aes.c

加减密

/*													
	Cryptosystem for 128 bits plaintext block.
*/
#include "StdAfx.h"
#include "stdio.h" 

typedef unsigned char  u1byte;
typedef unsigned long  u4byte;
 
#define LARGE_TABLE		0
 
u1byte pow_tab[256];
u1byte log_tab[256];
u1byte sbx_tab[256];
u1byte isb_tab[256];
u4byte rco_tab[10];
u4byte ft_tab[4][256];
u4byte it_tab[4][256];
 
#ifdef LARGE_TABLE
	u4byte fl_tab[4][256];
	u4byte il_tab[4][256];
#endif
 
u4byte tab_gen=0;
 
u4byte k_len;
u4byte e_key[60];
u4byte d_key[60];
 
#define ff_mult(a,b) (a && b ? pow_tab[(log_tab[a]+log_tab[b])%255]:0)
 
#define byte(x,n) ((u1byte)((x)>>(8*n)))
 
#define f_rn(bo,bi,n,k)             \
	bo[n]=ft_tab[0][byte(bi[n],0)]^   \
	ft_tab[1][byte(bi[(n+1)&3], 1)]^   \
	ft_tab[2][byte(bi[(n+2)&3], 2)]^   \
	ft_tab[3][byte(bi[(n+3)&3], 3)]^ *(k+n)
   
#define i_rn(bo,bi,n,k)               \
	bo[n]=it_tab[0][byte(bi[n],0)]^   \
	it_tab[1][byte(bi[(n+3)&3], 1)]^   \
	it_tab[2][byte(bi[(n+2)&3], 2)]^   \
	it_tab[3][byte(bi[(n+1)&3], 3)]^ *(k+n) 
 
#define rotr(x,n) (((x)>>((int)(n))) | ((x)<<(32-(int)(n))))
#define rotl(x,n) (((x)<<((int)(n))) | ((x)>>(32-(int)(n))))
 
#ifdef LARGE_TABLES
#define ls_box(x)     \
	(fl_tab[0][byte(x,0)]^fl_tab[1][byte(x,1)]^ \
	fl_tab[2][byte(x,2)]^fl_tab[3][byte(x,3)])
 
#define f_rl(bo,bi,n,k)              \
	bo[n]=fl_tab[0][byte(bi[n],0)]^   \
	fl_tab[1][byte(bi[(n+1)&3], 1)]^   \
	fl_tab[2][byte(bi[(n+2)&3], 2)]^   \
	fl_tab[3][byte(bi[(n+3)&3], 3)]^ *(k+n)
   
#define i_rn(bo,bi,n,k)              \
	bo[n]=il_tab[0][byte(bi[n],0)]^   \
	il_tab[1][byte(bi[(n+3)&3], 1)]^   \
	il_tab[2][byte(bi[(n+2)&3], 2)]^   \
	il_tab[3][byte(bi[(n+1)&3], 3)]^ *(k+n) 
#else
 
#define ls_box(x)           \
	((u4byte)sbx_tab[byte(x,0)]<<0)^((u4byte)sbx_tab[byte(x,1)]<<8)^ \
	((u4byte)sbx_tab[byte(x,2)]<<16)^((u4byte)sbx_tab[byte(x,3)]<<24)
 
 #define f_rl(bo,bi,n,k)                 \
	bo[n]=(u4byte)sbx_tab[byte(bi[n],0)] ^ \
	rotl(((u4byte)sbx_tab[byte(bi[(n+1)&3],1)]),8) ^  \
	rotl(((u4byte)sbx_tab[byte(bi[(n+2)&3],2)]),16) ^  \
	rotl(((u4byte)sbx_tab[byte(bi[(n+3)&3],3)]),24) ^*(k+n)

 #define i_rl(bo,bi,n,k)                 \
	bo[n]=(u4byte)isb_tab[byte(bi[n],0)] ^ \
	rotl(((u4byte)isb_tab[byte(bi[(n+3)&3],1)]),8) ^  \
	rotl(((u4byte)isb_tab[byte(bi[(n+2)&3],2)]),16) ^  \
	rotl(((u4byte)isb_tab[byte(bi[(n+1)&3],3)]),24) ^*(k+n)
 #endif
 
void gen_tabs(void)
{ 
	u4byte i, t;
	u1byte p, q;

	for(i=0, p=1; i<256; ++i)
	{
		pow_tab[i]=(u1byte)p; 
		log_tab[p]=(u1byte)i;
		p=p^(p<<1)^(p & 0x80 ? 0x1b :0);
	}

	log_tab[1]=0; p=1;

	for(i=0; i<10; ++i)
	{
		rco_tab[i]=p;
		p=(p<<1)^(p & 0x80 ? 0x1b :0);
	}

	for(i=0; i<256; ++i)
	{
		p=(i? pow_tab[255-log_tab[i]]: 0); 
		q=p;
		q=(q>>7) | (q<<1); 
		p^=q;
		q=(q>>7) | (q<<1); 
		p^=q;
		q=(q>>7) | (q<<1); 
		p^=q;
		q=(q>>7) | (q<<1); 
		p^=q^0x63;
		sbx_tab[i]=(u1byte)p; 
		isb_tab[p]=(u1byte)i;
	}

	for(i=0; i<256; ++i)
	{
		p=sbx_tab[i];

		#ifdef LARGE_TABLES
			t=p; 
			f1_tab[0][i]=t;
			f1_tab[1][i]=rot1(t, 8);
			f1_tab[2][i]=rot1(t, 16);
			f1_tab[3][i]=rot1(t, 24);
		#endif
		t=((u4byte)ff_mult(2,p))|((u4byte)p<<8)|
		((u4byte)p<<16)|((u4byte)ff_mult(3,p)<<24);

		ft_tab[0][i]=t; 
		ft_tab[1][i]=rotl(t,8);
		ft_tab[2][i]=rotl(t,16);
		ft_tab[3][i]=rotl(t,24);

		p=isb_tab[i];

		#ifdef LARGE_TABLES
			t=p;  il_tab[0][i]=t; il_tab[1][i]=rotl(t,8);
			il_tab[2][i]=rotl(t,16);il_tab[3][i]=rotl(t,24);
		#endif
		t=((u4byte)ff_mult(14,p))|((u4byte)ff_mult(9,p)<<8)|
		((u4byte)ff_mult(13,p)<<16)|((u4byte)ff_mult(11,p)<<24);

		it_tab[0][i]=t; 
		it_tab[1][i]=rotl(t,8);
		it_tab[2][i]=rotl(t,16);
		it_tab[3][i]=rotl(t,24);
	}
	tab_gen=1;
}
 
 #define star_x(x)  (((x)& 0x7f7f7f7f)<<1)^((((x) & 0x80808080)>>7)*0x1b)
 
 #define imix_col(y,x) \
 u=star_x(x); v=star_x(u); w=star_x(v);\
 t=w^(x); (y)=u^v^w; (y)^=rotr(u^t,8)^rotr(v^t,16)^rotr(t,24)
 

 
 #define loop6(i)     \
 { t=ls_box(rotl(t,8))^rotr(rco_tab[i], 8);\
   t^=e_key[6*i];     e_key[6*i+6]=t; \
   t^=e_key[6*i+1];     e_key[6*i+7]=t; \
   t^=e_key[6*i+2];     e_key[6*i+8]=t; \
   t^=e_key[6*i+3];     e_key[6*i+9]=t; \
   t^=e_key[6*i+4];     e_key[6*i+10]=t; \
   t^=e_key[6*i+5];     e_key[6*i+11]=t; \
 }
 
 #define loop8(i)     \
 { t=ls_box(rotl(t,8))^rotr(rco_tab[i], 8);\
   t^=e_key[8*i];     e_key[8*i+8]=t; \
   t^=e_key[8*i+1];     e_key[8*i+9]=t; \
   t^=e_key[8*i+2];     e_key[8*i+10]=t; \
   t^=e_key[8*i+3];     e_key[8*i+11]=t; \
   t^=e_key[8*i+4]^ls_box(t);  e_key[8*i+12]=t; \
   t^=e_key[8*i+5];     e_key[8*i+13]=t; \
   t^=e_key[8*i+6];     e_key[8*i+14]=t; \
   t^=e_key[8*i+7];     e_key[8*i+15]=t; \
 } 


void set_key(const u4byte in_key[], const u4byte key_len)
{ 
	u4byte i, t, u, v, w;

	if(!tab_gen)
		gen_tabs();

	k_len=(key_len+31)/32;

	e_key[0]=in_key[0];
	e_key[1]=in_key[1];
	e_key[2]=in_key[2]; 
	e_key[3]=in_key[3];

	switch(k_len)
	{
	//add round key 
	case 4: t=e_key[3];
		for(i=0; i<10; ++i)
		{
			t=ls_box(rotr(t,8))^rco_tab[i];
			t^=e_key[4*i];     
			e_key[4*i+4]=t; 
			t^=e_key[4*i+1];     
			e_key[4*i+5]=t; 
			t^=e_key[4*i+2];     
			e_key[4*i+6]=t; 
			t^=e_key[4*i+3];     
			e_key[4*i+7]=t; 
		};
		break;

	case 6: 
		e_key[4]=in_key[4]; 
		t=e_key[5]=in_key[5];
		for(i=0; i<8; ++i)
			loop6(i);
		break;

	case 8: 
		e_key[4]=in_key[4]; 
		e_key[5]=in_key[5];
		e_key[6]=in_key[6]; 
		t=e_key[7]=in_key[7];
		for(i=0; i<7; ++i)
			loop8(i);
		break;
	}

	d_key[0]=e_key[0]; 
	d_key[1]=e_key[1];
	d_key[2]=e_key[2]; 
	d_key[3]=e_key[3];

	for(i=4; i<4*k_len+24; ++i)
	{
		imix_col(d_key[i], e_key[i]);
	}
}
     
 #define f_nround(bo, bi, k) \
 f_rn(bo, bi, 0, k); f_rn(bo, bi, 1, k); \
 f_rn(bo, bi, 2, k); f_rn(bo, bi, 3, k); k+=4
 
 #define f_lround(bo, bi, k) \
 f_rl(bo, bi, 0, k); f_rl(bo, bi, 1, k); f_rl(bo, bi, 2, k); f_rl(bo, bi, 3, k)

void encrypt(const u4byte in_blk[4], u4byte out_blk[4])
{ 
	u4byte b0[4], b1[4], *kp;

	b0[0]=in_blk[0]^e_key[0]; 
	b0[1]=in_blk[1]^e_key[1];
	b0[2]=in_blk[2]^e_key[2]; 
	b0[3]=in_blk[3]^e_key[3];

	kp=e_key+4;

	if(k_len>6)
	{ 
		f_nround(b1, b0, kp);  
		f_nround(b0, b1, kp); 
	}

	if(k_len>4)
	{ 
		f_nround(b1, b0, kp);  
		f_nround(b0, b1, kp); 
	}

	f_nround(b1, b0, kp);  
	f_nround(b0, b1, kp); 
	f_nround(b1, b0, kp);  
	f_nround(b0, b1, kp); 
	f_nround(b1, b0, kp);  
	f_nround(b0, b1, kp); 
	f_nround(b1, b0, kp);  
	f_nround(b0, b1, kp); 
	f_nround(b1, b0, kp);  
	f_lround(b0, b1, kp);  

	out_blk[0]=b0[0]; 
	out_blk[1]=b0[1]; 
	out_blk[2]=b0[2]; 
	out_blk[3]=b0[3]; 
}

 #define i_nround(bo, bi, k) \
 i_rn(bo, bi, 0, k); i_rn(bo, bi, 1, k); \
 i_rn(bo, bi, 2, k); i_rn(bo, bi, 3, k); k-=4
 
 #define i_lround(bo, bi, k) \
 i_rl(bo, bi, 0, k); i_rl(bo, bi, 1, k); i_rl(bo, bi, 2, k); i_rl(bo, bi, 3, k)
 
void decrypt(const u4byte in_blk[4], u4byte out_blk[4])
{ 
	u4byte b0[4], b1[4], *kp;

	b0[0]=in_blk[0]^e_key[4*k_len+24]; 
	b0[1]=in_blk[1]^e_key[4*k_len+25];
	b0[2]=in_blk[2]^e_key[4*k_len+26]; 
	b0[3]=in_blk[3]^e_key[4*k_len+27];

	kp=d_key+4*(k_len+5);

	if(k_len>6)
	{
		i_nround(b1, b0, kp);  
		i_nround(b0, b1, kp); 
	}

	if(k_len>4)
	{
		i_nround(b1, b0, kp);  
		i_nround(b0, b1, kp); 
	}

	i_nround(b1, b0, kp);  
	i_nround(b0, b1, kp); 
	i_nround(b1, b0, kp);  
	i_nround(b0, b1, kp); 
	i_nround(b1, b0, kp);  
	i_nround(b0, b1, kp); 
	i_nround(b1, b0, kp);  
	i_nround(b0, b1, kp); 
	i_nround(b1, b0, kp);  
	i_lround(b0, b1, kp);  

	out_blk[0]=b0[0]; 
	out_blk[1]=b0[1]; 
	out_blk[2]=b0[2]; 
	out_blk[3]=b0[3]; 
}

//===============================================================================

typedef enum
{
	AES_ENCRYPT_128BIT = 128,
	AES_ENCRYPT_192BIT = 192,
	AES_ENCRYPT_256BIT = 256
} AES_ENC_bit;

#define	AES_ENCRYPT_BLOCK		16

/*
 *-----------------------------------------------------------------------------------------------------
 * int readFromFile(char* path,char** data)
 * purpose: This function read a file's content to a len size data by fp.
 * Params:
 *		Input: this file's path , data.
 *		Output: None.
 * Returns:	the length of this file.
 * Notes: None.
 * ----------------------------------------------------------------------------------------------------
 */
char *readFromFile(char* path, int *len)
{
	FILE* fp=NULL;
	char* data=NULL;
	size_t size=0;

	if (path == NULL)
		return NULL;
	if ((fp=fopen(path,"a+")) == NULL)
		return NULL;

	if (fseek(fp, 0L, SEEK_END) != 0)
		goto close_file;
	if ((size=ftell(fp)) == -1)
		goto close_file;
	
	data = (char*)malloc(size);
	if (data == NULL)
		goto close_file;

	*len = size;	
	rewind(fp);

	if (fread(data,1,size,fp) != size)
		goto close_file;		
		
	fclose(fp);
	return data;
	
close_file:
	fclose(fp);
	return NULL;
}

/*
 *-----------------------------------------------------------------------------------------------------
 * int writeToFile(FILE* fp, char *data, size_t len)
 * purpose: This function write a len size data to file pointed by fp.
 * Params:
 *		Input: file's path , data, data length.
 *		Output: None.
 * Returns:	Write result.
 * Notes: None.
 * ----------------------------------------------------------------------------------------------------
 */
int writeToFile(char* path, char* data, size_t len)
{
	FILE *fp = NULL;

	if (data == NULL)
		return 0;
	
	if ((fp=fopen(path,"w+")) == NULL)
		return 0;

	if (fwrite(data, 1, len, fp) != len)
	{
		fflush(fp);
		return 0;
	}

	fflush(fp);
	return 1;
}

/*
 *-----------------------------------------------------------------------------------------------------
 * int aes_encrypt(char* file_path, char* cipher_path, char* in_key, int key_len)
 * purpose: This function encode the plain file to the cipher file.
 * Params:
 *		Input: plain file'spath, cipher file's path, the secret key , the length of key
 *		Output: the cipher file.
 * Returns:	None.
 * Notes: None.
 * ----------------------------------------------------------------------------------------------------
 */
int aes_encrypt(char* file_path, char* cipher_path, char* key, int key_len)
{
	int block_len=0, file_len=0, rest_len = 0;
	char *buffer = NULL;
	char *exbuffer = NULL;
	char *pos;
	u4byte in_block[4], out_block[4];
	
	set_key((u4byte*)key, key_len);

	if ((buffer = readFromFile(file_path, &file_len)) == NULL)
		return 0;

	if ((exbuffer = (char *)malloc(file_len + AES_ENCRYPT_BLOCK)) == NULL)
	{
		free(buffer);
		return 0;	
	}
	else
	{
		memcpy(exbuffer, buffer, file_len);
		free(buffer);
	}

	rest_len = file_len + AES_ENCRYPT_BLOCK;
	pos = exbuffer;

	while (rest_len)
	{
		if (rest_len > AES_ENCRYPT_BLOCK)
			block_len = AES_ENCRYPT_BLOCK;
		else
			block_len = rest_len;
		
		memcpy((char*)in_block, pos, block_len);		
		encrypt(in_block, out_block);
		memcpy(pos, (char*)out_block, block_len);
		
		pos += block_len;
		rest_len -= block_len;
	}

	if (writeToFile(cipher_path, exbuffer, file_len + AES_ENCRYPT_BLOCK))
	{
		free(exbuffer);	
		return 1;
	}
	else
	{
		free(exbuffer);	
		return 0;
	}
}

/*
 *-----------------------------------------------------------------------------------------------------
 * int aes_decrypt(char* cipher_path, char* file_path, char* in_key, int key_len)
 * purpose: This function decode the cipher file to the plain file.
 * Params:
 *		Input: plain file'spath, cipher file's path, the secret key , the length of key
 *		Output: the plain file.
 * Returns:	None.
 * Notes: None.
 * ----------------------------------------------------------------------------------------------------
 */
int aes_decrypt(char* cipher_path, char* file_path, char* key, int key_len)
{
	int block_len=0, file_len=0, rest_len = 0;
	char *buffer = NULL;
	char *pos;
	u4byte in_block[4], out_block[4];
	
	set_key((u4byte*)key, key_len);

	if ((buffer = readFromFile(cipher_path, &file_len)) == NULL)
		return 0;
		
	rest_len = file_len;
	pos = buffer;
	
	while (rest_len)
	{
		if (rest_len > AES_ENCRYPT_BLOCK)
			block_len = AES_ENCRYPT_BLOCK;
		else
			block_len = rest_len;
		
		memcpy((char*)in_block, pos, block_len);
		decrypt(in_block, out_block);
		memcpy(pos, (char*)out_block, block_len);
		
		pos += block_len;
		rest_len -= block_len;
	}

	if (writeToFile(file_path, buffer, file_len - AES_ENCRYPT_BLOCK))
	{
		free(buffer);
		return 1;
	}
	else
	{
		free(buffer);
		return 0;
	}		
}

#if 0
int aes_demo(void)
{
	char file_path[64]={0};
	char cipher_path[64]={0};
	char key[80]={0};
	
	strcpy(key,"2sgwret3457erasd");
	
	strcpy(file_path,"mail.txt");
	strcpy(cipher_path,"mail.aes");
	aes_encrypt(file_path, cipher_path, key, AES_ENCRYPT_128BIT);

	strcpy(file_path,"mail2.txt");
	aes_decrypt(cipher_path, file_path, key, AES_ENCRYPT_128BIT);
	
	return 1;
}

int main()
{
	return aes_demo();
}
#endif