DES加密算法
Posted 向阳-Y.
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from bitarray import bitarray
class MyDES:
def __init__(self):
self.child_keys = []
@staticmethod
def _bit_encode(s: str) -> str:
"""
将字符串转换为01字符串的形式
"""
return bitarray(
''.join([bin(int('1' + hex(c)[2:], 16))[3:]
for c in s.encode('utf-8')])).to01()
@staticmethod
def _bit_decode(s: list):
return ''.join([chr(i) for i in [int(b, 2) for b in s]])
@staticmethod
def _negate(s: str):
result = ""
try:
for i in s:
result += '0' if i == '1' else '1'
return result
except:
print("密钥错误")
raise
@staticmethod
def _replace_block(block: str, replace_table: tuple) -> str:
"""
对单个块进行置换
Args:
block: str, 要进行转换的64位长的01字符串
replace_table: 转换表
Return:
返回转换后的字符串
"""
result = ""
for i in replace_table:
try:
result += block[i - 1]
except IndexError:
print(i)
# print(f"block= {block}, len={len(block)}")
raise
return result
def _processing_encode_input(self, enter: str) -> list:
"""
将输入的字符串转换为二进制形式，并没64位为一组进行分割
"""
result = []
bit_string = self._bit_encode(enter)
# 如果长度不能被64整除，就补零
if len(bit_string) % 64 != 0:
for i in range(64 - len(bit_string) % 64):
bit_string += '0'
for i in range(len(bit_string) // 64):
result.append(bit_string[i * 64: i * 64 + 64])
# print(f"转换为二进制后的初始明文： {result}")
return result
@staticmethod
def _processing_decode_input(enter: str) -> list:
result = []
try:
input_list = enter.split("0x")[1:]
int_list = [int("0x" + i, 16) for i in input_list]
for i in int_list:
bin_data = str(bin(i))[2:]
while len(bin_data) < 64:
bin_data = '0' + bin_data
result.append(bin_data)
return result
except Exception as e:
raise
def _key_conversion(self, key: str):
"""
将64位原始密钥转换为56位的密钥，并进行一次置换
"""
key = self._bit_encode(key)
while len(key) < 64:
key += '0'
first_key = key[:64]
key_replace_table = (
57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18,
10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36,
63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22,
14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4
)
return self._replace_block(first_key, key_replace_table)
def _spin_key(self, key: str):
"""
旋转获得子密钥
"""
kc = self._key_conversion(key)
first, second = kc[0: 28], kc[28: 56]
spin_table = (1, 2, 4, 6, 8, 10, 12, 14, 15, 17, 19, 21, 23, 25, 27, 28)
for i in range(1, 17):
first_after_spin = first[spin_table[i - 1]:] + first[:spin_table[i - 1]]
second_after_spin = second[spin_table[i - 1]:] + second[:spin_table[i - 1]]
# print(f"旋转后的key： left: {first_after_spin}, right: {second_after_spin}")
yield first_after_spin + second_after_spin
def _key_selection_replacement(self, key: str):
"""
通过选择置换得到48位的子密钥
"""
# 先置空
self.child_keys = []
key_select_table = (
14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10,
23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2,
41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48,
44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32
)
for child_key56 in self._spin_key(key):
self.child_keys.append(self._replace_block(child_key56, key_select_table))
def _init_replace_block(self, block: str):
"""
对一个块进行初态置换
"""
replace_table = (
58, 50, 42, 34, 26, 18, 10, 2,
60, 52, 44, 36, 28, 20, 12, 4,
62, 54, 46, 38, 30, 22, 14, 6,
64, 56, 48, 40, 32, 24, 16, 8,
57, 49, 41, 33, 25, 17, 9, 1,
59, 51, 43, 35, 27, 19, 11, 3,
61, 53, 45, 37, 29, 21, 13, 5,
63, 55, 47, 39, 31, 23, 15, 7
)
return self._replace_block(block, replace_table)
def _end_replace_block(self, block: str) -> str:
"""
对某一个块进行终态转换
"""
replace_table = (
40, 8, 48, 16, 56, 24, 64, 32,
39, 7, 47, 15, 55, 23, 63, 31,
38, 6, 46, 14, 54, 22, 62, 30,
37, 5, 45, 13, 53, 21, 61, 29,
36, 4, 44, 12, 52, 20, 60, 28,
35, 3, 43, 11, 51, 19, 59, 27,
34, 2, 42, 10, 50, 18, 58, 26,
33, 1, 41, 9, 49, 17, 57, 25
)
return self._replace_block(block, replace_table)
@staticmethod
def _block_extend(block: str) -> str:
"""
拓展置换
"""
extended_block = ""
extend_table = (
32, 1, 2, 3, 4, 5,
4, 5, 6, 7, 8, 9,
8, 9, 10, 11, 12, 13,
12, 13, 14, 15, 16, 17,
16, 17, 18, 19, 20, 21,
20, 21, 22, 23, 24, 25,
24, 25, 26, 27, 28, 29,
28, 29, 30, 31, 32, 1
)
for i in extend_table:
extended_block += block[i - 1]
return extended_block
@staticmethod
def _not_or(a: str, b: str) -> str:
"""
对两个01字符串做异或
"""
result = ""
size = len(a) if len(a) < len(a) else len(b)
for i in range(size):
result += '0' if a[i] == b[i] else '1'
return result
def _s_box_replace(self, block48: str) -> str:
"""
S盒置换，将48位的输入转换为32位输出
"""
s_box_table = (
(
(14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7),
(0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8),
(4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0),
(15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13),
),
(
(15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10),
(3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5),
(0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15),
(13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9),
),
(
(10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8),
(13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1),
(13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5,以上是关于DES加密算法的主要内容，如果未能解决你的问题，请参考以下文章