[irc/quakenet/qwebirc.git] / qwebirc / util / ciphers.py

# write me

def xor(a, b):
  assert(len(a) == len(b))
  out = []
  for i in range(0, len(a)):
    out.append(chr(ord(a[i]) ^ ord(b[i])))

  return "".join(out)

class CBC:
  def __init__(self, cipher, iv):
    self.__cipher = cipher
    self.__prevblock = False
    self.__iv = iv

  def encrypt(self, block):
    if not self.__prevblock:
      i = self.__iv
    else:
      i = self.__prevblock

    c = xor(block, i)

    self.__prevblock = self.__cipher.encrypt(c)
    return self.__prevblock

  def decrypt(self, block):
    c = self.__cipher.decrypt(block)
    if not self.__prevblock:
      i = self.__iv
    else:
      i = self.__prevblock

    c = xor(c, i)

    self.__prevblock = block
    return c
Commit	Line	Data
ace37679 CP	1	# write me
	2
	3	def xor(a, b):
	4	assert(len(a) == len(b))
	5	out = []
	6	for i in range(0, len(a)):
	7	out.append(chr(ord(a[i]) ^ ord(b[i])))
	8
	9	return "".join(out)
	10
	11	class CBC:
	12	def __init__(self, cipher, iv):
	13	self.__cipher = cipher
	14	self.__prevblock = False
	15	self.__iv = iv
	16
	17	def encrypt(self, block):
	18	if not self.__prevblock:
	19	i = self.__iv
	20	else:
	21	i = self.__prevblock
	22
	23	c = xor(block, i)
	24
	25	self.__prevblock = self.__cipher.encrypt(c)
	26	return self.__prevblock
	27
	28	def decrypt(self, block):
	29	c = self.__cipher.decrypt(block)
	30	if not self.__prevblock:
	31	i = self.__iv
	32	else:
	33	i = self.__prevblock
	34
	35	c = xor(c, i)
	36
	37	self.__prevblock = block
	38	return c