def str2hex(_str):
"""
the following function will be used to convert
a strin chr message into hex-digits string
"""
str_bin = pad_to_block(string_to_bits(_str), ASCII_BITS)
return hex(int(display_bits(str_bin), 2))[2:-1].zfill(len(str_bin) / 4)
def str2hex(_str): """ the following function will be used to convert a strin chr message into hex-digits string """ str_bin = pad_to_block(string_to_bits(_str), ASCII_BITS) return hex(int(display_bits(str_bin), 2))[2:-1].zfill(len(str_bin) / 4)
def test_counter_block_function():
hex_nonce = ''.join('00 6C B6 DB'.split())
print hex_nonce
hex_iv = ''.join('C0 54 3B 59 DA 48 D9 0B'.split())
print hex_iv
bin_nonce = pad_to_block(convert_to_bits(int(hex_nonce, 16)), len(hex_nonce)*4)
print bin_nonce
bin_iv = pad_to_block(convert_to_bits(int(hex_iv, 16)), len(hex_iv)*4)
ctr = Counter.new(32)
def counter_block():
return bits_to_string(bin_nonce + bin_iv + string_to_bits(ctr()))
final_str = hex(int(display_bits(string_to_bits(counter_block())), 2))[2:-1].zfill(32)
print final_str
print final_str == ''.join('00 6C B6 DB C0 54 3B 59 DA 48 D9 0B 00 00 00 01'.lower().split())
final_str = hex(int(display_bits(string_to_bits(counter_block())), 2))[2:-1].zfill(32)
print final_str
print final_str == ''.join('00 6C B6 DB C0 54 3B 59 DA 48 D9 0B 00 00 00 02'.lower().split())
def hexbinstrxor(_hex, _bin):
# convert both the hex and bin string into ASCII-characters string
str1 = bits_to_string(
pad_to_block(convert_to_bits(int(_hex, 16)),
len(_hex) * 4))
str2 = bits_to_string([b for b in _bin])
size = min(len(str1), len(str2))
return ''.join(
[chr(ord(c1) ^ ord(c2)) for c1, c2 in zip(str1[:size], str2[:size])])
def hex2str(_hex):
"""
the following function will be used to convert
a hex message into a string of characters
"""
if not is_hex(_hex):
raise Exception('Key to AES_CTR must be hex-digits')
hex_int = int(_hex, 16)
hex_bin = convert_to_bits(hex_int)
return bits_to_string(pad_to_block(hex_bin, len(_hex) * 4))
def hex2str(_hex):
"""
the following function will be used to convert
a hex message into a string of characters
"""
if not is_hex(_hex):
raise Exception('Key to AES_CTR must be hex-digits')
hex_int = int(_hex, 16)
hex_bin = convert_to_bits(hex_int)
return bits_to_string(pad_to_block(hex_bin, len(_hex) * 4))
def hex_blks2str(_blks_list):
"""
the following function will be used to convert hex-digits blocks
of the plaintext into a single string of ASCII-characters
"""
list_str = ''.join((' '.join(_blks_list)).split())
num_hex_digits = len(list_str)
hex_int = int(list_str, 16)
hex_bin = convert_to_bits(hex_int)
return bits_to_string(pad_to_block(hex_bin, num_hex_digits * 4))
def msg_hex2str(self):
"""
the following function will be used to convert
a hex message into a string of characters
"""
if not self.is_empty():
hex_int = int(self.data, 16)
hex_bin = convert_to_bits(hex_int)
return bits_to_string(pad_to_block(hex_bin, ASCII_BITS))
else:
raise Exception('Message is EMPTY')
def msg_hex2str(self):
"""
the following function will be used to convert
a hex message into a string of characters
"""
if not self.is_empty():
hex_int = int(self.data, 16)
hex_bin = convert_to_bits(hex_int)
return bits_to_string(pad_to_block(hex_bin, ASCII_BITS))
else:
raise Exception('Message is EMPTY')
def decode(self, ciphertext, hex_iv): """ ciphertext: a string representing the ciphertext which will be decrypted hex_iv: a hex-digit string representing the initialization vector return hex-digit string representing the plaintext """ bin_iv = pad_to_block(convert_to_bits(int(hex_iv, 16)), len(hex_iv)*4) ctr = Counter.new(32) # counter is 32-bits (4-bytes) long def counter_block(): return bits_to_string(self.bin_nonce + bin_iv + string_to_bits(ctr())) decoder = AES.new(self.key, AES.MODE_CTR, counter=counter_block) plaintext = decoder.decrypt(ciphertext) return str2hex(plaintext)
def test_counter_block_function():
hex_nonce = ''.join('00 6C B6 DB'.split())
print hex_nonce
hex_iv = ''.join('C0 54 3B 59 DA 48 D9 0B'.split())
print hex_iv
bin_nonce = pad_to_block(convert_to_bits(int(hex_nonce, 16)),
len(hex_nonce) * 4)
print bin_nonce
bin_iv = pad_to_block(convert_to_bits(int(hex_iv, 16)), len(hex_iv) * 4)
ctr = Counter.new(32)
def counter_block():
return bits_to_string(bin_nonce + bin_iv + string_to_bits(ctr()))
final_str = hex(int(display_bits(string_to_bits(counter_block())),
2))[2:-1].zfill(32)
print final_str
print final_str == ''.join(
'00 6C B6 DB C0 54 3B 59 DA 48 D9 0B 00 00 00 01'.lower().split())
final_str = hex(int(display_bits(string_to_bits(counter_block())),
2))[2:-1].zfill(32)
print final_str
print final_str == ''.join(
'00 6C B6 DB C0 54 3B 59 DA 48 D9 0B 00 00 00 02'.lower().split())
def decode(self, ciphertext, hex_iv):
"""
ciphertext: a string representing the ciphertext which will be decrypted
hex_iv: a hex-digit string representing the initialization vector
return hex-digit string representing the plaintext
"""
bin_iv = pad_to_block(convert_to_bits(int(hex_iv, 16)),
len(hex_iv) * 4)
ctr = Counter.new(32) # counter is 32-bits (4-bytes) long
def counter_block():
return bits_to_string(self.bin_nonce + bin_iv +
string_to_bits(ctr()))
decoder = AES.new(self.key, AES.MODE_CTR, counter=counter_block)
plaintext = decoder.decrypt(ciphertext)
return str2hex(plaintext)
def __init__(self, hex_key, hex_nonce): self.key = hex2str(hex_key) self.bin_nonce = pad_to_block(convert_to_bits(int(hex_nonce, 16)), len(hex_nonce)*4)
def __init__(self, hex_key, hex_nonce):
self.key = hex2str(hex_key)
self.bin_nonce = pad_to_block(convert_to_bits(int(hex_nonce, 16)),
len(hex_nonce) * 4)
def message_value(message):
message = bits_to_string(pad_to_block(convert_to_bits(message), 8))
return bill_value(message)