高级加密在逆向中初探

笔记

get_s_box_aes.c

#include <stdio.h>
 
int main()
{
    unsigned char sbox[256] = 
    { 
        0xE3, 0xFD, 0xF5, 0x30, 0x50, 0xBD, 0x51, 0x70, 0x3D, 0x40, 0x16, 0x04, 0x4D, 0xB5, 0xC0, 0xA2,
0x6D, 0xE2, 0x56, 0xC4, 0xA9, 0x54, 0x7F, 0x27, 0x66, 0x82, 0xD6, 0x68, 0xFB, 0x57, 0xCA, 0xC3,
0x6F, 0xA4, 0xF0, 0xD5, 0x2A, 0xE8, 0xC1, 0x0A, 0x5E, 0x19, 0x79, 0x4B, 0x69, 0x45, 0xF1, 0xA7,
0x87, 0x00, 0xD8, 0xDC, 0xC2, 0xA5, 0xA6, 0x29, 0x5B, 0xCE, 0x07, 0xF4, 0x84, 0x97, 0x9F, 0xE0,
0xA0, 0xDE, 0x22, 0xB4, 0x58, 0x5F, 0x3A, 0x5D, 0xA3, 0x2B, 0x71, 0xF2, 0xB6, 0x44, 0x37, 0x9E,
0xC9, 0xAB, 0x01, 0x12, 0x09, 0x83, 0xD4, 0x93, 0xD9, 0xBE, 0x02, 0x35, 0xF8, 0xAA, 0xEE, 0xE5,
0x10, 0x8D, 0x52, 0x62, 0xA1, 0xDB, 0x78, 0x2F, 0x1B, 0xF9, 0x95, 0x7A, 0x24, 0xE1, 0x60, 0xDD,
0x26, 0x9A, 0xBC, 0x3C, 0x3F, 0x2C, 0x98, 0x74, 0x23, 0x7C, 0xF6, 0x1F, 0x91, 0xFE, 0x4C, 0x13,
0xB7, 0xE7, 0x67, 0x0F, 0x53, 0xCC, 0x7E, 0x6B, 0x9B, 0x2E, 0xCF, 0x08, 0x65, 0x92, 0x55, 0x4E,
0x8F, 0x33, 0x38, 0xB1, 0x6C, 0x0D, 0xB0, 0x17, 0x88, 0xEF, 0xEB, 0x0B, 0xD2, 0x61, 0x8C, 0x85,
0xEA, 0xB2, 0x9C, 0xBA, 0x72, 0x47, 0x4A, 0x99, 0xE9, 0x2D, 0x20, 0x0C, 0x05, 0xE4, 0x94, 0x41,
0x4F, 0x3B, 0xDA, 0x96, 0x34, 0xAD, 0xB3, 0xCD, 0x8A, 0xF7, 0x9D, 0xD3, 0x75, 0x89, 0xDF, 0xBF,
0x59, 0x6E, 0x36, 0xE6, 0x14, 0x1C, 0xC8, 0x3E, 0x03, 0xB8, 0xD0, 0x11, 0x7D, 0x8E, 0x90, 0x63,
0x80, 0x81, 0xAF, 0x76, 0x5C, 0x1A, 0x21, 0x28, 0xAC, 0x32, 0x48, 0xFC, 0xC6, 0xBB, 0x0E, 0x1D,
0x18, 0x77, 0x5A, 0x15, 0xCB, 0xC5, 0x64, 0x7B, 0xA8, 0x25, 0x46, 0x73, 0x42, 0xD1, 0x6A, 0x49,
0xD7, 0x8B, 0xC7, 0x06, 0x1E, 0x43, 0xEC, 0xED, 0xFA, 0xF3, 0x31, 0x86, 0x39, 0xFF, 0xAE, 0xB9
    };
 
    unsigned char sbox_inv[256] = { 0 };
 
    for(int i = 0; i < 256; i++)
    {
        unsigned char temp1 = sbox[i];
 
        sbox_inv[temp1] = i;
    }
 
    for(int i = 0; i < 256; i++)
    {
        printf("%X%X, ", sbox_inv[i] / 16, sbox_inv[i] % 16);
    }
 
    return 0;
}

deaes_withsbox.c

#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位
#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] = {
0x31, 0x52, 0x5A, 0xC8, 0x0B, 0xAC, 0xF3, 0x3A, 0x8B, 0x54,
0x27, 0x9B, 0xAB, 0x95, 0xDE, 0x83, 0x60, 0xCB, 0x53, 0x7F,
0xC4, 0xE3, 0x0A, 0x97, 0xE0, 0x29, 0xD5, 0x68, 0xC5, 0xDF,
0xF4, 0x7B, 0xAA, 0xD6, 0x42, 0x78, 0x6C, 0xE9, 0x70, 0x17,
0xD7, 0x37, 0x24, 0x49, 0x75, 0xA9, 0x89, 0x67, 0x03, 0xFA,
0xD9, 0x91, 0xB4, 0x5B, 0xC2, 0x4E, 0x92, 0xFC, 0x46, 0xB1,
0x73, 0x08, 0xC7, 0x74, 0x09, 0xAF, 0xEC, 0xF5, 0x4D, 0x2D,
0xEA, 0xA5, 0xDA, 0xEF, 0xA6, 0x2B, 0x7E, 0x0C, 0x8F, 0xB0,
0x04, 0x06, 0x62, 0x84, 0x15, 0x8E, 0x12, 0x1D, 0x44, 0xC0,
0xE2, 0x38, 0xD4, 0x47, 0x28, 0x45, 0x6E, 0x9D, 0x63, 0xCF,
0xE6, 0x8C, 0x18, 0x82, 0x1B, 0x2C, 0xEE, 0x87, 0x94, 0x10,
0xC1, 0x20, 0x07, 0x4A, 0xA4, 0xEB, 0x77, 0xBC, 0xD3, 0xE1,
0x66, 0x2A, 0x6B, 0xE7, 0x79, 0xCC, 0x86, 0x16, 0xD0, 0xD1,
0x19, 0x55, 0x3C, 0x9F, 0xFB, 0x30, 0x98, 0xBD, 0xB8, 0xF1,
0x9E, 0x61, 0xCD, 0x90, 0xCE, 0x7C, 0x8D, 0x57, 0xAE, 0x6A,
0xB3, 0x3D, 0x76, 0xA7, 0x71, 0x88, 0xA2, 0xBA, 0x4F, 0x3E,
0x40, 0x64, 0x0F, 0x48, 0x21, 0x35, 0x36, 0x2F, 0xE8, 0x14,
0x5D, 0x51, 0xD8, 0xB5, 0xFE, 0xD2, 0x96, 0x93, 0xA1, 0xB6,
0x43, 0x0D, 0x4C, 0x80, 0xC9, 0xFF, 0xA3, 0xDD, 0x72, 0x05,
0x59, 0xBF, 0x0E, 0x26, 0x34, 0x1F, 0x13, 0xE5, 0xDC, 0xF2,
0xC6, 0x50, 0x1E, 0xE4, 0x85, 0xB7, 0x39, 0x8A, 0xCA, 0xED,
0x9C, 0xBB, 0x56, 0x23, 0x1A, 0xF0, 0x32, 0x58, 0xB2, 0x65,
0x33, 0x6F, 0x41, 0xBE, 0x3F, 0x6D, 0x11, 0x00, 0xAD, 0x5F,
0xC3, 0x81, 0x25, 0xA8, 0xA0, 0x9A, 0xF6, 0xF7, 0x5E, 0x99,
0x22, 0x2E, 0x4B, 0xF9, 0x3B, 0x02, 0x7A, 0xB9, 0x5C, 0x69,
0xF8, 0x1C, 0xDB, 0x01, 0x7D, 0xFD
};
 
//逆S盒
unsigned char inv_S[256] =
{
0xe3,0xfd,0xf5,0x30,0x50,0xbd,0x51,0x70,0x3d,0x40,0x16,0x4,0x4d,0xb5,0xc0,0xa2,0x6d,0xe2,0x56,0xc4,0xa9,0x54,0x7f,0x27,0x66,0x82,0xd6,0x68,0xfb,0x57,0xca,0xc3,0x6f,0xa4,0xf0,0xd5,0x2a,0xe8,0xc1,0xa,0x5e,0x19,0x79,0x4b,0x69,0x45,0xf1,0xa7,0x87,0,0xd8,0xdc,0xc2,0xa5,0xa6,0x29,0x5b,0xce,0x7,0xf4,0x84,0x97,0x9f,0xe0,0xa0,0xde,0x22,0xb4,0x58,0x5f,0x3a,0x5d,0xa3,0x2b,0x71,0xf2,0xb6,0x44,0x37,0x9e,0xc9,0xab,0x1,0x12,0x9,0x83,0xd4,0x93,0xd9,0xbe,0x2,0x35,0xf8,0xaa,0xee,0xe5,0x10,0x8d,0x52,0x62,0xa1,0xdb,0x78,0x2f,0x1b,0xf9,0x95,0x7a,0x24,0xe1,0x60,0xdd,0x26,0x9a,0xbc,0x3c,0x3f,0x2c,0x98,0x74,0x23,0x7c,0xf6,0x1f,0x91,0xfe,0x4c,0x13,0xb7,0xe7,0x67,0xf,0x53,0xcc,0x7e,0x6b,0x9b,0x2e,0xcf,0x8,0x65,0x92,0x55,0x4e,0x8f,0x33,0x38,0xb1,0x6c,0xd,0xb0,0x17,0x88,0xef,0xeb,0xb,0xd2,0x61,0x8c,0x85,0xea,0xb2,0x9c,0xba,0x72,0x47,0x4a,0x99,0xe9,0x2d,0x20,0xc,0x5,0xe4,0x94,0x41,0x4f,0x3b,0xda,0x96,0x34,0xad,0xb3,0xcd,0x8a,0xf7,0x9d,0xd3,0x75,0x89,0xdf,0xbf,0x59,0x6e,0x36,0xe6,0x14,0x1c,0xc8,0x3e,0x3,0xb8,0xd0,0x11,0x7d,0x8e,0x90,0x63,0x80,0x81,0xaf,0x76,0x5c,0x1a,0x21,0x28,0xac,0x32,0x48,0xfc,0xc6,0xbb,0xe,0x1d,0x18,0x77,0x5a,0x15,0xcb,0xc5,0x64,0x7b,0xa8,0x25,0x46,0x73,0x42,0xd1,0x6a,0x49,0xd7,0x8b,0xc7,0x6,0x1e,0x43,0xec,0xed,0xfa,0xf3,0x31,0x86,0x39,0xff,0xae,0xb9
};
 
/* 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);
		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);
		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
//pt是原始数据 ct是加密后的数据
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) {
// 把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
	
		// 把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 ct是加密数据 pt是解密后的数据
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) {
// 把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;
}
int main() {
	unsigned char key[17] = "user01_nkctf2024";
	unsigned char encdata[] =
	  {
		0xB0, 0xCC, 0x93, 0xEA, 0xE9, 0x2F, 0xEF, 0x56, 0x99, 0x39,
		0x6E, 0x02, 0x3B, 0x4F, 0x9E, 0x42
	  };
	unsigned char passwd[17] = { 0 };
	aesDecrypt(key, 16, encdata, passwd, 16);
	printf("%s", passwd);//9ee779cd2abcde48
	return 0;
}

ChaCha20_decrypt.py

from Crypto.Cipher import ChaCha20
secret=
nonce=
ciphertext=
cipher=ChaCha20.new(key=secret,nonce=nonce)
plaintext=cipher.decrypt(ciphertext)
print(plaintext)

做题

[羊城杯 2023]Ez加密器

主要流程：需要输入一个密码和flag，密码经Base64换表加密后当作flag的DES加密密钥。

根据Base64的传参可知密钥一共6位数，根据wp可知都是数字。

爆密钥，Base64后解DES，交叉引用可知密文又异或7。

from Crypto.Util.number import *
from Crypto.Cipher import DES
from base64 import *
ciphertext=long_to_bytes(0x0723105D5C12217DCDC3601F5ECB54DA9CCEC2279F1684A13A0D716D17217F4C9EA85FF1A42795731CA3C55D3A4D7BEA)
table='1234567890'
for i1 in table:
    for i2 in table:
        for i3 in table:
            for i4 in table:
                for i5 in table:
                    for i6 in table:
                        key_ = i1+i2+i3+i4+i5+i6
                        string1 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
                        string2 = 'abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ+/'
                        key=b64encode(key_.encode()).decode().translate(str.maketrans(string1,string2)).encode()
                        des = DES.new(key, DES.MODE_ECB)
                        decrypted = des.decrypt(ciphertext)
                        if b'DASCTF' in decrypted:
                            print(key_)
                            print("解密后的结果：", decrypted)