本文共 16270 字，大约阅读时间需要 54 分钟。
【题目】
实现 CBC 模式和 OFB 模式的 AES 算法，具体要求：
A. 实现 AES 算法的上述两种模式的加密过程，由用户输入密钥，可以对任
意输入的不小于 10M 的文本文件内容进行加密；B. 根据用户输入的密钥，对不小于 10M 的文本文件对应的密文进行解密；
【代码实现】
#!/usr/bin/env python# -*- coding:utf-8 -*- # Author: sjk# coding:utf-8import randomimport timeimport copyimport codecsclass AESE(): def __init__(self, blk, key, Nr): # 构造函数 blk:传入明文asc码列表，最大16字节，key:传入密码asc码列表，Nr:轮数 self.blk = blk # 明文列表 self.key = key # 密码列表 self.Nr = Nr self.sbox = (0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16) # xtime process def xtime(self, x): # 如果a7为1，进行亦或运算，与0x1b亦或 if (x & 0x80): return (((x << 1) ^ 0x1b) & 0xff) return x << 1 # 列混合 def MixColumns(self): tmp = [0 for t in range(4)] xt = [0 for q in range(4)] n = 0 for x in range(4): xt[0] = self.xtime(self.blk[n]) xt[1] = self.xtime(self.blk[n + 1]) xt[2] = self.xtime(self.blk[n + 2]) xt[3] = self.xtime(self.blk[n + 3]) tmp[0] = xt[0] ^ xt[1] ^ self.blk[n + 1] ^ self.blk[n + 2] ^ self.blk[n + 3] tmp[1] = self.blk[n] ^ xt[1] ^ xt[2] ^ self.blk[n + 2] ^ self.blk[n + 3] tmp[2] = self.blk[n] ^ self.blk[n + 1] ^ xt[2] ^ xt[3] ^ self.blk[n + 3] tmp[3] = xt[0] ^ self.blk[n] ^ self.blk[n + 1] ^ self.blk[n + 2] ^ xt[3] self.blk[n] = tmp[0] self.blk[n + 1] = tmp[1] self.blk[n + 2] = tmp[2] self.blk[n + 3] = tmp[3] n = n + 4 #行移位 def ShiftRows(self): # 2nd row t = self.blk[1] self.blk[1] = self.blk[5] self.blk[5] = self.blk[9] self.blk[9] = self.blk[13] self.blk[13] = t # 3nd row t = self.blk[2] self.blk[2] = self.blk[10] self.blk[10] = t t = self.blk[6] self.blk[6] = self.blk[14] self.blk[14] = t # 4nd row t = self.blk[15] self.blk[15] = self.blk[11] self.blk[11] = self.blk[7] self.blk[7] = self.blk[3] self.blk[3] = t # 字节替换 def SubBytes(self): for x in range(16): self.blk[x] = self.sbox[self.blk[x]] #轮密钥加 def AddRoundKey(self, key): x = 0 k = [0 for m in range(16)] for c in range(4): for r in range(4): k[x] = key[r][c] x = x + 1 for y in range(16): self.blk[y] ^= int(k[y]) # 打印 def show(self): for i in range(16): print(hex(self.blk[i])) # Schedule a secret key for use. #密钥扩展 def ScheduleKey(self, w, Nk): #轮常量值表 Rcon = [0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36] #w横着排 初始化初始密钥 for r in range(4): for c in range(4): w[0][r][c] = self.key[r + c * 4] #初始化剩余10轮密钥 i是轮数， j列， r是行 for i in range(1, self.Nr + 1, 1): for j in range(Nk): t = [0 for x in range(4)] for r in range(4): if j: t[r] = w[i][r][j - 1] else: t[r] = w[i - 1][r][3] if j == 0: temp = t[0] for r in range(3): t[r] = self.sbox[t[(r + 1) % 4]] t[3] = self.sbox[temp] t[0] ^= int(Rcon[i - 1]) for r in range(4): w[i][r][j] = w[i - 1][r][j] ^ t[r] # 加密函数 def AesEncrypt(self): outkey = [[[0 for col in range(4)] for row in range(4)] for s in range(11)] self.ScheduleKey(outkey, 4) self.AddRoundKey(outkey[0]) for x in range(1, self.Nr, 1): self.SubBytes() self.ShiftRows() self.MixColumns() self.AddRoundKey(outkey[x]) self.SubBytes() self.ShiftRows() self.AddRoundKey(outkey[10]) return self.blk class AESD(): def __init__(self, blk, key, Nr): self.blk = blk self.key = key self.Nr = Nr self.sbox = (0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16) def xtime(self, x): if (x & 0x80): return (((x << 1) ^ 0x1b) & 0xff) return x << 1 def ReMixColumns(self): tmp = [0 for q in range(4)] xt1 = [0 for w in range(4)] xt2 = [0 for e in range(4)] xt3 = [0 for r in range(4)] n = 0 for x in range(4): xt1[0] = self.xtime(self.blk[n]) xt1[1] = self.xtime(self.blk[n + 1]) xt1[2] = self.xtime(self.blk[n + 2]) xt1[3] = self.xtime(self.blk[n + 3]) xt2[0] = self.xtime(self.xtime(self.blk[n])) xt2[1] = self.xtime(self.xtime(self.blk[n + 1])) xt2[2] = self.xtime(self.xtime(self.blk[n + 2])) xt2[3] = self.xtime(self.xtime(self.blk[n + 3])) xt3[0] = self.xtime(self.xtime(self.xtime(self.blk[n]))) xt3[1] = self.xtime(self.xtime(self.xtime(self.blk[n + 1]))) xt3[2] = self.xtime(self.xtime(self.xtime(self.blk[n + 2]))) xt3[3] = self.xtime(self.xtime(self.xtime(self.blk[n + 3]))) tmp[0] = xt1[0] ^ xt2[0] ^ xt3[0] ^ self.blk[n + 1] ^ xt1[1] ^ xt3[1] ^ self.blk[n + 2] ^ xt2[2] ^ xt3[2] ^ \ self.blk[n + 3] ^ xt3[3] tmp[1] = self.blk[n] ^ xt3[0] ^ xt1[1] ^ xt2[1] ^ xt3[1] ^ self.blk[n + 2] ^ xt1[2] ^ xt3[2] ^ self.blk[ n + 3] ^ xt2[3] ^ xt3[3] tmp[2] = self.blk[n] ^ xt2[0] ^ xt3[0] ^ self.blk[n + 1] ^ xt3[1] ^ xt1[2] ^ xt2[2] ^ xt3[2] ^ self.blk[ n + 3] ^ xt1[3] ^ xt3[3] tmp[3] = self.blk[n] ^ xt1[0] ^ xt3[0] ^ self.blk[n + 1] ^ xt2[1] ^ xt3[1] ^ self.blk[n + 2] ^ xt3[2] ^ xt1[ 3] ^ xt2[3] ^ xt3[3] self.blk[n] = tmp[0] self.blk[n + 1] = tmp[1] self.blk[n + 2] = tmp[2] self.blk[n + 3] = tmp[3] n = n + 4 def ReShiftRows(self): # 2nd row t = self.blk[13] self.blk[13] = self.blk[9] self.blk[9] = self.blk[5] self.blk[5] = self.blk[1] self.blk[1] = t # 3rd row t = self.blk[2] self.blk[2] = self.blk[10] self.blk[10] = t t = self.blk[6] self.blk[6] = self.blk[14] self.blk[14] = t # 4th row t = self.blk[3] self.blk[3] = self.blk[7] self.blk[7] = self.blk[11] self.blk[11] = self.blk[15] self.blk[15] = t def ReSubBytes(self): for i in range(16): for j in range(256): if (self.sbox[j] == self.blk[i]): self.blk[i] = j break def AddRoundKey(self, key): x = 0 k = [0 for m in range(16)] for c in range(4): for r in range(4): k[x] = key[r][c] x = x + 1 for y in range(16): self.blk[y] ^= k[y] def ScheduleKey(self, w, Nk): Rcon = [0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36] for r in range(4): for c in range(4): w[0][r][c] = self.key[r + c * 4] for i in range(1, self.Nr + 1, 1): for j in range(Nk): t = [0 for x in range(4)] for r in range(4): if j: t[r] = w[i][r][j - 1] else: t[r] = w[i - 1][r][3] if j == 0: temp = t[0] for r in range(3): t[r] = self.sbox[t[(r + 1) % 4]] t[3] = self.sbox[temp] t[0] ^= int(Rcon[i - 1]) for r in range(4): w[i][r][j] = w[i - 1][r][j] ^ t[r] def AesDecrpyt(self, sign='ECB'): outkey = [] outkey = [[[0 for col in range(4)] for row in range(4)] for s in range(11)] # 改 self.ScheduleKey(outkey, 4) self.AddRoundKey(outkey[10]) self.ReShiftRows() self.ReSubBytes() for x in range(self.Nr - 1, 0, -1): self.AddRoundKey(outkey[x]) self.ReMixColumns() # 第二次循环出问题了 self.ReShiftRows() self.ReSubBytes() self.AddRoundKey(outkey[0]) if (sign == 'ECB'): mText = "" for x in range(16): mText += chr(self.blk[x]) return mText elif sign == 'CBC': return self.blk#把每个字符变成对应的10进制数， 返回列表def StringToListN(string): s = [0 for x in range(16)] l = len(string) for x in range(l): s[x] = int(ord(string[x])) return sdef octToHex(oct): out = [] hex_list = [hex(x) for x in oct] for i in hex_list: out.append("%02x" % int(i[2:], 16)) hex_cipher = "" for i in out: hex_cipher += i return hex_cipherdef HexToOctList(route): with codecs.open(route,'r') as f: content=f.read() octList=[] length=len(content) for i in range(0, length, 2): octList.append(int(content[i:i + 2], 16)) return octList #读取文本字符串def getPlainText(route): with codecs.open(route,'r') as f: plainText=f.read() return plainTextdef ECB(route,skey): stratTime=time.time() # --------------加密-------------------- plainText = getPlainText(route) #我加的 key = StringToListN(skey) length = len(plainText) cipher = [] if length <= 16: blk = StringToListN(plainText) a = AESE(blk, key, 10) rblk = a.AesEncrypt() cipher.extend(rblk) else: for group in range(0, length, 16): blk = StringToListN(plainText[group:group + 16]) a = AESE(blk, key, 10) cipher.extend(a.AesEncrypt()) print("16进制密文为:") hex_cipher = octToHex(cipher) print(hex_cipher) runTime=round(time.time()-stratTime,2) print("加密时长为%f s"%runTime) # ----------------------------解密------------------- stratTime = time.time() plain = "" c_length = len(cipher) if c_length <= 16: blk = cipher a = AESD(blk, key, 10) rblk = a.AesDecrpyt() plain += rblk else: for group in range(0, c_length, 16): blk = cipher[group:group + 16] # print(blk) a = AESD(blk, key, 10) rblk = a.AesDecrpyt() plain += rblk # print(plain) print("解密密文为:") print(plain) runTime = round(time.time() - stratTime, 2) print("解密时长为%f"%runTime)def CBC(route,skey): # 构造初始化向量 random.seed(time.time()) vector = [random.randint(20, 126) for y in range(16)] #16个10进制数作为初始向量 print("初始向量为:", end="------") print(vector) original_vector = copy.deepcopy(vector) #深拷贝 print("开始加密") plainText = getPlainText(route) #得到明文字符串read() stratTime = time.time() # ------------------加密-------------------- key = StringToListN(skey) #16个asccii码作为key length = len(plainText) cipher = [] xor_blk = [0 for x in range(16)] #明文长度不超过16个字符 if length <= 16: blk = StringToListN(plainText) print(blk) for i in range(16): xor_blk[i] = (blk[i] ^ vector[i]) a = AESE(xor_blk, key, 10) rblk = a.AesEncrypt() cipher.extend(rblk) else: for group in range(0, length, 16): blk = StringToListN(plainText[group:group + 16]) for i in range(16): xor_blk[i] = (blk[i] ^ vector[i]) a = AESE(xor_blk, key, 10) group_cypher = a.AesEncrypt() cipher.extend(group_cypher) vector = copy.deepcopy(group_cypher) # print(cipher) hex_cipher = octToHex(cipher) with codecs.open(r"C:\Users\HP\Desktop\aes密文.txt",'w','utf-8') as f: f.write(hex_cipher) runTime = round(time.time() - stratTime, 2) print("加密时长为%f s" % runTime) # ----------------------------解密--------------------- # print(original_vector) cipher=HexToOctList(r"C:\Users\HP\Desktop\aesCBC密文.txt") print("开始解密") stratTime = time.time() plain = "" c_length = len(cipher) # print(c_length) if c_length <= 16: blk = cipher a = AESD(blk, key, 10) rblk = a.AesDecrpyt('CBC') for i in range(16): xor_blk[i] = original_vector[i] ^ rblk[i] mText = "" for x in range(16): mText += chr(xor_blk[x]) plain += mText else: for group in range(0, c_length, 16): newblk = cipher[group:group + 16] # 原密文 # print(newblk) a = AESD(newblk, key, 10) rblk = a.AesDecrpyt('CBC') # 解密后密文 for i in range(16): xor_blk[i] = original_vector[i] ^ rblk[i] original_vector = cipher[group:group + 16] # 更新异或密文 # print(original_vector) mText = "" for x in range(16): mText += chr(xor_blk[x]) plain += mText with codecs.open(r"C:\Users\love锋\Desktop\aesCBC解密明文.txt",'w','utf-8') as f: f.write(plain) runTime = round(time.time() - stratTime, 2) print("解密时长为%f" % runTime)def OFB(route,skey): # 构造初始化向量 random.seed(time.time()) vector = [random.randint(20, 126) for y in range(16)] original_vector = copy.deepcopy(vector) print("初始向量为:", end="-----") print(vector) print("开始加密") stratTime = time.time() plainText = getPlainText(route) # -------------------------加密-------------------------- key = StringToListN(skey) length = len(plainText) cipher = [] xor_blk = [0 for x in range(16)] if length <= 16: blk = StringToListN(plainText) a = AESE(vector, key, 10) # 加密初始化向量 rblk = a.AesEncrypt() for i in range(16): xor_blk[i] = blk[i] ^ rblk[i] cipher.extend(xor_blk) else: for group in range(0, length, 16): blk = StringToListN(plainText[group:group + 16]) a = AESE(vector, key, 10) # print(vector) rblk = a.AesEncrypt() for i in range(16): xor_blk[i] = blk[i] ^ rblk[i] cipher.extend(xor_blk) # print(cipher) hex_cipher = octToHex(cipher) with codecs.open(r"C:\Users\HP\Desktop\aesOFB密文.txt",'w','utf-8') as f: f.write(hex_cipher) runTime = round(time.time() - stratTime, 2) print("加密时长为%f s" % runTime) # ------------------------解密-------------------- stratTime = time.time() plain = "" c_length = len(cipher) # print(c_length) if c_length <= 16: blk = cipher # print(original_vector) a = AESE(original_vector, key, 10) rblk = a.AesEncrypt() for i in range(16): xor_blk[i] = original_vector[i] ^ blk[i] # print(xor_blk) mText = "" for x in range(16): mText += chr(xor_blk[x]) plain += mText else: for group in range(0, c_length, 16): blk = cipher[group:group + 16] # 原密文 # print(newblk) a = AESE(original_vector, key, 10) rblk = a.AesEncrypt() # 解密后密文 for i in range(16): xor_blk[i] = rblk[i] ^ blk[i] # print(original_vector) mText = "" for x in range(16): mText += chr(xor_blk[x]) plain += mText with codecs.open(r"C:\Users\HP\Desktop\aes解密OFB明文.txt",'w','utf-8') as f: f.write(plain) runTime = round(time.time() - stratTime, 2) print("解密时长为%f" % runTime)def main(): choice = ''' 选择加密方式 (E)CB (C)BC (O)FB (Q)uit ''' while True: your_choice = input(choice).lower() if your_choice not in "ecqo": print("你的输入不符合要求，请重新输入:") continue route = input("请输入要加密的文件路径") skey = input("请输入加密秘钥") if your_choice == 'e': ECB(route,skey) elif your_choice == 'c': CBC(route,skey) elif your_choice == 'o': OFB(route,skey) elif your_choice == 'q': breakif __name__ == "__main__": main() 转载地址：http://ihaii.baihongyu.com/