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encrypt.py
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def IP_replacement(input_txt):
"""
初始置换IP
"""
ip_table = [2, 6, 3, 1, 4, 8, 5, 7]
output_txt = []
for i in range(len(ip_table)):
output_txt.append(input_txt[ip_table[i] - 1])
return output_txt
def spilt_txt(input_txt):
"""
划分左右子部分
"""
left_txt = []
right_txt = []
left_txt = input_txt[:4]
right_txt = input_txt[4:]
return left_txt, right_txt
def extended_permutation(input_txt):
"""
扩展置换
"""
ep_box = [4, 1, 2, 3, 2, 3, 4, 1]
output_txt = []
for i in range(len(ep_box)):
output_txt.append(input_txt[ep_box[i] - 1])
return output_txt
def wheel_key(input_txt, ki):
"""
加轮密钥
"""
output_txt = []
for i in range(len(input_txt)):
output_txt.append(input_txt[i] ^ ki[i])
return output_txt
def s_boxs_1(input_txt):
"""
替换盒1
"""
row = input_txt[0] << 1 | input_txt[3]
column = input_txt[1] << 1 | input_txt[2]
s_box_1 = [[1, 0, 3, 2], [3, 2, 1, 0], [0, 2, 1, 3], [3, 1, 0, 2]]
output = s_box_1[row][column]
output_txt = []
output_txt.append(output >> 1)
output_txt.append(output & 1)
return output_txt
def s_boxs_2(input_txt):
"""
替换盒2
"""
row = input_txt[0] << 1 | input_txt[3]
column = input_txt[1] << 1 | input_txt[2]
s_box_2 = [[0, 1, 2, 3], [2, 3, 1, 0], [3, 0, 1, 2], [2, 1, 0, 3]]
output = s_box_2[row][column]
output_txt = []
output_txt.append(output >> 1)
output_txt.append(output & 1)
return output_txt
def direct_replacement(input_txt):
"""
直接置换
"""
SPBox = [2, 4, 3, 1]
output_txt = []
for i in range(len(SPBox)):
output_txt.append(input_txt[SPBox[i] - 1])
return output_txt
def generation_secret_key(secret_key):
"""
子密钥生成
"""
P10 = [3, 5, 2, 7, 4, 10, 1, 9, 8, 6]
P8 = [6, 3, 7, 4, 8, 5, 10, 9]
left_shift_1 = [2, 3, 4, 5, 1]
left_shift_2 = [2, 3, 4, 5, 1]
middle_txt = []
for i in range(len(P10)):
middle_txt.append(secret_key[P10[i] - 1])
left_txt = middle_txt[:5]
right_txt = middle_txt[5:]
left_output_1 = []
right_output_1 = []
for i in range(len(left_shift_1)):
left_output_1.append(left_txt[left_shift_1[i] - 1])
for i in range(len(left_shift_1)):
right_output_1.append(right_txt[left_shift_1[i] - 1])
middle_txt.clear()
middle_txt = left_output_1 + right_output_1
k1 = []
for i in range(len(P8)):
k1.append(middle_txt[P8[i] - 1])
left_output_2 = []
right_output_2 = []
for i in range(len(left_shift_2)):
left_output_2.append(left_output_1[left_shift_2[i] - 1])
for i in range(len(left_shift_2)):
right_output_2.append(right_output_1[left_shift_2[i] - 1])
middle_txt.clear()
middle_txt = left_output_2 + right_output_2
k2 = []
for i in range(len(P8)):
k2.append(middle_txt[P8[i] - 1])
return k1, k2
def F(input_txt, k, x):
"""轮函数F"""
middle_txt = extended_permutation(input_txt)
middle_txt = wheel_key(middle_txt, k)
middle_txt_left = middle_txt[:4]
middle_txt_right = middle_txt[4:]
if x == 1:
middle_txt_left = s_boxs_1(middle_txt_left)
middle_txt_right = s_boxs_2(middle_txt_right)
else:
middle_txt_left = s_boxs_1(middle_txt_left)
middle_txt_right = s_boxs_2(middle_txt_right)
middle_txt.clear()
middle_txt = middle_txt_left + middle_txt_right
output_txt = direct_replacement(middle_txt)
return output_txt
def xor(input_txt, xor_txt):
"""异或"""
middle_txt = []
for i in range(len(input_txt)):
middle_txt.append(input_txt[i] ^ xor_txt[i])
return middle_txt
def IP_replacement_inverse(input_txt):
"""
最终置换IP
"""
ip_table = [4, 1, 3, 5, 7, 2, 8, 6]
output_txt = []
for i in range(len(ip_table)):
output_txt.append(input_txt[ip_table[i] - 1])
return output_txt
def main_encryption(plain_txt, k):
"""
加密算法
"""
middle_txt = IP_replacement(plain_txt)
left_txt, right_txt = spilt_txt(middle_txt)
k1, k2 = generation_secret_key(k)
# print(k1)
# print(k2)
xor_txt = F(right_txt, k1, 1)
left_txt = xor(left_txt, xor_txt)
left_txt, right_txt = right_txt, left_txt
xor_txt.clear()
xor_txt = F(right_txt, k2, 2)
left_txt = xor(left_txt, xor_txt)
middle_txt.clear()
middle_txt = left_txt + right_txt
cypher_txt = IP_replacement_inverse(middle_txt)
return cypher_txt
def main_decryption(cypher_txt, k):
"""
解密算法
"""
middle_txt = IP_replacement(cypher_txt)
left_txt, right_txt = spilt_txt(middle_txt)
k1, k2 = generation_secret_key(k)
xor_txt = F(right_txt, k2, 2)
left_txt = xor(left_txt, xor_txt)
left_txt, right_txt = right_txt, left_txt
xor_txt.clear()
xor_txt = F(right_txt, k1, 1)
left_txt = xor(left_txt, xor_txt)
middle_txt.clear()
middle_txt = left_txt + right_txt
plain_txt = IP_replacement_inverse(middle_txt)
return plain_txt
if __name__ == '__main__':
plain_txt = [1, 1, 1, 1, 0, 0, 0, 0]
k = [1, 1, 1, 1, 1, 0, 0, 0, 0, 0]
cypher_txt = main_encryption(plain_txt, k)
print(f'明文：{plain_txt}')
print(f'密文：{cypher_txt}')
print(f'解密：{main_decryption(cypher_txt, k)}')