def __decrypt(self, text):
bits_text = Converter.to_bin(text)
words = self.__split_into_sub_lists(bits_text, 32)
a = words[0]
b = words[1]
c = words[2]
d = words[3]
for i in range(8, 0, -1):
# 1
sub_key = copy.deepcopy(self.sub_keys[7 * i - 1])
temp = Operation.plus_mod_32(a, sub_key)
temp = self.G_operation(temp, 5)
b = Operation.bit_xor(b, temp)
# 2
sub_key = copy.deepcopy(self.sub_keys[7 * i - 1 - 1])
temp = Operation.plus_mod_32(d, sub_key)
temp = self.G_operation(temp, 21)
c = Operation.bit_xor(c, temp)
# 3
sub_key = copy.deepcopy(self.sub_keys[7 * i - 2 - 1])
temp = Operation.plus_mod_32(b, sub_key)
temp = self.G_operation(temp, 13)
a = Operation.minus_mod_32(a, temp)
# 4
sub_key = copy.deepcopy(self.sub_keys[7 * i - 3 - 1])
temp = Operation.plus_mod_32(b, c)
temp = Operation.plus_mod_32(temp, sub_key)
temp = self.G_operation(temp, 21)
value_i = i % (2**32)
value_i = Converter.int_to_bits(value_i, 32)
e = Operation.bit_xor(temp, value_i)
# 5
b = Operation.plus_mod_32(b, e)
# 6
c = Operation.minus_mod_32(c, e)
# 7
sub_key = copy.deepcopy(self.sub_keys[7 * i - 4 - 1])
temp = Operation.plus_mod_32(c, sub_key)
temp = self.G_operation(temp, 13)
d = Operation.plus_mod_32(d, temp)
# 8
sub_key = copy.deepcopy(self.sub_keys[7 * i - 5 - 1])
temp = Operation.plus_mod_32(a, sub_key)
temp = self.G_operation(temp, 21)
b = Operation.bit_xor(b, temp)
# 9
sub_key = copy.deepcopy(self.sub_keys[7 * i - 6 - 1])
temp = Operation.plus_mod_32(d, sub_key)
temp = self.G_operation(temp, 5)
c = Operation.bit_xor(c, temp)
# 10
a, b = b, a
# 11
c, d = d, c
# 12
a, d = d, a
decoded = c + a + d + b
decoded = Converter.to_string(decoded)
return decoded
def __encrypt(self, text):
bits_text = Converter.to_bin(text) # 16 байт (блок) -> 128 бит
words = self.__split_into_sub_lists(bits_text, 32)
a = words[0]
b = words[1]
c = words[2]
d = words[3]
for i in range(1, 9):
# 1
sub_key = copy.deepcopy(self.sub_keys[7 * i - 6 - 1])
value = Operation.plus_mod_32(a, sub_key)
value = self.G_operation(value, 5)
b = Operation.bit_xor(b, value)
# 2
sub_key = copy.deepcopy(self.sub_keys[7 * i - 5 - 1])
value = Operation.plus_mod_32(d, sub_key)
value = self.G_operation(value, 21)
c = Operation.bit_xor(c, value)
# 3
sub_key = copy.deepcopy(self.sub_keys[7 * i - 4 - 1])
value = Operation.plus_mod_32(b, sub_key)
value = self.G_operation(value, 13)
a = Operation.minus_mod_32(a, value)
# 4
sub_key = copy.deepcopy(self.sub_keys[7 * i - 3 - 1])
value = Operation.plus_mod_32(b, c)
value = Operation.plus_mod_32(value, sub_key)
value = self.G_operation(value, 21)
value_i = i % (2**32)
value_i = Converter.int_to_bits(value_i, 32)
while len(value_i) < 32:
value_i.insert(0, 0)
e = Operation.bit_xor(value, value_i)
# 5
b = Operation.plus_mod_32(b, e)
# 6
c = Operation.minus_mod_32(c, e)
# 7
sub_key = copy.deepcopy(self.sub_keys[7 * i - 2 - 1])
value = Operation.plus_mod_32(c, sub_key)
value = self.G_operation(value, 13)
d = Operation.plus_mod_32(d, value)
# 8
sub_key = copy.deepcopy(self.sub_keys[7 * i - 1 - 1])
value = Operation.plus_mod_32(a, sub_key)
value = self.G_operation(value, 21)
b = Operation.bit_xor(b, value)
# 9
sub_key = copy.deepcopy(self.sub_keys[7 * i - 1])
value = Operation.plus_mod_32(d, sub_key)
value = self.G_operation(value, 5)
c = Operation.bit_xor(c, value)
# 10
a, b = b, a
# 11
c, d = d, c
# 12
b, c = c, b
encrypted = b + d + a + c
encrypted = Converter.to_string(encrypted)
return encrypted
