Python实现AES算法
密码学课程老师留的作业，我觉得用python实现更简单，就用python写了一个加解密的程序。
程序分成三个部分，一个部分是生成轮密钥，一个加密，一个是解密。
生成轮密钥
这个部分要看是不是四的倍数，非四的倍数是简单的，直接异或就可以了。如果是4的倍数，这时就需要执行字节代替和异或运算。
for i in range(4):#把16进制转成十进制
for j in range(0, 8, 2 ):
self.subkey[i].append('0x'+key[i*8+j:i*8+j+2])
for i in range(4,44):#生成密钥
if i%4 !=0:
tmp = xor_32(self.subkey[i-1], self.subkey[i-4])
self.subkey.append(tmp)
else:#4的倍数的时候执行
tmp1 = self.subkey[i-1][1:]
tmp1.append(self.subkey[i-1][0])
tmp1 = self.S_box(tmp1) #字节代替
tmp1 = xor_32(tmp1,self.Rcon[i/4])#和Rcon异或
self.subkey.append(xor_32(tmp1,self.subkey[i-4]))
加密
加密时最难实现的是列混淆，因为要实现域上的乘法，没想到用递归实现的好方法，还是把一个一个用if判断来进行运算。
解密
解密的时候最难的仍然是逆列混淆运算，仍然是最傻的if判断。
完整代码如下
# -*- coding: utf-8 -*-
"""
Created on Fri Nov 1 18:47:24 2019
@author: pkill
"""
class AesCryption:
s_box = { #字节替换s盒
0:['0x63', '0x7c', '0x77', '0x7b', '0xf2', '0x6b', '0x6f', '0xc5', '0x30', '0x01', '0x67', '0x2b',
'0xfe', '0xd7', '0xab', '0x76'],
1:['0xca', '0x82', '0xc9', '0x7d', '0xfa', '0x59', '0x47', '0xf0', '0xad', '0xd4', '0xa2', '0xaf', '0x9c', '0xa4', '0x72', '0xc0'],
2:['0xb7', '0xfd', '0x93', '0x26', '0x36', '0x3f', '0xf7', '0xcc', '0x34', '0xa5', '0xe5', '0xf1', '0x71', '0xd8', '0x31', '0x15'],
3:['0x04', '0xc7', '0x23', '0xc3', '0x18', '0x96', '0x05', '0x9a', '0x07', '0x12', '0x80', '0xe2', '0xeb', '0x27', '0xb2', '0x75'],
4:['0x09', '0x83', '0x2c', '0x1a', '0x1b', '0x6e', '0x5a', '0xa0', '0x52', '0x3b', '0xd6', '0xb3', '0x29', '0xe3', '0x2f', '0x84'],
5:['0x53', '0xd1', '0x00', '0xed', '0x20', '0xfc', '0xb1', '0x5b', '0x6a', '0xcb', '0xbe', '0x39', '0x4a', '0x4c', '0x58', '0xcf'],
6:['0xd0', '0xef', '0xaa', '0xfb', '0x43', '0x4d', '0x33', '0x85', '0x45', '0xf9', '0x02', '0x7f',
'0x50', '0x3c', '0x9f', '0xa8'],
7:['0x51', '0xa3', '0x40', '0x8f', '0x92', '0x9d', '0x38', '0xf5', '0xbc', '0xb6', '0xda', '0x21',
'0x10', '0xff', '0xf3', '0xd2'],
8:['0xcd', '0x0c', '0x13', '0xec', '0x5f', '0x97', '0x44', '0x17', '0xc4', '0xa7', '0x7e', '0x3d',
'0x64', '0x5d', '0x19', '0x73'],
9:['0x60', '0x81', '0x4f', '0xdc', '0x22', '0x2a', '0x90', '0x88', '0x46', '0xee', '0xb8', '0x14',
'0xde', '0x5e', '0x0b', '0xdb'],
10:['0xe0', '0x32', '0x3a', '0x0a', '0x49', '0x06', '0x24', '0x5c', '0xc2', '0xd3', '0xac', '0x62', '0x91', '0x95', '0xe4', '0x79'],
11:['0xe7', '0xc8', '0x37', '0x6d', '0x8d', '0xd5', '0x4e', '0xa9', '0x6c', '0x56', '0xf4', '0xea', '0x65', '0x7a', '0xae', '0x08'],
12:['0xba', '0x78', '0x25', '0x2e', '0x1c', '0xa6', '0xb4', '0xc6', '0xe8', '0xdd', '0x74', '0x1f', '0x4b', '0xbd', '0x8b', '0x8a'],
13:['0x70', '0x3e', '0xb5', '0x66', '0x48', '0x03', '0xf6', '0x0e', '0x61', '0x35', '0x57', '0xb9', '0x86', '0xc1', '0x1d', '0x9e'],
14:['0xe1', '0xf8', '0x98', '0x11', '0x69', '0xd9', '0x8e', '0x94', '0x9b', '0x1e', '0x87', '0xe9', '0xce', '0x55', '0x28', '0xdf'],
15:['0x8c', '0xa1', '0x89', '0x0d', '0xbf', '0xe6', '0x42', '0x68', '0x41', '0x99', '0x2d', '0x0f', '0xb0', '0x54', '0xbb', '0x16']
}
s_1_box = { #逆字节替换s盒
0:['0x52', '0x09', '0x6a', '0xd5', '0x30', '0x36', '0xa5', '0x38', '0xbf', '0x40', '0xa3', '0x9e', '0x81', '0xf3', '0xd7', '0xfb'],
1:['0x7c', '0xe3', '0x39', '0x82', '0x9b', '0x2f', '0xff', '0x87', '0x34', '0x8e', '0x43', '0x44', '0xc4', '0xde', '0xe9', '0xcb'],
2:['0x54', '0x7b', '0x94', '0x32', '0xa6', '0xc2', '0x23', '0x3d', '0xee', '0x4c', '0x95', '0x0b', '0x42', '0xfa', '0xc3', '0x4e'],
3:['0x08', '0x2e', '0xa1', '0x66', '0x28', '0xd9', '0x24', '0xb2', '0x76', '0x5b', '0xa2', '0x49', '0x6d', '0x8b', '0xd1', '0x25'],
4:['0x72', '0xf8', '0xf6', '0x64', '0x86', '0x68', '0x98', '0x16', '0xd4', '0xa4', '0x5c', '0xcc', '0x5d', '0x65', '0xb6', '0x92'],
5:['0x6c', '0x70', '0x48', '0x50', '0xfd', '0xed', '0xb9', '0xda', '0x5e', '0x15', '0x46', '0x57', '0xa7', '0x8d', '0x9d', '0x84'],
6:['0x90', '0xd8', '0xab', '0x00', '0x8c', '0xbc', '0xd3', '0x0a', '0xf7', '0xe4', '0x58', '0x05', '0xb8', '0xb3', '0x45', '0x06'],
7:['0xd0', '0x2c', '0x1e', '0x8f', '0xca', '0x3f', '0x0f', '0x02', '0xc1', '0xaf', '0xbd', '0x03', '0x01', '0x13', '0x8a', '0x6b'],
8:['0x3a', '0x91', '0x11', '0x41', '0x4f', '0x67', '0xdc', '0xea', '0x97', '0xf2', '0xcf', '0xce', '0xf0', '0xb4', '0xe6', '0x73'],
9:['0x96', '0xac', '0x74', '0x22', '0xe7', '0xad', '0x35', '0x85', '0xe2', '0xf9', '0x37', '0xe8', '0x1c', '0x75', '0xdf', '0x6e'],
10:['0x47', '0xf1', '0x1a', '0x71', '0x1d', '0x29', '0xc5', '0x89', '0x6f', '0xb7', '0x62', '0x0e', '0xaa', '0x18', '0xbe', '0x1b'],
11:['0xfc', '0x56', '0x3e', '0x4b', '0xc6', '0xd2', '0x79', '0x20', '0x9a', '0xdb', '0xc0', '0xfe', '0x78', '0xcd', '0x5a', '0xf4'],
12:['0x1f', '0xdd', '0xa8', '0x33', '0x88', '0x07', '0xc7', '0x31', '0xb1', '0x12', '0x10', '0x59', '0x27', '0x80', '0xec', '0x5f'],
13:['0x60', '0x51', '0x7f', '0xa9', '0x19', '0xb5', '0x4a', '0x0d', '0x2d', '0xe5', '0x7a', '0x9f', '0x93', '0xc9', '0x9c', '0xef'],
14:['0xa0', '0xe0', '0x3b', '0x4d', '0xae', '0x2a', '0xf5', '0xb0', '0xc8', '0xeb', '0xbb', '0x3c', '0x83', '0x53', '0x99', '0x61'],
15:['0x17', '0x2b', '0x04', '0x7e', '0xba', '0x77', '0xd6', '0x26', '0xe1', '0x69', '0x14', '0x63', '0x55', '0x21', '0x0c', '0x7d']
}
Rcon = { #Rcon生成密钥的表
1: ['0x01','0x00', '0x00', '0x00'],
2: ['0x02', '0x00', '0x00', '0x00'],
3: ['0x04', '0x00', '0x00', '0x00'],
4: ['0x08', '0x00', '0x00', '0x00'],
5: ['0x10', '0x00', '0x00', '0x00'],
6: ['0x20', '0x00', '0x00', '0x00'],
7: ['0x40', '0x00', '0x00', '0x00'],
8: ['0x80', '0x00', '0x00', '0x00'],
9: ['0x1B', '0x00', '0x00', '0x00'],
10: ['0x36', '0x00', '0x00', '0x00']
}
Matrix = [ #列混淆
['0x02','0x03','0x01','0x01'],
['0x01','0x02','0x03','0x01'],
['0x01','0x01','0x02','0x03'],
['0x03','0x01','0x01','0x02']
]
InvMatrix = [ #逆列混淆
['0x0e','0x0b','0x0d','0x09'],
['0x09','0x0e','0x0b','0x0d'],
['0x0d','0x09','0x0e','0x0b'],
['0x0b','0x0d','0x09','0x0e']
]
plaintext = [[],[],[],[]] #存放明文
plaintext1 = [[],[],[],[]]
subkey = [[],[],[],[]] #存放密钥
def __init__(self,key):#构造函数，同时生成密钥
for i in range(4):#把16进制转成十进制
for j in range(0, 8, 2 ):
self.subkey[i].append('0x'+key[i*8+j:i*8+j+2])
for i in range(4,44):#生成密钥
if i%4 !=0:
tmp = xor_32(self.subkey[i-1], self.subkey[i-4])
self.subkey.append(tmp)
else:#4的倍数的时候执行
tmp1 = self.subkey[i-1][1:]
tmp1.append(self.subkey[i-1][0])
tmp1 = self.S_box(tmp1) #字节代替
tmp1 = xor_32(tmp1,self.Rcon[i/4])#和Rcon异或
self.subkey.append(xor_32(tmp1,self.subkey[i-4]))
def AddRoundKey(self,round):#轮密钥加函数
for i in range(4):
self.plaintext[i] = xor_32(self.plaintext[i],self.subkey[round*4+i])
def PlainSubBytes(self):#明文字节代替函数
for i in range(4):
self.plaintext[i] = self.S_box(self.plaintext[i])
def ShiftRows(self):#移位函数
p1,p2,p3,p4 = self.plaintext[0][1],self.plaintext[1][1],self.plaintext[2][1],self.plaintext[3][1]
self.plaintext[0][1] = p2;self.plaintext[1][1] = p3;self.plaintext[2][1] = p4;self.plaintext[3][1] = p1
p1,p2,p3,p4 = self.plaintext[0][2],self.plaintext[1][2],self.plaintext[2][2],self.plaintext[3][2]
self.plaintext[0][2] = p3;self.plaintext[1][2] = p4;self.plaintext[2][2] = p1;self.plaintext[3][2] = p2
p1,p2,p3,p4 = self.plaintext[0][3],self.plaintext[1][3],self.plaintext[2][3],self.plaintext[3][3]
self.plaintext[0][3] = p4;self.plaintext[1][3] = p1;self.plaintext[2][3] = p2;self.plaintext[3][3] = p3
def S_box(self,row):#s盒函数
a = []
for i in range(4):
a.append(self.s_box[int(row[i][2],16)][int(row[i][3],16)])
return a
def S_1_box(self,row):#逆s盒函数
a = []
for i in range(4):
a.append(self.s_1_box[int(row[i][2],16)][int(row[i][3],16)])
return a
def MixColumns(self):#列混淆函数
for i in range(4):
for j in range(4):
self.plaintext1[i].append(mc(self.Matrix[j],self.plaintext[i]))
def InvShiftRows(self):#逆移位函数
p1,p2,p3,p4 = self.plaintext[0][1],self.plaintext[1][1],self.plaintext[2][1],self.plaintext[3][1]
self.plaintext[3][1] = p3;self.plaintext[2][1] = p2;self.plaintext[0][1] = p4;self.plaintext[1][1] = p1
p1,p2,p3,p4 = self.plaintext[0][2],self.plaintext[1][2],self.plaintext[2][2],self.plaintext[3][2]
self.plaintext[0][2] = p3;self.plaintext[1][2] = p4;self.plaintext[2][2] = p1;self.plaintext[3][2] = p2
p1,p2,p3,p4 = self.plaintext[0][3],self.plaintext[1][3],self.plaintext[2][3],self.plaintext[3][3]
self.plaintext[0][3] = p2;self.plaintext[1][3] = p3;self.plaintext[2][3] = p4;self.plaintext[3][3] = p1
def InvSubBytes(self):#逆字节代替
for i in range(4):
self.plaintext[i] = self.S_1_box(self.plaintext[i])
def InvMixColumns(self):#逆列混淆
for i in range(4):
for j in range(4):
self.plaintext1[i].append(mc(self.InvMatrix[j],self.plaintext[i]))
def AesEncrypt(self,plain):#加密函数
for i in range(4):
for j in range(0, 8, 2 ):
self.plaintext[i].append('0x'+plain[i*8+j:i*8+j+2])#把16进制转化成二进制
self.AddRoundKey(0)#第一轮密钥加
for i in range(9):
self.PlainSubBytes()#字节代替
self.ShiftRows()#行移位
self.MixColumns()#列混淆
self.plaintext = self.plaintext1#把列混淆生成的密钥赋值给plaintext
self.plaintext1 = [[],[],[],[]]#重置
self.AddRoundKey(i+1)
self.PlainSubBytes()#最后一轮字节代替
self.ShiftRows()#最后一轮行移位
self.AddRoundKey(10)#最后一轮轮密钥加
return Matrixtostr(self.plaintext)#把二进制转换成诗十六进制
def AesDecrypt(self,cipher):
for i in range(4):
for j in range(0, 8, 2 ):
self.plaintext[i].append('0x'+cipher[i*8+j:i*8+j+2])#16进制转成2进制
self.AddRoundKey(10)#轮密钥加
for i in range(9):
self.InvShiftRows()#逆行移位
self.InvSubBytes()#逆字节代替
self.AddRoundKey(9-i)#轮密钥加
self.InvMixColumns()#逆列混淆
self.plaintext = self.plaintext1
self.plaintext1 = [[],[],[],[]]
self.InvShiftRows()
self.InvSubBytes()
self.AddRoundKey(0)
return Matrixtostr(self.plaintext)#把二进制转换成十六进制
def hextobin(word):#把十六进制转换成二进制
word = bin(int(word,16))[2:]
for i in range(0,8-len(word)):#补全八位
word = '0'+word
return word
def bintohex(word):#把二进制转换十六进制
word = hex(int(word, 2))
if len(word) == 4:
return word
elif len(word) <4:
return word.replace('x','x0')#0x5-->0x05
def xor_32(start, end):#32位进行异或
a = []
for i in range(0,4):
xor_tmp = ""
b = hextobin(start[i])
c = hextobin(end[i])
for j in range(8):
xor_tmp += str(int(b[j],10)^int(c[j],10))
a.append(bintohex(xor_tmp))
return a
def xor_8(begin, end):#8位异或
xor_8_tmp = ""
for i in range(8):
xor_8_tmp += str(int(begin[i])^int(end[i]))
return xor_8_tmp
def Fa(a,b):#列混淆中的乘法运算
if a == 1:
return b
elif a == 2:
if b[0] == '0':
b = b[1:] + '0'
else:
b = b[1:] + '0'
b = xor_8(b,'00011011')
return b
elif a == 3:
tmp_b = b
if b[0] == '0':
b = b[1:] + '0'
else:
b = b[1:] + '0'
b = xor_8(b,'00011011')
return xor_8(b,tmp_b)
elif a == 9:
tmp_b = b
return xor_8(tmp_b,Fa(2,Fa(2,Fa(2,b))))
elif a == 11:
tmp_b = b
return xor_8(tmp_b, xor_8(Fa(2,Fa(2,Fa(2,b))),Fa(2,b)))
elif a == 13:
tmp_b = b
return xor_8(tmp_b, xor_8(Fa(2,Fa(2,Fa(2,b))),Fa(2,Fa(2,b))))
elif a == 14:
return xor_8(Fa(2,b), xor_8(Fa(2,Fa(2,Fa(2,b))),Fa(2,Fa(2,b))))
def mc(s1,s2):#列混淆中的矩阵乘法
result = []
s3 = []
for i in range(4):
s3.append(hextobin(s2[i]))
for i in range(4):
result.append(Fa(int(s1[i],16),s3[i]))
for i in range(3):
result[0] = xor_8(result[0],result[i+1])
return bintohex(result[0])
def Matrixtostr(matrix):#矩阵转成字符串
result = ""
for i in range(4):
for j in range(4):
result += matrix[i][j][2:]
return result
测试
输入和输出都是16进制格式的字符串：
测试例子：
key = 2b7e151628aed2a6abf7158809cf4f3c
plain = 3243f6a8885a308d313198a2e0370734
cipher = 3925841d02dc09fbdc118597196a0b32
测试程序
# -*- coding: utf-8 -*-
"""
Created on Fri Nov 1 19:37:00 2019
@author: whoami
"""
from AesCryption import AesCryption
key = input("key = ")
plain = input("plain = ")
cipher = input("cipher = ")
aesencrypt = AesCryption(key)
print('密文是：'+aesencrypt.AesEncrypt(plain))
print()
print('明文是：'+aesencrypt.AesDecrypt(cipher))
Python实现AES-CFB8加解密
import json
from base64 import b64encode, b64decode
from Crypto.Cipher import AES
from Crypto.Random import get_random_bytes
def cfb_encrypt(data, key, iv=None):
if iv is None:
iv = get_random_bytes(16)
cipher = AES.new(key, AES.MODE_CFB, iv, segment_size=8)
ct_bytes = cipher.encrypt(data)
ct = b64encode(ct_bytes).decode('utf-8')
iv = b64encode(iv).decode('utf-8')
return encrypt_data, iv
def cfb8_decrypt(ciphertext, iv, key):
iv = b64decode(iv)
ct = b64decode(ciphertext)
cipher = AES.new(key, AES.MODE_CFB, iv, segment_size=8)
decrypt_data = cipher.decrypt(ct)
return decrypt_data
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