library
lib = find_library('ssl')
if not lib:
AES = None
else:
""" <aes.h>
# define AES_ENCRYPT 1
# define AES_DECRYPT 0
# define AES_MAXNR 14
struct aes_key_st {
# ifdef AES_LONG
unsigned long rd_key[4 * (AES_MAXNR + 1)];
# else
unsigned int rd_key[4 * (AES_MAXNR + 1)];
# endif
int rounds;
};
typedef struct aes_key_st AES_KEY;
int AES_set_encrypt_key(const unsigned char *userKey, const int bits,
AES_KEY *key);
int AES_set_decrypt_key(const unsigned char *userKey, const int bits,
AES_KEY *key);
void AES_ige_encrypt(const unsigned char *in, unsigned char *out,
size_t length, const AES_KEY *key,
unsigned char *ivec, const int enc);
"""
_libssl = ctypes.cdll.LoadLibrary(lib)
AES_MAXNR = 14
AES_ENCRYPT = ctypes.c_int(1)
AES_DECRYPT = ctypes.c_int(0)
class AES_KEY(ctypes.Structure):
"""Helper class representing an AES key"""
_fields_ = [
('rd_key', ctypes.c_uint32 * (4*(AES_MAXNR + 1))),
('rounds', ctypes.c_uint),
]
class AES:
"""
Class that servers as an interface to encrypt and decrypt
text through the AES IGE mode, using the system's libssl.
"""
@staticmethod
def decrypt_ige(cipher_text, key, iv):
"""
Decrypts the given text in 16-bytes blocks by using the
given key and 32-bytes initialization vector.
"""
aeskey = AES_KEY()
ckey = (ctypes.c_ubyte * len(key))(*key)
cklen = ctypes.c_int(len(key)*8)
cin = (ctypes.c_ubyte * len(cipher_text))(*cipher_text)
ctlen = ctypes.c_size_t(len(cipher_text))
cout = (ctypes.c_ubyte * len(cipher_text))()
civ = (ctypes.c_ubyte * len(iv))(*iv)
_libssl.AES_set_decrypt_key(ckey, cklen, ctypes.byref(aeskey))
_libssl.AES_ige_encrypt(
ctypes.byref(cin),
ctypes.byref(cout),
ctlen,
ctypes.byref(aeskey),
ctypes.byref(civ),
AES_DECRYPT
)
return bytes(cout)
@staticmethod
def encrypt_ige(plain_text, key, iv):
"""
Encrypts the given text in 16-bytes blocks by using the
given key and 32-bytes initialization vector.
"""
# Add random padding iff it's not evenly divisible by 16 already
if len(plain_text) % 16 != 0:
padding_count = 16 - len(plain_text) % 16
plain_text += os.urandom(padding_count)
aeskey = AES_KEY()
ckey = (ctypes.c_ubyte * len(key))(*key)
cklen = ctypes.c_int(len(key)*8)
cin = (ctypes.c_ubyte * len(plain_text))(*plain_text)
ctlen = ctypes.c_size_t(len(plain_text))
cout = (ctypes.c_ubyte * len(plain_text))()
civ = (ctypes.c_ubyte * len(iv))(*iv)
_libssl.AES_set_encrypt_key(ckey, cklen, ctypes.byref(aeskey))
_libssl.AES_ige_encrypt(
ctypes.byref(cin),
ctypes.byref(cout),
ctlen,
ctypes.byref(aeskey),
ctypes.byref(civ),
AES_ENCRYPT
)
return bytes(cout)