集美大学计算机工程学院实验报告
课程名称：
指导教师：
实验项目名称：AES加密解密算法
实验项目编号： 班级： 姓名： 学号： 组号： 实验成绩： 上机实践日期： 上机实践时间： 2学时 一、 实验目的
学习AES加密的方法。
二、实验内容与设计思想
编写AES加密解密算法，并测试。
三、实验使用环境
操作系统： Microsoft Windows 7
编程环境：Visual C++ 6.0
四、实验步骤和调试过程
// AES.h
#ifndef AES_H_
#define AES_H_
#include <bitset>
#include <utility>
using namespace std;
class AES
{
public:
typedef unsigned char byte;
static const int KEY_SIZE = 16; //
static const int N_ROUND = 11;
byte plainText[16]; // 明文
byte state[16]; // 当前分组。
byte cipherKey[16]; // 密钥
byte roundKey[N_ROUND][16]; //轮密钥
byte cipherText[16]; //密文
byte SBox[16][16]; // S盒
byte InvSBox[16][16]; // 逆S盒
void EncryptionProcess();
void DecryptionProcess();
void Round(const int& round);
void InvRound(const int& round); 密钥长度为位
void FinalRound();
void InvFinalRound();
void KeyExpansion();
void AddRoundKey(const int& round);
void SubBytes();
void InvSubBytes();
void ShiftRows();
void InvShiftRows();
void MixColumns();
void InvMixColumns();
void BuildSBox();
void BuildInvSBox();
void InitialState(const byte* text);
void InitialCipherText();
void InitialplainText();
byte GFMultplyByte(const byte& left, const byte& right);
const byte* GFMultplyBytesMatrix(const byte* left, const byte* right); public:
AES();
const byte* Cipher(const byte* text, const byte* key, const int& keySize); const byte* InvCipher(const byte* text, const byte* key, const int& keySize); };
void AES::EncryptionProcess()
{ // 加密过程
InitialState(plainText);
KeyExpansion(); // 密钥扩展
AddRoundKey(0); // 轮密钥加
for(int i = 1; i < N_ROUND-1; ++i)
{
Round(i);
}
FinalRound();
InitialCipherText();
}
void AES::DecryptionProcess()
{ // 解密过程
InitialState(cipherText);
KeyExpansion();
InvFinalRound();
for(int i = N_ROUND-2; i > 0 ; --i)
{
InvRound(i);
}
AddRoundKey(0);
InitialplainText();
}
void AES::Round(const int& round) { // 正常轮
SubBytes();
ShiftRows();
MixColumns();
AddRoundKey(round); }
void AES::InvRound(const int& round) { // 正常轮的逆
AddRoundKey(round);
InvMixColumns();
InvShiftRows();
InvSubBytes(); }
void AES::FinalRound()
{ // 最后轮
SubBytes();
ShiftRows();
AddRoundKey(N_ROUND - 1); }
void AES::InvFinalRound()
{ // 最后轮的逆
AddRoundKey(N_ROUND - 1); InvShiftRows();
InvSubBytes();
}
void AES::KeyExpansion()
{ // 密钥扩展
const byte rcon[N_ROUND][4] = { {0x00, 0x00, 0x00, 0x00}, {0x01, 0x00, 0x00, 0x00}, {0x02, 0x00, 0x00, 0x00}, {0x04, 0x00, 0x00, 0x00}, {0x08, 0x00, 0x00, 0x00}, {0x10, 0x00, 0x00, 0x00}, {0x20, 0x00, 0x00, 0x00},
{0x40, 0x00, 0x00, 0x00},
{0x80, 0x00, 0x00, 0x00},
{0x1b, 0x00, 0x00, 0x00},
{0x36, 0x00, 0x00, 0x00} };
for(int i = 0; i < 16; ++i)
{
roundKey[0][i] = cipherKey[i];
}
for(int i = 0; i < 4; ++i)
{ // roundKey[0][16]为cipherKey的转置矩阵
for(int j = 0; j < 4; ++j)
{
roundKey[0][4*i + j] = cipherKey[4*j + i];
}
}
for(int roundIndex = 1; roundIndex < N_ROUND; ++roundIndex)
{
byte rotWord[4] = {0x00};
rotWord[0] = roundKey[roundIndex - 1][3];
rotWord[1] = roundKey[roundIndex - 1][7];
rotWord[2] = roundKey[roundIndex - 1][11];
rotWord[3] = roundKey[roundIndex - 1][15];
std::swap<byte>(rotWord[0], rotWord[1]);
std::swap<byte>(rotWord[1], rotWord[2]);
std::swap<byte>(rotWord[2], rotWord[3]);
for(int i = 0; i < 4; ++i)
{
rotWord[i] = SBox[ rotWord[i] >> 4][ rotWord[i] & 0x0f ]; roundKey[roundIndex][4*i] = roundKey[roundIndex - 1][4*i] ^ rotWord[i] ^ rcon[roundIndex][i];
}
for(int j = 1; j < 4; ++j)
{
for(int i = 0; i < 4; ++i)
{
roundKey[roundIndex][4*i + j] = roundKey[roundIndex - 1][4*i + j] ^ roundKey[roundIndex][4*i + j - 1];
}
}
}
}
void AES::AddRoundKey(const int& round)
{ // 轮密钥加
for(int i = 0; i < 16; ++i)
{ // 利用当前分组state和第round组扩展密钥进行按位异或 state[i] ^= roundKey[round][i];
}
}
void AES::SubBytes()
{ // 字节代换
for(int i = 0; i < 16; ++i)
{
state[i] = SBox[ state[i] >> 4][ state[i] & 0x0f ]; }
}
void AES::InvSubBytes()
{ // 逆字节代换
for(int i = 0; i < 16; ++i)
{
state[i] = InvSBox[ state[i] >> 4][ state[i] & 0x0f ]; }
}
void AES::ShiftRows()
{ // 行变换
//state第一行保持不变
// Do nothing.
//state第二行循环左移一个字节
std::swap<byte>(state[4], state[5]);
std::swap<byte>(state[5], state[6]);
std::swap<byte>(state[6], state[7]);
//state第三行循环左移两个字节
std::swap<byte>(state[8], state[10]);
std::swap<byte>(state[9], state[11]);
//state第三行循环左移三个字节
std::swap<byte>(state[14], state[15]);
std::swap<byte>(state[13], state[14]);
std::swap<byte>(state[12], state[13]);
}
void AES::InvShiftRows()
{ // 行变换反演
//state第一行保持不变
// Do nothing.
//state第二行循环右移一个字节
std::swap<byte>(state[6], state[7]);
std::swap<byte>(state[5], state[6]);
std::swap<byte>(state[4], state[5]);
//state第三行循环右移两个字节
std::swap<byte>(state[9], state[11]);
std::swap<byte>(state[8], state[10]);
//state第三行循环右移三个字节
std::swap<byte>(state[12], state[13]);
std::swap<byte>(state[13], state[14]);
std::swap<byte>(state[14], state[15]);
}
void AES::MixColumns()
{ // 列混淆
byte matrix[4][4] = {
{0x02, 0x03, 0x01, 0x01},
{0x01, 0x02, 0x03, 0x01},
{0x01, 0x01, 0x02, 0x03},
{0x03, 0x01, 0x01, 0x02}};
const byte* temp = GFMultplyBytesMatrix((byte*)matrix, state); for(int i = 0; i < 16; ++i)
{
state[i] = temp[i];
}
delete[] temp;
}
void AES::InvMixColumns()
{ // 列混淆反演
byte matrix[4][4] = {
{0x0e, 0x0b, 0x0d, 0x09},
{0x09, 0x0e, 0x0b, 0x0d},
{0x0d, 0x09, 0x0e, 0x0b},
{0x0b, 0x0d, 0x09, 0x0e} };
const byte* temp = GFMultplyBytesMatrix((byte*)matrix, state); for(int i = 0; i < 16; ++i)
{
state[i] = temp[i];
}
delete[] temp;
}
void AES::BuildSBox()
{ // 构建S盒
byte box[16][16] =
{
/* 0 1 2 3 4 5 6 7 8 9 a
b c d e f */
/*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},
/*a*/ {0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79},
/*b*/ {0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08},
/*c*/ {0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a},
/*d*/ {0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e},
/*e*/ {0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf},
/*f*/ {0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16}
};
for(int i = 0; i < 16; ++i)
{
for(int j = 0; j < 16; ++j)
{
SBox[i][j] = box[i][j];
}
}
}
void AES::BuildInvSBox()
{ // 构建逆S盒
byte box[16][16] =
{
/* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
/*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},
/*a*/ {0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b},
/*b*/ {0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4},
/*c*/ {0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f},
/*d*/ {0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef},
/*e*/ {0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61},
/*f*/ {0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d}
};
for(int i = 0; i < 16; ++i)
{
for(int j = 0; j < 16; ++j)
{
InvSBox[i][j] = box[i][j];
}
}
}
void AES::InitialState(const byte* text)
{ // state初始时候为明(密)文矩阵的转置矩阵
for(int i = 0; i < 4; ++i)
{ //转置text存放在state中
for(int j = 0; j < 4; ++j)
{
state[4*i + j] = text[4*j + i];
}
}
}
void AES::InitialCipherText()
{ // state被复制到输出矩阵中
for(int i = 0; i < 4; ++i)
{ //转置state存放在cipherText中
for(int j = 0; j < 4; ++j)
{
cipherText[4*i + j] = state[4*j + i];
}
}
}
void AES::InitialplainText()
{ // state被复制到输入矩阵中
for(int i = 0; i < 4; ++i)
{ //转置state存放在plainText中
for(int j = 0; j < 4; ++j)
{
plainText[4*i + j] = state[4*j + i];
}
}
}
AES::byte AES::GFMultplyByte(const byte& left, const byte& right)
{ //有限域GF(2^8)上的乘法
byte temp[8];
bitset<8> bits((unsigned long)right); //把right化为个二进制位存放在bits中 temp[0] = left;
for(int i = 1; i < 8; ++i)
{
if(temp[i-1] >= 0x80) //若(temp[i-1] 首位为"1"
{
temp[i] = temp[i-1] << 1;
temp[i] = temp[i] ^ 0x1b; //与(00011011)异或
}
else
{
temp[i] = temp[i-1] << 1;
}
}
byte result = 0x00;
for(int i = 0; i < 8; ++i)
{
if(bits[i] == 1)
{
result ^= temp[i];
}
}
return result;
}
const AES::byte* AES::GFMultplyBytesMatrix(const byte* left, const byte* right) { //有限域GF(2^8)上的矩阵(4*4)乘法
AES::byte* result = new AES::byte[16];
for(int i = 0; i < 4; ++i)
{
for(int j = 0; j < 4; ++j)
{
result[4*i + j] = GFMultplyByte(left[4*i], right[j]);
for(int k = 1; k < 4; ++k)
{
result[4*i + j] ^= GFMultplyByte(left[4*i + k], right[4*k + j]); }
}
}
return result;
}
AES::AES()
{
BuildSBox();
BuildInvSBox();
}
const AES::byte* AES::Cipher(const byte* text, const byte* key, const int& keySize)
{ // 用key给text加密
for(int i = 0; i < 16; ++i)
{
plainText[i] = text[i];
}
for(int i = 0; i < keySize; ++i)
{
cipherKey[i] = key[i];
}
EncryptionProcess();
return cipherText;
}
const AES::byte* AES::InvCipher(const byte* text, const byte* key, const int& keySize)
{ // 用key给text解密
for(int i = 0; i < 16; ++i)
{
cipherText[i] = text[i];
}
for(int i = 0; i < keySize; ++i)
{
cipherKey[i] = key[i];
}
DecryptionProcess();
return plainText;
}
#endif /* AES_H_ */
//AES.CPP
// main.cpp
#include "stdafx.h"
#include <string>
#include <fstream>
#include <iostream>
#include "AES.h"
using namespace std;
int main(int argc, char* argv[])
{
const string USAGE = "Usage: AES [-E | -D] destinationfile sourcefile keyfile ";
if(argc != 5)
{
cout << USAGE << endl;
return 1;
}
ifstream is(argv[3], ios::in | ios::binary);
if(!is)
{
cerr << "InputFileNotFoundException" << endl;
return 2;
}
ifstream ks(argv[4], ios::in | ios::binary);
if(!ks)
{
cerr << "KeyFileNotFoundException" << endl;
return 2;
}
AES aes;
const unsigned char *key = new unsigned char[16];
ks.read((char*)key, 16);
ofstream os(argv[2], ios::out | ios::binary);
if(strcmp(argv[1], "-E") == 0 || strcmp(argv[1], "-e") == 0)
{
const unsigned char* cipherText;
const unsigned char* plainText = new unsigned char[16];
while(is.read((char*)plainText, 16))
{
cipherText = aes.Cipher(plainText, key, 16);
os.write((const char*)cipherText, 16);
}
}
if(strcmp(argv[1], "-D") == 0 || strcmp(argv[1], "-d") == 0)
{
const unsigned char* plainText;
const unsigned char* cipherText = new unsigned char[16]; while(is.read((char *)cipherText, 16))
{
plainText = aes.InvCipher(cipherText, key, 16); os.write((const char*)plainText, 16);
}
delete[] cipherText;
}
delete[] key;
is.close();
ks.close();
os.close();
return 0;
}五、实验小结
六、附录
《现代密码学教程》