aes.c

AES加密算法

#include"aes.h"
#include<stdio.h>
#define LENGTH 16
#define NROWS 4
#define NCOLS 4
#define ROUNDS 12

static unsigned char  Rcon[11][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} };       // 创建轮常数表

static  unsigned char Sbox[16][16]={  // populate the Sbox matrix  建立S矩阵
		        /* 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} };       
	   //建立S-盒

static unsigned char iSbox[16][16]={  // populate the iSbox matrix
		       /* 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} };
		 // BuildInvSbox()

	static unsigned char w[52][4],State[4][4];
	//int m,n;

 void SubWord(unsigned char* temp)//用一个代替表 替换单个字节
{
	temp[0] =  Sbox[ temp[0] >> 4][ temp[0] & 0x0f ];
	temp[1] =  Sbox[ temp[1] >> 4][ temp[1] & 0x0f ];
	temp[2] =  Sbox[ temp[2] >> 4][ temp[2] & 0x0f ];
	temp[3] =  Sbox[ temp[3] >> 4][ temp[3] & 0x0f ];
}//被代替的输入字节被分成 (x,y) 对，它被当作进入替换表 Sbox 的索引。例如0x27的代替结果是 x＝2 和 y＝7，并且 Sbox[2,7] 返回 0xcc。



 void  RotWord(unsigned char* temp)//接受一个4个字节的数组并将它们向左旋转一个位置
{
	unsigned char t;
	t=temp[0];
	temp[0]=temp[1];
	temp[1]=temp[2];
	temp[2]=temp[3];
	temp[3]=t;
}



void KeyExpansion(unsigned char* key)   //密钥扩展
{
	unsigned char temp[4];  
    int row;
	for (row = 0; row < 6; ++row)
	{
         w[row][0]=key[4*row];
         w[row][1]=key[4*row+1];
         w[row][2]=key[4*row+2];
         w[row][3]=key[4*row+3];
	}
	for (row =6; row < 52; ++row)
	{
        temp[0]=w[row-1][0];   temp[1]=w[row-1][1];
        temp[2]=w[row-1][2];   temp[3]=w[row-1][3];
		
        if (row % 6 == 0)  
        {
			RotWord(temp);
			SubWord(temp);
			temp[0] = (unsigned char)( (int)temp[0] ^ (int) Rcon[row/6][0] );
			temp[1] = (unsigned char)( (int)temp[1] ^ (int) Rcon[row/6][1] );
			temp[2] = (unsigned char)( (int)temp[2] ^ (int) Rcon[row/6][2] );
			temp[3] = (unsigned char)( (int)temp[3] ^ (int) Rcon[row/6][3] );
        }
         w[row][0] = (unsigned char) ( (int) w[row-6][0] ^ (int)temp[0] );
         w[row][1] = (unsigned char) ( (int) w[row-6][1] ^ (int)temp[1] );
         w[row][2] = (unsigned char) ( (int) w[row-6][2] ^ (int)temp[2] );
         w[row][3] = (unsigned char) ( (int) w[row-6][3] ^ (int)temp[3] );
		
	}  // for loop
	//return w;
}  // KeyExpansion()




void AddRoundKey(int round)
{
	int r,c;
	for ( r = 0; r < 4; ++r)
	{
        for ( c = 0; c < 4; ++c)
        {
			 State[r][c] = (unsigned char) ( (int) State[r][c] ^ (int)w[(round*4)+c][r] );
        }
	}
}  // AddRoundKey()


void SubBytes()
{
	int r,c;
	for (r = 0; r < 4; ++r)
	{
        for (c = 0; c < 4; ++c)
        {
			 State[r][c] =  Sbox[ ( State[r][c] >> 4)][( State[r][c] & 0x0f) ];
        }
	}
}  // SubBytes
/*将 State 矩阵中的每个字节替换成一个由 Sbox 决定的新字节,
  比如，如果 State[0,1]的值是 0x40 如果你想找到它的代替者,
  你取 State[0,1] 的值 (0x40) 并让 x 等于左边的数字(4)并让 y 等于右边的数字(0),
  然后你用 x 和 y 作为索引 进到 Sbox 表中寻找代替值*/

void InvSubBytes()
{
	int r,c;
	for (r = 0; r < 4; ++r)
	{
        for (c = 0; c < 4; ++c)
        {
			 State[r][c] =  iSbox[ ( State[r][c] >> 4)][( State[r][c] & 0x0f) ];
        }
	}
}  // InvSubBytes


void ShiftRows()
{
 unsigned char temp[4][4];
	int r,c;
	memcpy(temp,State, 16);
	/*for ( r = 0; r < 4; ++r)  // copy State into temp[]
	{
        for ( c = 0; c < 4; ++c)
        {
			temp[r][c] =  State[r][c];
        }
	}*/
	
	for (r = 1; r < 4; ++r)  // shift temp into State
	{
        for (c = 0; c < 4; ++c)
        {
			 State[r][c] = temp[ r][(c + r) % 4 ];
        }
	}
}  // ShiftRows()
/*将 State 矩阵中的字节向左旋转
State 的第0行被向左旋转0个位置，State 的第1行被向左旋转1个位置，
State 的第2行被向左旋转2个位置，而 State 的第3行被向左旋转3个 位置。*/


void InvShiftRows()
{
	unsigned char temp[4][4];
	int r,c;
	memcpy(temp,State, 16);
	/*for ( r = 0; r < 4; ++r)  // copy State into temp[]
	{
        for ( c = 0; c < 4; ++c)
        {
			temp[r][c] =  State[r][c];
        }
	}*/
	
	for (r = 1; r < 4; ++r)  // shift temp into State
	{
        for (c = 0; c < 4; ++c)
        {
			 State[ r][(c + r) % 4 ] = temp[r][c];
        }
	}
}  // InvShiftRows()



unsigned char gfmultby01(unsigned char b)
{
	return b;
}                        //有限域GF(28)0x01的乘法

unsigned char gfmultby02(unsigned char b)
{
	if (b < 0x80)
        return (unsigned char)(int)(b <<1);
	else
		return (unsigned char)( (int)(b << 1) ^ (int)(0x1b) );
}                                                    //有限域GF(28)0x02的乘法

unsigned char gfmultby03(unsigned char b)
{
	return (unsigned char) ( (int)gfmultby02(b) ^ (int)b );
}                                                     //有限域GF(28)0x03的乘法

unsigned char gfmultby09(unsigned char b)
{
	return (unsigned char)( (int)gfmultby02(gfmultby02(gfmultby02(b))) ^
		(int)b );
}                                                        //有限域GF(28)0x09的乘法

unsigned char gfmultby0b(unsigned char b)
{
	return (unsigned char)( (int)gfmultby02(gfmultby02(gfmultby02(b))) ^
		(int)gfmultby02(b) ^
		(int)b );
}                                                         //有限域GF(28)0x0b的乘法

unsigned char gfmultby0d(unsigned char b)
{
	return (unsigned char)( (int)gfmultby02(gfmultby02(gfmultby02(b))) ^
		(int)gfmultby02(gfmultby02(b)) ^
		(int)(b) );
}                                                         //有限域GF(28)0x0d的乘法                 

unsigned char gfmultby0e(unsigned char b)
{
	return (unsigned char)( (int)gfmultby02(gfmultby02(gfmultby02(b))) ^
		(int)gfmultby02(gfmultby02(b)) ^
		(int)gfmultby02(b) );
}                                                          //有限域GF(28)0x0e的乘法




void MixColumns()
{
	unsigned char temp[4][4];
	int c;
	memcpy(temp,State, 16);
	/*for ( r = 0; r < 4; ++r)  // copy State into temp[]
	{
        for (c = 0; c < 4; ++c)
        {
			temp[r][c] =  State[r][c];
        }
	}*/
	
	for (c = 0; c < 4; ++c)
	{
		 State[0][c] = (unsigned char) ( (int)gfmultby02(temp[0][c]) ^ (int)gfmultby03(temp[1][c]) ^
			(int)gfmultby01(temp[2][c]) ^ (int)gfmultby01(temp[3][c]) );
         State[1][c] = (unsigned char) ( (int)gfmultby01(temp[0][c]) ^ (int)gfmultby02(temp[1][c]) ^
			(int)gfmultby03(temp[2][c]) ^ (int)gfmultby01(temp[3][c]) );
         State[2][c] = (unsigned char) ( (int)gfmultby01(temp[0][c]) ^ (int)gfmultby01(temp[1][c]) ^
			(int)gfmultby02(temp[2][c]) ^ (int)gfmultby03(temp[3][c]) );
         State[3][c] = (unsigned char) ( (int)gfmultby03(temp[0][c]) ^ (int)gfmultby01(temp[1][c]) ^
			(int)gfmultby01(temp[2][c]) ^ (int)gfmultby02(temp[3][c]) );
	}
}  // MixColumns 用 State 字节列的值进行数学域加和域乘的结果代替每个字节



void InvMixColumns()
{
	unsigned char temp[4][4];
	int c;
	memcpy(temp,State, 16);
	/*for ( r = 0; r < 4; ++r)  // copy State into temp[]
	{
        for (c = 0; c < 4; ++c)
        {
			temp[r][c] =  State[r][c];
        }
	}*/
	

	for (c = 0; c < 4; ++c)
	{
         State[0][c] = (unsigned char) ( (int)gfmultby0e(temp[0][c]) ^ (int)gfmultby0b(temp[1][c]) ^
			(int)gfmultby0d(temp[2][c]) ^ (int)gfmultby09(temp[3][c]) );
         State[1][c] = (unsigned char) ( (int)gfmultby09(temp[0][c]) ^ (int)gfmultby0e(temp[1][c]) ^
			(int)gfmultby0b(temp[2][c]) ^ (int)gfmultby0d(temp[3][c]) );
         State[2][c] = (unsigned char) ( (int)gfmultby0d(temp[0][c]) ^ (int)gfmultby09(temp[1][c]) ^
			(int)gfmultby0e(temp[2][c]) ^ (int)gfmultby0b(temp[3][c]) );
         State[3][c] = (unsigned char) ( (int)gfmultby0b(temp[0][c]) ^ (int)gfmultby0d(temp[1][c]) ^
			(int)gfmultby09(temp[2][c]) ^ (int)gfmultby0e(temp[3][c]) );
	}
}  // InvMixColumns



void cipher(unsigned char plaintext[LENGTH],unsigned char key[LENGTH])
/*plaintext是16字节的明文，ciphertext是16字节的密文，key是16字节的密钥*/
{
	int r;                           //loop index循环次数        
	//State （态）的 4×4 字节矩阵，拷贝 16 字节的明文到State中 
	//struct{byte k[NROWS][NROWS];}rk[ROUNDS+1];  //状态数组
	
	KeyExpansion(key);
	memcpy(State, plaintext, 16);    //state数组首先初始化为明文数据
	AddRoundKey(0);
	//xor_roundkey_into_state(state,rk[0]);
    
	for(r=1;r<=(ROUNDS-1);++r)
	{
		SubBytes(); 
        ShiftRows();  
        MixColumns(); 
        AddRoundKey(r);
	}     // main round loop
	SubBytes();
	ShiftRows();
	AddRoundKey(ROUNDS);
	memcpy(plaintext,State, 16);
	//copy_plaintext_to_state(state,plaintext);
}


void Invcipher(unsigned char plaintext[LENGTH],unsigned char key[LENGTH])  // decipher 16-bit input
{
	int r;
	memcpy(State, plaintext, 16); 
	
	AddRoundKey(ROUNDS);
	
	for (r=ROUNDS-1; r >= 1; --r)  // main round loop
	{
        InvShiftRows();
        InvSubBytes();
        AddRoundKey(r);
        InvMixColumns();
	}  // end main round loop for InvCipher
	
	InvShiftRows();
	InvSubBytes();
	AddRoundKey(0);	
	// output = state
	memcpy(plaintext,State, 16);
	
}  // InvCipher()

void cipher_Go(unsigned char plaintext[LENGTH],long datalen,unsigned char key[LENGTH])
{
	int i,j;
	for(i=0,j=datalen>>6; i<j; ++i,plaintext+=16)
		cipher(plaintext,key);
}


void Invcipher_Go(unsigned char plaintext[LENGTH],long datalen,unsigned char key[LENGTH])
{
	int i,j;
	for(i=0,j=datalen>>6; i<j; ++i,plaintext+=16)
		Invcipher(plaintext,key);
}