实验要求：编写DES算法实现程序，运行DES程序，演示DES加密与解密的过程。在加密时显示明文和密钥，在加密过程中在每一轮执行完毕后显示该轮的输出。
（话不多说，直接上代码！！！）
实验代码：
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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，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
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
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
return "".join(result)
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
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
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)]
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))
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
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
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
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
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
"""
bin_plaintext = self.str2bin(plaintext)
bin_plaintext_block = self.__get_block_list(bin_plaintext)
ciphertext_bin_list = []
key_list = self.__get_key_list()
counter = 1
for i in key_list:
print(f"第{counter}轮子密钥是：{i}")
counter += 1
for block in bin_plaintext_block:
# 初代ip置换
sub_ip = self.__substitution(block, self.ip)
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)
counter = 1
for i in result:
print(f"第{counter}轮加密结果为：{i}")
counter += 1
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]
counter = 1
for i in key_list:
print(f"第{counter}轮子密钥是：{i}")
counter += 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)
result = self.__bin2int(bin_plaintext)
counter = 1
for i in result:
print(f"第{counter}轮解密结果为：{i}")
counter += 1
bin_plaintext = ''.join(bin_plaintext_list).replace('00000000', '')
return self.bin2str(bin_plaintext)
def main(self):
select = input("请选择:\n1、加密\t 2、解密\n请你选择1或2:")
if select == '1':
plaintext = input("明文：")
ciphertext = self.encode(plaintext)
print("密文:{}".format(ciphertext))
elif select == '2':
plaintext = input("密文：")
plaintext = self.decode(plaintext)
print("明文:{}".format(plaintext))
else:
input("请重新选择！")
self.main()
if __name__ == '__main__':
mydes = ArrangeSimpleDES()
mydes.modify_secretkey()
while True:
mydes.main()
print("")
运行结果：
加密过程
解密过程
解析：
其中，子密钥生成操作如下：
用流程图表示为（手写版见谅啦~）
加密操作过程如下：
用流程图表示为（手写版嘿嘿有点丑就是说。。。）
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