aes.c

该文件可以用VC++6.0打开编译实现加密解密功能

}

//AES加密函数
void AES_encrypt(const byte in[16], byte out[16], const byte key[16])
{
    word state[4], temp[4], key_ex[44];
    int i;

    for (i = 0; i < 4; i++)
        state[i] = Byte2Word(&in[i*4]);

    KeyExpansion(key, key_ex);

    AddRoundKey(state, &key_ex[0]);

    for (i = 1; i < 10; i++) {
        MixColumns_ShifRows(state);
        AddRoundKey(state, &key_ex[i*4]);
    }

    temp[0] =
        sbox[(byte)(state[0])] |
        sbox[(byte)(state[1] >>  8)] <<  8 |
        sbox[(byte)(state[2] >> 16)] << 16 |
        sbox[(byte)(state[3] >> 24)] << 24;

    temp[1] =
        sbox[(byte)(state[1])] |
        sbox[(byte)(state[2] >>  8)] <<  8 |
        sbox[(byte)(state[3] >> 16)] << 16 |
        sbox[(byte)(state[0] >> 24)] << 24;

    temp[2] =
        sbox[(byte)(state[2])] |
        sbox[(byte)(state[3] >>  8)] <<  8 |
        sbox[(byte)(state[0] >> 16)] << 16 |
        sbox[(byte)(state[1] >> 24)] << 24;

    temp[3] =
        sbox[(byte)(state[3])] |
        sbox[(byte)(state[0] >>  8)] <<  8 |
        sbox[(byte)(state[1] >> 16)] << 16 |
        sbox[(byte)(state[2] >> 24)] << 24;

    AddRoundKey(temp, &key_ex[i*4]);

    for (i = 0; i < 4; i++)
        Word2Byte(temp[i], &out[i*4]);
}

//AES解密函数
void AES_decrypt(const byte in[16], byte out[16], const byte key[16])
{
    word state[4], temp[4], key_ex[44];
    int i;

    for (i = 0; i < 4; i++)
        state[i] = Byte2Word(&in[i*4]);

    KeyExpansion(key, key_ex);
    for (i = 1; i < 10; i++) {
        InvMixColumns(&key_ex[i*4]);
    }

    AddRoundKey(state, &key_ex[10 * 4]);

    for (i = 9; i > 0; i--) {
        state[0] = InvSubWord(state[0]);
        state[1] = InvSubWord(state[1]);
        state[2] = InvSubWord(state[2]);
        state[3] = InvSubWord(state[3]);

        InvMixColumns_ShiftRows(state);
        AddRoundKey(state, &key_ex[i*4]);
    }

    temp[0] =
        invsbox[(byte)(state[0])] |
        invsbox[(byte)(state[3] >>  8)] <<  8 |
        invsbox[(byte)(state[2] >> 16)] << 16 |
        invsbox[(byte)(state[1] >> 24)] << 24;

    temp[1] =
        invsbox[(byte)(state[1])] |
        invsbox[(byte)(state[0] >>  8)] <<  8 |
        invsbox[(byte)(state[3] >> 16)] << 16 |
        invsbox[(byte)(state[2] >> 24)] << 24;

    temp[2] =
        invsbox[(byte)(state[2])] |
        invsbox[(byte)(state[1] >>  8)] <<  8 |
        invsbox[(byte)(state[0] >> 16)] << 16 |
        invsbox[(byte)(state[3] >> 24)] << 24;

    temp[3] =
        invsbox[(byte)(state[3])] |
        invsbox[(byte)(state[2] >>  8)] <<  8 |
        invsbox[(byte)(state[1] >> 16)] << 16 |
        invsbox[(byte)(state[0] >> 24)] << 24;

    AddRoundKey(temp, &key_ex[i*4]);

    for (i = 0; i < 4; i++)
        Word2Byte(temp[i], &out[i*4]);
}

/* int main() */
/* { */
/*     byte a[16] = {0, 1, 2, 3, 4, 5, 6, 7, */
/*                   8, 9, 10, 11, 12, 13, 14, 15}; */
/*     word w[44]; */

/*     word b[4] = {0x3d7c6ebd, 0x9e77b5f2, 0x6e21610b, 0x89b6108b}; */

/*     byte key[16] = {0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, */
/*                     0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C }; */
/*     int i; */

/*     byte input[] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, */
/*                     0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff}; */
/*     byte ckey[] = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, */
/*                    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f}; */
/*     byte output[16]; */


/*     clock_t start, finish; */
/*     double duration; */

/*     start = clock(); */
/*     for (i = 0; i < 1000000; i++) */
/*         AES_encrypt(input, output, ckey); */
/*     finish = clock(); */
/*     duration = (double)(finish - start) / CLOCKS_PER_SEC; */
/*     printf("%lf\n", duration); */

/*     for (i = 0; i < 16; i++) */
/*         printf("%02x", output[i]); */
/*     printf("\n"); */
    
/*     return 0; */
/* } */


//AES文件加密函数
/*
    文件加密采用ECB模式,也就是电话簿模式,别的模式有待实现
    最后在文件的尾部写入加密文件的大小(当然也是加密过的数据)
    @param fr  需要加密的文件
    @param fw  加密后输出的文件
    @param key 加密所需的密钥
*/
int AES_file_encrypt(const char* fr, const char* fw, const byte key[16])
{
    byte buf[BLOCK_SIZE];
    FILE *fp_r, *fp_w;
    int i, r_size;

    if ((fp_r = fopen(fr, "rb")) == NULL) {
        fprintf(stderr, "Error reading file.");
        return 1;
    }
    if ((fp_w = fopen(fw, "wb")) == NULL) {
        fprintf(stderr, "Error reading file.");
        fclose(fp_r);
        return 1;
    }

    //读入初始的文件块
    r_size = fread(buf, sizeof(byte), BLOCK_SIZE, fp_r);
    while (r_size == BLOCK_SIZE) {
        //加密文件快
        AES_encrypt(buf, buf, key);
        //写入到文件
        fwrite(buf, sizeof(byte), BLOCK_SIZE, fp_w);
        //读入下一个块
        r_size = fread(buf, sizeof(byte), BLOCK_SIZE, fp_r);
    }

    //如果不是文件结束,返回错误值
    if (!feof(fp_r)) {
        fprintf(stderr, "Error reading file in feof.");
        fclose(fp_r);
        fclose(fp_w);
        return 1;
    }

    //写入最后一块,不够16位的补零
    for (i = r_size; i < BLOCK_SIZE; i++)
        buf[i] = 0;
    AES_encrypt(buf, buf, key);
    fwrite(buf, sizeof(byte), BLOCK_SIZE, fp_w);

    *((int *)buf) = ftell(fp_r);
    AES_encrypt(buf, buf, key);
    //写入文件大小,放在最后
    fwrite(buf, sizeof(byte), BLOCK_SIZE, fp_w);

/*     for (i = 0; i < BLOCK_SIZE; i++) */
/*         printf("%02x ", buf[i]); */
/*     printf("\n"); */
/*         printf("last count:%d\n", r_size); */

    fclose(fp_r);
    fclose(fp_w);

    return 0;
}

//AES文件解密密函数
/*
    文件解密密同样采用ECB模式
    @param fr  需要解密的文件
    @param fw  解密后输出的文件
    @param key 解密所需的密钥
*/
int AES_file_decrypt(const char* fr, const char* fw, const byte key[16])
{
    byte buf1[BLOCK_SIZE], buf2[BLOCK_SIZE], buf3[BLOCK_SIZE],
        *p, *q, *r, *t;
    FILE *fp_r, *fp_w;
    int r_size, diff;

    if ((fp_r = fopen(fr, "rb")) == NULL) {
        fprintf(stderr, "Error reading file.");
        return 1;
    }
    if ((fp_w = fopen(fw, "wb")) == NULL) {
        fprintf(stderr, "Error reading file.");
        fclose(fp_r);
        return 1;
    }

    p = buf1, q = buf2, r = buf3;
    r_size = fread(p, sizeof(byte), BLOCK_SIZE, fp_r);

    //读入初始的两块
    if (r_size != BLOCK_SIZE) {
        fprintf(stderr, "Decrypt file failed");
        fclose(fp_r);
        fclose(fp_w);
        return 1;
    }
    r_size = fread(q, sizeof(byte), BLOCK_SIZE, fp_r);
    if (r_size != BLOCK_SIZE) {
        fprintf(stderr, "Decrypt file failed");
        fclose(fp_r);
        fclose(fp_w);
        return 1;
    }
    r_size = fread(r, sizeof(byte), BLOCK_SIZE, fp_r);

    while (r_size == BLOCK_SIZE) {
        //先解密然后再写入
        AES_decrypt(p, p, key);
        fwrite(p, sizeof(byte), BLOCK_SIZE, fp_w);
        t = p; p = q; q = r; r = t;
        //读入下一块
        r_size = fread(r, sizeof(byte), BLOCK_SIZE, fp_r);

/*         for (i = 0; i < BLOCK_SIZE; i++) */
/*             printf("%02x ", p[i]); */
/*         printf("\n"); */
/*         for (i = 0; i < BLOCK_SIZE; i++) */
/*             printf("%02x ", q[i]); */
/*         printf("\n"); */
/*         for (i = 0; i < BLOCK_SIZE; i++) */
/*             printf("%02x ", r[i]); */
/*         printf("\n"); */
    }

    if (!feof(fp_r)) {
        fprintf(stderr, "Error reading file in feof.");
        fclose(fp_r);
        fclose(fp_w);
        return 1;
    }

    //解密最后的两块,最后一块放的是加密前文件的大小
    AES_decrypt(p, p, key);
    AES_decrypt(q, q, key);

    //计算倒数第二块的大小,并写入
    diff = 32 + *(int *)q - ftell(fp_r);
    if (diff > 0 && diff < 16)
        fwrite(p, sizeof(byte), diff, fp_w);

    fclose(fp_r);
    fclose(fp_w);

    return 0;
}


/*
 * 实例：
 * 加密接口：   AES_file_encrypt
 * 解密接口：	AES_file_decrypt
 */
int main()
{
       //密钥   可以自己修改	
     byte ckey[] = {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 
                    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f}; 

     clock_t start, finish; 
     double duration; 
     start = clock(); 

     //对文件进行加密：  第一个参数"enc.rar"是所需要加密的文件，第二个参数enc.rar.enc是加密后的文件名，
     //第三个参数是上面自己设置的密钥
     AES_file_encrypt("enc.rar", "enc.rar.enc", ckey); 
     //对已加过密的文件进行解密： 其中"enc.rar.dec"是解密后的文件。
     AES_file_decrypt("enc.rar.enc", "enc.rar.dec", ckey); 
/*
     AES_file_encrypt("aes.o", "aes.o.enc", ckey); 
     AES_file_decrypt("aes.o.enc", "aes.o.dec", ckey); 
*/
     finish = clock(); 
     duration = (double)(finish - start) / CLOCKS_PER_SEC; 
     printf("%lf", duration); 

     return 0; 
 }