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[原创] KCTF2022——第三题 石像病毒题解
2022-5-14 11:54 2872

[原创] KCTF2022——第三题 石像病毒题解

2022-5-14 11:54
2872

程序无壳,运行情况:

程序主要流程:

  • 读取输入,限制输入长度必须等于 32字节
  • 对字符串 “ Enj0y_1t_4_fuuuN”进行魔改的 MD5加密,加密结果为 {0x2F,0x65,0xB1,0xFF,0x31,0xED,0x86,0xD0,0x9A,0x28,0x5C,0x0F,0x40,0x48,0x05,0x9D},以此作为秘钥,对输入的数据进行魔改的 AES加密

    AES加密流程

    AES主要有两处位置进行了魔改:

    1. AES加密前会修改 S

    2. 行位移中将循环左移改成了循环右移,这段代码在 IDA中无法正常反编译,可以通过动态调试观察出来

  • 将加密结果也正确的加密结果比较,相同则输出 OK

    最后说说自己在动态调试中的遭遇以及心得:程序中藏了很多暗桩,在动态调试的时候会故意引导单步执行一些导致异常的指令,然后又在异常处理函数中修正 PC指针。所以断点如果下不好位置就很容易导致程序跑飞,跟丢目标。

解题脚本

 

AES.h

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#include <stdint.h>
#include <stdio.h>
#include <string.h>
 
typedef struct {
    uint32_t eK[44], dK[44];    // encKey, decKey
    int Nr; // 10 rounds
}AesKey;
 
#define BLOCKSIZE 16  //AES-128分组长度为16字节
 
// uint8_t y[4] -> uint32_t x
#define LOAD32H(x, y) \
  do { (x) = ((uint32_t)((y)[0] & 0xff)<<24) | ((uint32_t)((y)[1] & 0xff)<<16) | \
             ((uint32_t)((y)[2] & 0xff)<<8)  | ((uint32_t)((y)[3] & 0xff));} while(0)
 
// uint32_t x -> uint8_t y[4]
#define STORE32H(x, y) \
  do { (y)[0] = (uint8_t)(((x)>>24) & 0xff); (y)[1] = (uint8_t)(((x)>>16) & 0xff);   \
       (y)[2] = (uint8_t)(((x)>>8) & 0xff); (y)[3] = (uint8_t)((x) & 0xff); } while(0)
 
// 从uint32_t x中提取从低位开始的第n个字节
#define BYTE(x, n) (((x) >> (8 * (n))) & 0xff)
 
/* used for keyExpansion */
// 字节替换然后循环左移1
#define MIX(x) (((S[BYTE(x, 2)] << 24) & 0xff000000) ^ ((S[BYTE(x, 1)] << 16) & 0xff0000) ^ \
                ((S[BYTE(x, 0)] << 8) & 0xff00) ^ (S[BYTE(x, 3)] & 0xff))
 
// uint32_t x循环左移n位
#define ROF32(x, n)  (((x) << (n)) | ((x) >> (32-(n))))
// uint32_t x循环右移n位
#define ROR32(x, n)  (((x) >> (n)) | ((x) << (32-(n))))
 
/* for 128-bit blocks, Rijndael never uses more than 10 rcon values */
// AES-128轮常量
static const uint32_t rcon[10] = {
        0x01000000UL, 0x02000000UL, 0x04000000UL, 0x08000000UL, 0x10000000UL,
        0x20000000UL, 0x40000000UL, 0x80000000UL, 0x1B000000UL, 0x36000000UL
};
// S盒
//unsigned char S[256] = {
//        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
//};
 
unsigned char S[256] = {
    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,0xA8,0x51,0x0A,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,0xA3,0x49,0x06,0x24,0x5C,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
};
 
//逆S盒
//unsigned char inv_S[256] = {
//        0x52, 0x09, 0x6A, 0xD5, 0x30, 0x36, 0xA5, 0x38, 0xBF, 0x40, 0xA3, 0x9E, 0x81, 0xF3, 0xD7, 0xFB,
//        0x7C, 0xE3, 0x39, 0x82, 0x9B, 0x2F, 0xFF, 0x87, 0x34, 0x8E, 0x43, 0x44, 0xC4, 0xDE, 0xE9, 0xCB,
//        0x54, 0x7B, 0x94, 0x32, 0xA6, 0xC2, 0x23, 0x3D, 0xEE, 0x4C, 0x95, 0x0B, 0x42, 0xFA, 0xC3, 0x4E,
//        0x08, 0x2E, 0xA1, 0x66, 0x28, 0xD9, 0x24, 0xB2, 0x76, 0x5B, 0xA2, 0x49, 0x6D, 0x8B, 0xD1, 0x25,
//        0x72, 0xF8, 0xF6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xD4, 0xA4, 0x5C, 0xCC, 0x5D, 0x65, 0xB6, 0x92,
//        0x6C, 0x70, 0x48, 0x50, 0xFD, 0xED, 0xB9, 0xDA, 0x5E, 0x15, 0x46, 0x57, 0xA7, 0x8D, 0x9D, 0x84,
//        0x90, 0xD8, 0xAB, 0x00, 0x8C, 0xBC, 0xD3, 0x0A, 0xF7, 0xE4, 0x58, 0x05, 0xB8, 0xB3, 0x45, 0x06,
//        0xD0, 0x2C, 0x1E, 0x8F, 0xCA, 0x3F, 0x0F, 0x02, 0xC1, 0xAF, 0xBD, 0x03, 0x01, 0x13, 0x8A, 0x6B,
//        0x3A, 0x91, 0x11, 0x41, 0x4F, 0x67, 0xDC, 0xEA, 0x97, 0xF2, 0xCF, 0xCE, 0xF0, 0xB4, 0xE6, 0x73,
//        0x96, 0xAC, 0x74, 0x22, 0xE7, 0xAD, 0x35, 0x85, 0xE2, 0xF9, 0x37, 0xE8, 0x1C, 0x75, 0xDF, 0x6E,
//        0x47, 0xF1, 0x1A, 0x71, 0x1D, 0x29, 0xC5, 0x89, 0x6F, 0xB7, 0x62, 0x0E, 0xAA, 0x18, 0xBE, 0x1B,
//        0xFC, 0x56, 0x3E, 0x4B, 0xC6, 0xD2, 0x79, 0x20, 0x9A, 0xDB, 0xC0, 0xFE, 0x78, 0xCD, 0x5A, 0xF4,
//        0x1F, 0xDD, 0xA8, 0x33, 0x88, 0x07, 0xC7, 0x31, 0xB1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xEC, 0x5F,
//        0x60, 0x51, 0x7F, 0xA9, 0x19, 0xB5, 0x4A, 0x0D, 0x2D, 0xE5, 0x7A, 0x9F, 0x93, 0xC9, 0x9C, 0xEF,
//        0xA0, 0xE0, 0x3B, 0x4D, 0xAE, 0x2A, 0xF5, 0xB0, 0xC8, 0xEB, 0xBB, 0x3C, 0x83, 0x53, 0x99, 0x61,
//        0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26, 0xE1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0C, 0x7D
//};
 
unsigned char inv_S[256] = { 0x52,0x9,0x6a,0xd5,0x30,0x36,0xa5,0x38,0xbf,0x40,0x71,0x9e,0x81,0xf3,0xd7,0xfb,0x7c,0xe3,0x39,0x82,0x9b,0x2f,0xff,0x87,0x34,0x8e,0x43,0x44,0xc4,0xde,0xe9,0xcb,0x54,0x7b,0x94,0x32,0xa6,0xc2,0x23,0x3d,0xee,0x4c,0x95,0xb,0x42,0xfa,0xc3,0x4e,0x8,0x2e,0xa1,0x66,0x28,0xd9,0x24,0xb2,0x76,0x5b,0xa2,0x49,0x6d,0x8b,0xd1,0x25,0x72,0xf8,0xf6,0x64,0x86,0x68,0x98,0x16,0xd4,0xa4,0x5c,0xcc,0x5d,0x65,0xb6,0x92,0x6c,0x70,0x48,0x50,0xfd,0xed,0xb9,0xda,0x5e,0x15,0x46,0x57,0xa7,0x8d,0x9d,0x84,0x90,0xd8,0xab,0x0,0x8c,0xbc,0xd3,0xa,0xf7,0xe4,0x58,0x5,0xb8,0xb3,0x45,0x6,0xd0,0x2c,0x1e,0x8f,0xca,0x3f,0xf,0x2,0xc1,0xaf,0xbd,0x3,0x1,0x13,0x8a,0x6b,0x3a,0x91,0x11,0x41,0x4f,0x67,0xdc,0xea,0x97,0xf2,0xcf,0xce,0xf0,0xb4,0xe6,0x73,0x96,0xac,0x74,0x22,0xe7,0xad,0x35,0x85,0xe2,0xf9,0x37,0xe8,0x1c,0x75,0xdf,0x6e,0x47,0xf1,0x1a,0xa3,0x1d,0x29,0xc5,0x89,0x6f,0xb7,0x62,0xe,0xaa,0x18,0xbe,0x1b,0xfc,0x56,0x3e,0x4b,0xc6,0xd2,0x79,0x20,0x9a,0xdb,0xc0,0xfe,0x78,0xcd,0x5a,0xf4,0x1f,0xdd,0xa8,0x33,0x88,0x7,0xc7,0x31,0xb1,0x12,0x10,0x59,0x27,0x80,0xec,0x5f,0x60,0x51,0x7f,0xa9,0x19,0xb5,0x4a,0xd,0x2d,0xe5,0x7a,0x9f,0x93,0xc9,0x9c,0xef,0xa0,0xe0,0x3b,0x4d,0xae,0x2a,0xf5,0xb0,0xc8,0xeb,0xbb,0x3c,0x83,0x53,0x99,0x61,0x17,0x2b,0x4,0x7e,0xba,0x77,0xd6,0x26,0xe1,0x69,0x14,0x63,0x55,0x21,0xc,0x7d };
 
/* copy in[16] to state[4][4] */
int loadStateArray(uint8_t(*state)[4], const uint8_t* in) {
    for (int i = 0; i < 4; ++i) {
        for (int j = 0; j < 4; ++j) {
            state[j][i] = *in++;
        }
    }
    return 0;
}
 
/* copy state[4][4] to out[16] */
int storeStateArray(uint8_t(*state)[4], uint8_t* out) {
    for (int i = 0; i < 4; ++i) {
        for (int j = 0; j < 4; ++j) {
            *out++ = state[j][i];
        }
    }
    return 0;
}
//秘钥扩展
int keyExpansion(const uint8_t* key, uint32_t keyLen, AesKey* aesKey) {
 
    if (NULL == key || NULL == aesKey) {
        printf("keyExpansion param is NULL\n");
        return -1;
    }
 
    if (keyLen != 16) {
        printf("keyExpansion keyLen = %d, Not support.\n", keyLen);
        return -1;
    }
 
    uint32_t* w = aesKey->eK;  //加密秘钥
    uint32_t* v = aesKey->dK;  //解密秘钥
 
    /* keyLen is 16 Bytes, generate uint32_t W[44]. */
 
    /* W[0-3] */
    for (int i = 0; i < 4; ++i) {
        LOAD32H(w[i], key + 4 * i);
    }
 
    /* W[4-43] */
    for (int i = 0; i < 10; ++i) {
        w[4] = w[0] ^ MIX(w[3]) ^ rcon[i];
        w[5] = w[1] ^ w[4];
        w[6] = w[2] ^ w[5];
        w[7] = w[3] ^ w[6];
        w += 4;
    }
 
    w = aesKey->eK + 44 - 4;
    //解密秘钥矩阵为加密秘钥矩阵的倒序,方便使用,把ek的11个矩阵倒序排列分配给dk作为解密秘钥
    //即dk[0-3]=ek[41-44], dk[4-7]=ek[37-40]... dk[41-44]=ek[0-3]
    for (int j = 0; j < 11; ++j) {
 
        for (int i = 0; i < 4; ++i) {
            v[i] = w[i];
        }
        w -= 4;
        v += 4;
    }
 
    return 0;
}
 
// 轮秘钥加
int addRoundKey(uint8_t(*state)[4], const uint32_t* key) {
    uint8_t k[4][4];
 
    /* i: row, j: col */
    for (int i = 0; i < 4; ++i) {
        for (int j = 0; j < 4; ++j) {
            k[i][j] = (uint8_t)BYTE(key[j], 3 - i);  /* 把 uint32 key[4] 先转换为矩阵 uint8 k[4][4] */
            state[i][j] ^= k[i][j];
        }
    }
 
    return 0;
}
 
//字节替换
int subBytes(uint8_t(*state)[4]) {
    /* i: row, j: col */
    for (int i = 0; i < 4; ++i) {
        for (int j = 0; j < 4; ++j) {
            state[i][j] = S[state[i][j]]; //直接使用原始字节作为S盒数据下标
        }
    }
 
    return 0;
}
 
//逆字节替换
int invSubBytes(uint8_t(*state)[4]) {
    /* i: row, j: col */
    for (int i = 0; i < 4; ++i) {
        for (int j = 0; j < 4; ++j) {
            state[i][j] = inv_S[state[i][j]];
        }
    }
    return 0;
}
 
//行移位
int shiftRows(uint8_t(*state)[4]) {
    uint32_t block[4] = { 0 };
 
    /* i: row */
    for (int i = 0; i < 4; ++i) {
        //便于行循环移位,先把一行4字节拼成uint_32结构,移位后再转成独立的4个字节uint8_t
        LOAD32H(block[i], state[i]);
        //block[i] = ROF32(block[i], 8 * i);
        block[i] = ROR32(block[i], 8 * i);
        STORE32H(block[i], state[i]);
 
 
    }
 
    return 0;
}
 
//逆行移位
int invShiftRows(uint8_t(*state)[4]) {
    uint32_t block[4] = { 0 };
 
    /* i: row */
    for (int i = 0; i < 4; ++i) {
        LOAD32H(block[i], state[i]);
        //block[i] = ROR32(block[i], 8 * i);
        block[i] = ROF32(block[i], 8 * i);
        STORE32H(block[i], state[i]);
    }
 
    return 0;
}
 
/* Galois Field (256) Multiplication of two Bytes */
// 两字节的伽罗华域乘法运算
uint8_t GMul(uint8_t u, uint8_t v) {
    uint8_t p = 0;
 
    for (int i = 0; i < 8; ++i) {
        if (u & 0x01) {    //
            p ^= v;
        }
 
        int flag = (v & 0x80);
        v <<= 1;
        if (flag) {
            v ^= 0x1B; /* x^8 + x^4 + x^3 + x + 1 */
        }
 
        u >>= 1;
    }
 
    return p;
}
 
// 列混合
int mixColumns(uint8_t(*state)[4]) {
    uint8_t tmp[4][4];
    uint8_t M[4][4] = { {0x02, 0x03, 0x01, 0x01},
                       {0x01, 0x02, 0x03, 0x01},
                       {0x01, 0x01, 0x02, 0x03},
                       {0x03, 0x01, 0x01, 0x02} };
 
    /* copy state[4][4] to tmp[4][4] */
    for (int i = 0; i < 4; ++i) {
        for (int j = 0; j < 4; ++j) {
            tmp[i][j] = state[i][j];
        }
    }
 
    for (int i = 0; i < 4; ++i) {
        for (int j = 0; j < 4; ++j) {  //伽罗华域加法和乘法
            state[i][j] = GMul(M[i][0], tmp[0][j]) ^ GMul(M[i][1], tmp[1][j])
                ^ GMul(M[i][2], tmp[2][j]) ^ GMul(M[i][3], tmp[3][j]);
        }
    }
 
    return 0;
}
 
// 逆列混合
int invMixColumns(uint8_t(*state)[4]) {
    uint8_t tmp[4][4];
    uint8_t M[4][4] = { {0x0E, 0x0B, 0x0D, 0x09},
                       {0x09, 0x0E, 0x0B, 0x0D},
                       {0x0D, 0x09, 0x0E, 0x0B},
                       {0x0B, 0x0D, 0x09, 0x0E} };  //使用列混合矩阵的逆矩阵
 
    /* copy state[4][4] to tmp[4][4] */
    for (int i = 0; i < 4; ++i) {
        for (int j = 0; j < 4; ++j) {
            tmp[i][j] = state[i][j];
        }
    }
 
    for (int i = 0; i < 4; ++i) {
        for (int j = 0; j < 4; ++j) {
            state[i][j] = GMul(M[i][0], tmp[0][j]) ^ GMul(M[i][1], tmp[1][j])
                ^ GMul(M[i][2], tmp[2][j]) ^ GMul(M[i][3], tmp[3][j]);
        }
    }
 
    return 0;
}
 
// AES-128加密接口,输入key应为16字节长度,输入长度应该是16字节整倍数,
// 这样输出长度与输入长度相同,函数调用外部为输出数据分配内存
int aesEncrypt(const uint8_t* key, uint32_t keyLen, const uint8_t* pt, uint8_t* ct, uint32_t len) {
 
    AesKey aesKey;
    uint8_t* pos = ct;
    const uint32_t* rk = aesKey.eK;  //解密秘钥指针
    uint8_t out[BLOCKSIZE] = { 0 };
    uint8_t actualKey[16] = { 0 };
    uint8_t state[4][4] = { 0 };
 
    if (NULL == key || NULL == pt || NULL == ct) {
        printf("param err.\n");
        return -1;
    }
 
    if (keyLen > 16) {
        printf("keyLen must be 16.\n");
        return -1;
    }
 
    if (len % BLOCKSIZE) {
        printf("inLen is invalid.\n");
        return -1;
    }
 
    memcpy(actualKey, key, keyLen);
    keyExpansion(actualKey, 16, &aesKey);  // 秘钥扩展
 
    // 使用ECB模式循环加密多个分组长度的数据
    for (int i = 0; i < len; i += BLOCKSIZE) {
        // 16字节的明文转换为4x4状态矩阵来进行处理
        loadStateArray(state, pt);
        // 轮秘钥加
        addRoundKey(state, rk);
 
        for (int j = 1; j < 10; ++j) {
            rk += 4;
            subBytes(state);   // 字节替换
            shiftRows(state);  // 行移位
            mixColumns(state); // 列混合
            addRoundKey(state, rk); // 轮秘钥加
        }
 
        subBytes(state);    // 字节替换
        shiftRows(state);  // 行移位
        // 此处不进行列混合
        addRoundKey(state, rk + 4); // 轮秘钥加
 
        // 4x4状态矩阵转换为uint8_t一维数组输出保存
        storeStateArray(state, pos);
 
        pos += BLOCKSIZE;  // 加密数据内存指针移动到下一个分组
        pt += BLOCKSIZE;   // 明文数据指针移动到下一个分组
        rk = aesKey.eK;    // 恢复rk指针到秘钥初始位置
    }
    return 0;
}
 
// AES128解密, 参数要求同加密
int aesDecrypt(const uint8_t* key, uint32_t keyLen, const uint8_t* ct, uint8_t* pt, uint32_t len) {
    AesKey aesKey;
    uint8_t* pos = pt;
    const uint32_t* rk = aesKey.dK;  //解密秘钥指针
    uint8_t out[BLOCKSIZE] = { 0 };
    uint8_t actualKey[16] = { 0 };
    uint8_t state[4][4] = { 0 };
 
    if (NULL == key || NULL == ct || NULL == pt) {
        printf("param err.\n");
        return -1;
    }
 
    if (keyLen > 16) {
        printf("keyLen must be 16.\n");
        return -1;
    }
 
    if (len % BLOCKSIZE) {
        printf("inLen is invalid.\n");
        return -1;
    }
 
    memcpy(actualKey, key, keyLen);
    keyExpansion(actualKey, 16, &aesKey);  //秘钥扩展,同加密
 
    for (int i = 0; i < len; i += BLOCKSIZE) {
        // 16字节的密文转换为4x4状态矩阵来进行处理
        loadStateArray(state, ct);
        // 轮秘钥加,同加密
        addRoundKey(state, rk);
 
        for (int j = 1; j < 10; ++j) {
            rk += 4;
            invShiftRows(state);    // 逆行移位
            invSubBytes(state);     // 逆字节替换,这两步顺序可以颠倒
            addRoundKey(state, rk); // 轮秘钥加,同加密
            invMixColumns(state);   // 逆列混合
        }
 
        invSubBytes(state);   // 逆字节替换
        invShiftRows(state);  // 逆行移位
        // 此处没有逆列混合
        addRoundKey(state, rk + 4);  // 轮秘钥加,同加密
 
        storeStateArray(state, pos);  // 保存明文数据
        pos += BLOCKSIZE;  // 输出数据内存指针移位分组长度
        ct += BLOCKSIZE;   // 输入数据内存指针移位分组长度
        rk = aesKey.dK;    // 恢复rk指针到秘钥初始位置
    }
    return 0;
}
 
 
void GetInvSBox(uint8_t* sbox,uint8_t* inv_sbox)
{
    int l, r;
    for (int i = 0; i < 0x100; i++)
    {
        l = (sbox[i] & 0xf0) >> 4;
        r = sbox[i] & 0xf;
        inv_sbox[l * 16 + r] = i;
    }
}
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#include<stdio.h>
#include<stdlib.h>
#include "AES.h"
 
int main() {
    unsigned char key[16] = { 0x2F,0x65,0xB1,0xFF,0x31,0xED,0x86,0xD0,0x9A,0x28,0x5C,0x0F,0x40,0x48,0x05,0x9D};
    unsigned char plain[33] = { 0 };
    unsigned char cipher[] = {0x57,0x7C,0xF5,0x6D,0x56,0x96,0x77,0x45,0xB0,0xBD,0xA1,0xC7,0x89,0xA5,0xAB,0xDC,0xF4,0xF2,0x4B,0xFE,0xBE,0xF5,0xF5,0x5C,0x4D,0x30,0x42,0x0F,0x2B,0x3B,0xE6,0xCB};
 
    aesDecrypt((uint8_t*)key, 16, cipher, plain, 32);
 
    printf("%s\n", (char*)plain);
 
    system("pause");
    return 0;
}

2022 KCTF春季赛【最佳人气奖】火热评选中!快来投票吧~

最后于 2022-5-14 11:55 被brucy编辑 ,原因: 修改标题
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