一、加密
1、秘钥处理
DES算法会先对64位密钥进行处理生成48位子密钥后再参与到算法的轮操作中，在每一轮的迭代过程中，使用不同的子密钥。其中的处理包括置换选择、循环左移、压缩置换。
1.1 置换选择
DES秘钥有64位，其中每8位有一个校验位，所以有56位的子密钥。根据下表生成56位密钥，并将置换后的56位密钥分成两部分C0和D0，每部分28位：
注意：这里的数字表示的是原数据的位置，不是数据，例：把第57位放在第1位
# 置换函数，用于密钥置换、IP置换、P置换等
def __substitution(self, table: str, self_table: list) -> str:
"""
:param table: 需要进行置换的列表,是一个01字符串
:param self_table: 置换表，在__init__中初始化了
:return: 返回置换后的01字符串
"""
sub_result = ""
for i in self_table:
sub_result += table[i - 1]
return sub_result
# 返回加密过程中16轮的子密钥
def __get_key_list(self):
"""
:return: 返回加密过程中16轮的子密钥
"""
key = self.__substitution(self.K, self.k1) # 置换
left_key = key[0:28]
right_key = key[28:56]
keys = []
for i in range(1, 17): # 循环左移
move = self.k0[i - 1]
move_left = left_key[move:28] + left_key[0:move]
move_right = right_key[move:28] + right_key[0:move]
left_key = move_left
right_key = move_right
move_key = left_key + right_key
ki = self.__substitution(move_key, self.k2) # 压缩置换
keys.append(ki)
return keys def key_conversion(self, key):
"""
将64位原始密钥转换为56位的密钥，并进行一次置换
"""
first_key = key
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)
1.2 循环左移
将C0和D0进行循环左移变化(注：每轮循环左移的位数由轮数决定（如下图）)，变换后生成C1和D1，然后C1和D1合并。
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
1.3 压缩置换
移动后，从56位中选出48位。这个过程中，既置换了每位的顺序，又选择了子密钥，因此称为压缩置换。压缩置换规则如PC-2表（注意表中没有9，18，22，25，35，38，43和54这8位）
压缩置换后的48位子密钥将参与到轮操作中，而C1、D1也将再进行左移和置换后得到下一轮的子密钥。
def key_selection_replacement(self, key: str):
"""
通过选择置换得到48位的子密钥
"""
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))
# 置换函数，用于密钥置换、IP置换、P置换等
def __substitution(self, table: str, self_table: list) -> str:
"""
:param table: 需要进行置换的列表,是一个01字符串
:param self_table: 置换表，在__init__中初始化了
:return: 返回置换后的01字符串
"""
sub_result = ""
for i in self_table:
sub_result += table[i - 1]
return sub_result
# 返回加密过程中16轮的子密钥
def __get_key_list(self):
"""
:return: 返回加密过程中16轮的子密钥
"""
key = self.__substitution(self.K, self.k1) # 置换
left_key = key[0:28]
right_key = key[28:56]
keys = []
for i in range(1, 17): # 循环左移
move = self.k0[i - 1]
move_left = left_key[move:28] + left_key[0:move]
move_right = right_key[move:28] + right_key[0:move]
left_key = move_left
right_key = move_right
move_key = left_key + right_key
ki = self.__substitution(move_key, self.k2) # 压缩置换
keys.append(ki)
return keys2.明文处理
2.1 将明文变为二进制
将字符串的明文转换为二进制，按64位一组，分成若干组，如果不够64位，就补零。
from bitarray import bitarray
@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()
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
2.2 置换IP
IP置换目的是将输入的64位明文M按位重新组合，并把输出分为L0、R0两部分，每部分各长32位。置换规则如下表所示：
@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 _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)
2.3 16轮轮函数
每一轮循环加密的过程为：
- 将初态置换后或上一次循环后得到的各32位的子块Left和Right
- Right经过f函数转换后得到一个32位的串，这个串与Left做异或后得到下一轮循环的Right
- 将这一轮原视的Right作为下一轮的Left
- 拼接Left和Right,进行下一轮循环
def iteration(self, block: str, key: str) -> str:
for i in range(16):
# 分成左右两个子块
left, right = block[0: 32], block[32: 64]
# 将这一轮原视的Right作为下一轮的Left
next_left = right
# f函数
f_result = self._f_function(right, i)
# f函数的输出与left做异或得到下一轮的right
right = self._not_or(left, f_result)
# 拼接，准备进行下一轮
block = next_left + right
return block[32:] + block[:32]
2.3.1 扩展置换
将一个32位的串根据【拓展置换表】转换为48位，具体就是将32位的数据分成4*8小块，每个小块拓展为6位。
拓展置换表中，每一行代表拓展后的一个小块，内部数字表示原来子块中01的位置，其实就是在每一个小块前面加上前一个小块的最后一个字符，后面加上下一个小块的第一个字符。
扩展置换目的有两个：生成与密钥相同长度的数据以进行异或运算；提供更长的结果，在后续的替代运算中可以进行压缩。
@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
扩展置换之后，右半部分R0变为48位，与子密钥进行异或操作。
2.3.2 S盒置换
1.扩展置换之后，右半部分R0变为48位，与子密钥进行异或操作。
2.将48位分为8组，每组6位，然后将第一位和第六位合在一起换算为十进制数H，中间六位换算为十进制数L，然后用S盒中H行L列的4位二进制数置换初始的6位，总共有8个S盒。意思就是，8组6位通过8个S盒变为8组4位。
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, 10, 14, 7),
(1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12),
),
(
(7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15),
(13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9),
(10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4),
(3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14),
),
(
(2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9),
(14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6),
(4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14),
(11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3),
),
(
(12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11),
(10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8),
(9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6),
(4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13),
),
(
(4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1),
(13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6),
(1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2),
(6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12),
),
(
(13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7),
(1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2),
(7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8),
(2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11),
)
)
result = ""
for i in range(8):
row_bit = (block48[i * 6] + block48[i * 6 + 5]).encode("utf-8")
line_bit = (block48[i * 6 + 1: i * 6 + 5]).encode("utf-8")
row = int(row_bit, 2)
line = int(line_bit, 2)
# print(f"第{row}行， 第{line}列")
data = s_box_table[i][row][line]
no_full = str(bin(data))[2:]
while len(no_full) < 4:
no_full = '0' + no_full
result += no_full
return result
2.3.3 P盒置换
使用P盒置换表进行混淆
def p_box_replacement(self, block32: str) -> str:
"""
P盒置换
Return:
返回经过P盒置换后的32位01串
"""
p_box_replace_table = (
16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10,
2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25,
)
return self.replace_block(block32, p_box_replace_table)
2.4 IP逆置换
与初态置换表不一样
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)
二、解密
解密使用与加密相同的算法，只不过使用子密钥的顺序不同而已，加密过程第一轮循环使用key1 解密过程第一轮循环使用key16,可以在循环加密处添加一个标志位完成.
三、python脚本
import binascii
class ArrangeSimpleDES():
def __init__(self):
# 出初始化DES加密的参数
self.ip = [
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,
] # ip置换
self.ip1 = [
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,
] # 逆ip置换
self.E = [
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,
] # E置换(扩展置换)，将32位明文置换位48位
self.P = [
16, 7, 20, 21, 29, 12, 28, 17,
1, 15, 23, 26, 5, 18, 31, 10,
2, 8, 24, 14, 32, 27, 3, 9,
19, 13, 30, 6, 22, 11, 4, 25,
] # P置换，对经过S盒之后的数据再次进行置换
# 设置默认密钥
self.K = '0111010001101000011010010111001101101001011100110110100101110110'
self.k1 = [
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,
] # 密钥的K1初始置换
self.k2 = [
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,
]
self.k0 = [1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1, ] # 秘钥循环移位的位数
self.S = [
[
0xe, 0x4, 0xd, 0x1, 0x2, 0xf, 0xb, 0x8, 0x3, 0xa, 0x6, 0xc, 0x5, 0x9, 0x0, 0x7,
0x0, 0xf, 0x7, 0x4, 0xe, 0x2, 0xd, 0x1, 0xa, 0x6, 0xc, 0xb, 0x9, 0x5, 0x3, 0x8,
0x4, 0x1, 0xe, 0x8, 0xd, 0x6, 0x2, 0xb, 0xf, 0xc, 0x9, 0x7, 0x3, 0xa, 0x5, 0x0,
0xf, 0xc, 0x8, 0x2, 0x4, 0x9, 0x1, 0x7, 0x5, 0xb, 0x3, 0xe, 0xa, 0x0, 0x6, 0xd,
],
[
0xf, 0x1, 0x8, 0xe, 0x6, 0xb, 0x3, 0x4, 0x9, 0x7, 0x2, 0xd, 0xc, 0x0, 0x5, 0xa,
0x3, 0xd, 0x4, 0x7, 0xf, 0x2, 0x8, 0xe, 0xc, 0x0, 0x1, 0xa, 0x6, 0x9, 0xb, 0x5,
0x0, 0xe, 0x7, 0xb, 0xa, 0x4, 0xd, 0x1, 0x5, 0x8, 0xc, 0x6, 0x9, 0x3, 0x2, 0xf,
0xd, 0x8, 0xa, 0x1, 0x3, 0xf, 0x4, 0x2, 0xb, 0x6, 0x7, 0xc, 0x0, 0x5, 0xe, 0x9,
],
[
0xa, 0x0, 0x9, 0xe, 0x6, 0x3, 0xf, 0x5, 0x1, 0xd, 0xc, 0x7, 0xb, 0x4, 0x2, 0x8,
0xd, 0x7, 0x0, 0x9, 0x3, 0x4, 0x6, 0xa, 0x2, 0x8, 0x5, 0xe, 0xc, 0xb, 0xf, 0x1,
0xd, 0x6, 0x4, 0x9, 0x8, 0xf, 0x3, 0x0, 0xb, 0x1, 0x2, 0xc, 0x5, 0xa, 0xe, 0x7,
0x1, 0xa, 0xd, 0x0, 0x6, 0x9, 0x8, 0x7, 0x4, 0xf, 0xe, 0x3, 0xb, 0x5, 0x2, 0xc,
],
[
0x7, 0xd, 0xe, 0x3, 0x0, 0x6, 0x9, 0xa, 0x1, 0x2, 0x8, 0x5, 0xb, 0xc, 0x4, 0xf,
0xd, 0x8, 0xb, 0x5, 0x6, 0xf, 0x0, 0x3, 0x4, 0x7, 0x2, 0xc, 0x1, 0xa, 0xe, 0x9,
0xa, 0x6, 0x9, 0x0, 0xc, 0xb, 0x7, 0xd, 0xf, 0x1, 0x3, 0xe, 0x5, 0x2, 0x8, 0x4,
0x3, 0xf, 0x0, 0x6, 0xa, 0x1, 0xd, 0x8, 0x9, 0x4, 0x5, 0xb, 0xc, 0x7, 0x2, 0xe,
],
[
0x2, 0xc, 0x4, 0x1, 0x7, 0xa, 0xb, 0x6, 0x8, 0x5, 0x3, 0xf, 0xd, 0x0, 0xe, 0x9,
0xe, 0xb, 0x2, 0xc, 0x4, 0x7, 0xd, 0x1, 0x5, 0x0, 0xf, 0xa, 0x3, 0x9, 0x8, 0x6,
0x4, 0x2, 0x1, 0xb, 0xa, 0xd, 0x7, 0x8, 0xf, 0x9, 0xc, 0x5, 0x6, 0x3, 0x0, 0xe,
0xb, 0x8, 0xc, 0x7, 0x1, 0xe, 0x2, 0xd, 0x6, 0xf, 0x0, 0x9, 0xa, 0x4, 0x5, 0x3,
],
[
0xc, 0x1, 0xa, 0xf, 0x9, 0x2, 0x6, 0x8, 0x0, 0xd, 0x3, 0x4, 0xe, 0x7, 0x5, 0xb,
0xa, 0xf, 0x4, 0x2, 0x7, 0xc, 0x9, 0x5, 0x6, 0x1, 0xd, 0xe, 0x0, 0xb, 0x3, 0x8,
0x9, 0xe, 0xf, 0x5, 0x2, 0x8, 0xc, 0x3, 0x7, 0x0, 0x4, 0xa, 0x1, 0xd, 0xb, 0x6,
0x4, 0x3, 0x2, 0xc, 0x9, 0x5, 0xf, 0xa, 0xb, 0xe, 0x1, 0x7, 0x6, 0x0, 0x8, 0xd,
],
[
0x4, 0xb, 0x2, 0xe, 0xf, 0x0, 0x8, 0xd, 0x3, 0xc, 0x9, 0x7, 0x5, 0xa, 0x6, 0x1,
0xd, 0x0, 0xb, 0x7, 0x4, 0x9, 0x1, 0xa, 0xe, 0x3, 0x5, 0xc, 0x2, 0xf, 0x8, 0x6,
0x1, 0x4, 0xb, 0xd, 0xc, 0x3, 0x7, 0xe, 0xa, 0xf, 0x6, 0x8, 0x0, 0x5, 0x9, 0x2,
0x6, 0xb, 0xd, 0x8, 0x1, 0x4, 0xa, 0x7, 0x9, 0x5, 0x0, 0xf, 0xe, 0x2, 0x3, 0xc,
],
[
0xd, 0x2, 0x8, 0x4, 0x6, 0xf, 0xb, 0x1, 0xa, 0x9, 0x3, 0xe, 0x5, 0x0, 0xc, 0x7,
0x1, 0xf, 0xd, 0x8, 0xa, 0x3, 0x7, 0x4, 0xc, 0x5, 0x6, 0xb, 0x0, 0xe, 0x9, 0x2,
0x7, 0xb, 0x4, 0x1, 0x9, 0xc, 0xe, 0x2, 0x0, 0x6, 0xa, 0xd, 0xf, 0x3, 0x5, 0x8,
0x2, 0x1, 0xe, 0x7, 0x4, 0xa, 0x8, 0xd, 0xf, 0xc, 0x9, 0x0, 0x3, 0x5, 0x6, 0xb,
],
] # 16进制表示S盒的数据，S盒是为了将48位转换为32位，有8个盒子
# 置换函数，用于密钥置换、IP置换、P置换等
def __substitution(self, table: str, self_table: list) -> str:
"""
:param table: 需要进行置换的列表,是一个01字符串
:param self_table: 置换表，在__init__中初始化了
:return: 返回置换后的01字符串
"""
sub_result = ""
for i in self_table:
sub_result += table[i - 1]
return sub_result
# 将明文转化为二进制字符串
def str2bin(self, string: str) -> str:
"""
将明文转为二进制字符串:
:param string: 任意字符串
:return:二进制字符串
"""
plaintext_list = list(bytes(string, 'utf8')) # 将字符串转成bytes类型，再转成list
result = [] # 定义返回结果
for num in plaintext_list:
result.append(bin(num)[2:].zfill(8)) # 将列表的每个元素转成二进制字符串，8位宽度；zfill(x),不足x位，左侧填充0
return "".join(result) # 连起来
# 二进制字符串转化为字符串
def bin2str(self, binary: str) -> str:
"""
二进制字符串转成字符串
:param binary:
:return:
"""
list_bin = [binary[i:i + 8] for i in range(0, len(binary), 8)] # 对二进制字符串进行切分，每8位为一组
list_int = []
for b in list_bin:
list_int.append(int(b, 2)) # 对二进制转成int
result = bytes(list_int).decode() # 将列表转成bytes，在进行解码，得到字符串
return result
# 由于加密之后的二进制无法直接转成字符，有不可见字符在，utf8可能无法解码，所以需要将二进制字符串每8位转成int型号列表，用于转成bytes再转hex
def __bin2int(self, binary: str) -> list:
"""
由于加密之后的二进制无法直接转成字符，有不可见字符在，utf8可能无法解码，所以需要将二进制字符串每8位转成int型号列表，用于转成bytes再转hex
:param binary: 二进制字符串
:return: int型列表
"""
list_bin = [binary[i:i + 8] for i in range(0, len(binary), 8)] # 对二进制字符串进行切分，每8位为一组
list_int = []
for b in list_bin:
list_int.append(int(b, 2))
return list_int
# 将int类型的列表转成二进制串
def __int2bin(self, list_int: list) -> str:
result = []
for num in list_int:
result.append(bin(num)[2:].zfill(8))
return ''.join(result)
def __get_block_list(self, binary: str) -> list:
"""
对明文二进制串进行切分，每64位为一块，DES加密以64位为一组进行加密的
:type binary: 二进制串
"""
len_binary = len(binary)
if len_binary % 64 != 0:
binary_block = binary + ("0" * (64 - (len_binary % 64)))
return [binary_block[i:i + 64] for i in range(0, len(binary_block), 64)]
else:
return [binary[j:j + 64] for j in range(0, len(binary), 64)]
# 修改默认密钥函数
def modify_secretkey(self):
"""
修改默认密钥函数
:return: None
"""
print('当前二进制形式密钥为:{}'.format(self.K))
print("当前字符串形式密钥为：{}".format(self.bin2str(self.K)))
newkey = input("输入新的密钥（长度为8）：")
if len(newkey) != 8:
print("密钥长度不符合，请重新输入：")
self.modify_secretkey()
else:
bin_key = self.str2bin(newkey)
self.K = bin_key
print("当前二进制形式密钥为:{}".format(self.K))
# F函数，right加密过程中的右半部分，key表示参与的子密钥。函数实现：对right进行E扩展，与key 进行异或操作，进入S盒替代，进行P置换，返回
def __f_funtion(self, right: str, key: str):
"""
:param right: 明文二进制的字符串加密过程的右半段
:param key: 当前轮数的密钥
:return: 进行E扩展，与key异或操作，S盒操作后返回32位01字符串
"""
# 对right进行E扩展
e_result = self.__substitution(right, self.E)
# 与key 进行异或操作
xor_result = self.__xor_function(e_result, key)
# 进入S盒子
s_result = self.__s_box(xor_result)
# 进行P置换
p_result = self.__substitution(s_result, self.P)
return p_result
# 返回加密过程中16轮的子密钥
def __get_key_list(self):
"""
:return: 返回加密过程中16轮的子密钥
"""
key = self.__substitution(self.K, self.k1)
left_key = key[0:28]
right_key = key[28:56]
keys = []
for i in range(1, 17):
move = self.k0[i - 1]
move_left = left_key[move:28] + left_key[0:move]
move_right = right_key[move:28] + right_key[0:move]
left_key = move_left
right_key = move_right
move_key = left_key + right_key
ki = self.__substitution(move_key, self.k2)
keys.append(ki)
return keys
# 异或操作返回结果
def __xor_function(self, xor1: str, xor2: str):
"""
:param xor1: 01字符串
:param xor2: 01字符串
:return: 异或操作返回的结果
"""
size = len(xor1)
result = ""
for i in range(0, size):
result += '0' if xor1[i] == xor2[i] else '1'
return result
# 进行S盒替代的函数，48位替换为32位
def __s_box(self, xor_result: str):
"""
:param xor_result: 48位01字符串
:return: 返回32位01字符串
"""
result = ""
for i in range(0, 8):
# 将48位数据分为6组，循环进行
block = xor_result[i * 6:(i + 1) * 6]
line = int(block[0] + block[5], 2)
colmn = int(block[1:4], 2)
res = bin(self.S[i][line * 16 + colmn])[2:]
if len(res) < 4:
res = '0' * (4 - len(res)) + res
result += res
return result
# 因为右半部分是操作了16轮，所以合并在一起组成一个函数，返回进行F函数以及和left异或操作之后的字符串。
def __iteration(self, bin_plaintext: str, key_list: list):
"""
:param bin_plaintext: 01字符串，64位
:param key_list: 密钥列表，共16个
:return: 进行F函数以及和left异或操作之后的字符串
"""
left = bin_plaintext[0:32]
right = bin_plaintext[32:64]
for i in range(0, 16):
next_lift = right
f_result = self.__f_funtion(right, key_list[i])
next_right = self.__xor_function(left, f_result)
left = next_lift
right = next_right
bin_plaintext_result = left + right
return bin_plaintext_result[32:] + bin_plaintext_result[:32]
def encode(self, plaintext):
"""
:param plaintext: 明文字符串
:return: 密文字符串
"""
# 将字符串变为二进制
bin_plaintext = self.str2bin(plaintext)
# 进行分组，64位一组
bin_plaintext_block = self.__get_block_list(bin_plaintext)
ciphertext_bin_list = []
# 获得子密钥
key_list = self.__get_key_list()
# 对一组明文进行加密
for block in bin_plaintext_block:
# 初代ip置换
sub_ip = self.__substitution(block, self.ip)
# 轮加密
ite_result = self.__iteration(sub_ip, key_list)
# 逆ip置换
sub_ip1 = self.__substitution(ite_result, self.ip1)
ciphertext_bin_list.append(sub_ip1)
ciphertext_bin = ''.join(ciphertext_bin_list)
result = self.__bin2int(ciphertext_bin)
return bytes(result).hex().upper()
def decode(self, ciphertext):
'''
:param ciphertext: 密文字符串
:return: 明文字符串
'''
b_ciphertext = binascii.a2b_hex(ciphertext)
bin_ciphertext = self.__int2bin(list(b_ciphertext))
bin_plaintext_list = []
key_list = self.__get_key_list()
key_list = key_list[::-1]
bin_ciphertext_block = [bin_ciphertext[i:i + 64] for i in range(0, len(bin_ciphertext), 64)]
for block in bin_ciphertext_block:
sub_ip = self.__substitution(block, self.ip)
ite = self.__iteration(sub_ip, key_list)
sub_ip1 = self.__substitution(ite, self.ip1)
bin_plaintext_list.append(sub_ip1)
bin_plaintext = ''.join(bin_plaintext_list).replace('00000000', '')
return self.bin2str(bin_plaintext)
def main(self):
select = input("Please selecting:\n1、Encryption\t 2、Decrpytion\nYour selecting:")
if select == '1':
plaintext = input("Input plaintext：")
# print("Your plaintext is:{}".format(plaintext))
ciphertext = self.encode(plaintext)
print("The ciphertext is:{}".format(ciphertext))
elif select == '2':
plaintext = input("Input ciphertext：")
# print("Your ciphertext is:{}".format(plaintext))
plaintext = self.decode(plaintext)
print("The plaintext is:{}".format(plaintext))
# print(len(plaintext))
else:
input("Please selecting again！")
self.main()
if __name__ == '__main__':
mydes = ArrangeSimpleDES()
mydes.modify_secretkey()
while True:
mydes.main()
print("")
