def set_key(self, key):
if __debug__:
# Insecure.
assert len(key) >= self.digest_size
if len(key) > self.block_size:
# Key is too big. Hash it and use the result as the key.
# This really isn't necessary because we're certain that the key
# is going to be the correct size. However, I put it in here
# for completeness with the HMAC spec.
import sys
sys.stderr.write('WARNING: Unexecpted HMAC key size!!!\n')
h = self.get_hash_object()
self.key = h.update(key).digest()
else:
self.key = key
ipad = '\x36' * self.block_size
opad = '\x5C' * self.block_size
padded_key = self.key + '\0' * (self.block_size - len(self.key))
self._enc_ipad = str_xor(padded_key, ipad)
self._enc_opad = str_xor(padded_key, opad)
def set_key(self, key):
if __debug__:
# Insecure.
assert len(key) >= self.digest_size
if len(key) > self.block_size:
# Key is too big. Hash it and use the result as the key.
# This really isn't necessary because we're certain that the key
# is going to be the correct size. However, I put it in here
# for completeness with the HMAC spec.
import sys
sys.stderr.write('WARNING: Unexecpted HMAC key size!!!\n')
h = self.get_hash_object()
self.key = h.update(key).digest()
else:
self.key = key
ipad = '\x36' * self.block_size
opad = '\x5C' * self.block_size
padded_key = self.key + '\0' * (self.block_size - len(self.key))
self._enc_ipad = str_xor(padded_key, ipad)
self._enc_opad = str_xor(padded_key, opad)
def des_ede3_cbc_decrypt(data, iv, key):
assert (len(data) % 8 == 0), 'Data block must be a multiple of 8: %i' % len(data)
key1 = DES.new(key[0:8], DES.MODE_ECB)
key2 = DES.new(key[8:16], DES.MODE_ECB)
key3 = DES.new(key[16:24], DES.MODE_ECB)
# Outer-CBC Mode
# 8-byte blocks
result = []
prev = iv
for i in xrange(0, len(data), 8):
block = data[i:i + 8]
value = key1.decrypt(
key2.encrypt(
key3.decrypt(block)))
result.append(str_xor(prev, value))
prev = block
return ''.join(result)
