[MoeCTF 2022]ezTea

 我打开出现乱码注释，不过不影响解题

#include 
#include void encrypt (uint32_t* v, uint32_t* k) {                       // 涓昏鍔犲瘑鍑芥暟锛岃瘯鐫€鎼炲畾瀹?uint32_t v0 = v[0], v1 = v[1], sum = 0;uint32_t delta = 0xd33b470;for (int i = 0; i < 32; i++) {sum += delta;v0 += ((v1<<4) + k[0]) ^ (v1 + sum) ^ ((v1>>5) + k[1]);v1 += ((v0<<4) + k[2]) ^ (v0 + sum) ^ ((v0>>5) + k[3]);}v[0] = v0;v[1] = v1;
}int main() {uint32_t k[4] = {1, 2, 3, 4};int8_t input[33] = {0};scanf("%32s", input);for (int i = 0; i < 32; i+=8) {uint32_t v[2] = {*(uint32_t *)&input[i], *(uint32_t *)&input[i+4]};encrypt(v, k);for (int j = 0; j < 2; j++) {                           // 杩欎竴娈典富瑕佹槸鎶?v 鎸夊崟瀛楄妭杈撳嚭锛屽彟澶栧彲浠ヤ簡瑙ｄ竴涓?鈥滃ぇ灏忕搴忊€?鍦ㄨ繖棰樻槸濡備綍浣撶幇鐨?for (int k = 0; k < 4; k++) {printf("%#x, ", v[j] & 0xff);v[j] >>= 8;}}}return 0;
}

从另一个文件中得到运行结果：0x17, 0x65, 0x54, 0x89, 0xed, 0x65, 0x46, 0x32, 0x3d, 0x58, 0xa9, 0xfd, 0xe2, 0x5e, 0x61, 0x97, 0xe4, 0x60, 0xf1, 0x91, 0x73, 0xe9, 0xe9, 0xa2, 0x59, 0xcb, 0x9a, 0x99, 0xec, 0xb1, 0xe1, 0x7d

#include 
#include void decrypt(uint32_t* v, uint32_t* k) 
{uint32_t v0 = v[0], v1 = v[1], sum = 0xd33b470*32;uint32_t delta = 0xd33b470;for (int i = 0; i < 32; i++) {v1 -= ((v0 << 4) + k[2]) ^ (v0 + sum) ^ ((v0 >> 5) + k[3]);v0 -= ((v1 << 4) + k[0]) ^ (v1 + sum) ^ ((v1 >> 5) + k[1]);sum -= delta;}v[0] = v0;v[1] = v1;
}int main() 
{uint32_t k[4] = { 1, 2, 3, 4 };//uint32_t——4字节，uint8_t——1字节int8_t input[] = { 0x17, 0x65, 0x54, 0x89, 0xed, 0x65, 0x46, 0x32, 0x3d, 0x58, 0xa9, 0xfd, 0xe2, 0x5e,0x61, 0x97, 0xe4, 0x60, 0xf1, 0x91, 0x73, 0xe9, 0xe9, 0xa2, 0x59, 0xcb, 0x9a, 0x99,0xec, 0xb1, 0xe1, 0x7d };for (int i = 0; i < 32; i += 8) {uint32_t v[2] = { *(uint32_t*)&input[i], *(uint32_t*)&input[i + 4] };//1字节强制转换为4字节decrypt(v, k);//加密for (int j = 0; j < 2; j++)//一字节一字节打印出来{for (int k = 0; k < 4; k++) {printf("%c", v[j] & 0xff);v[j] >>= 8;}}}return 0;
}

 moectf{Th3_TEA_!S_s0_t4s7y~~!!!}

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