1997

这个题是一个魔改的AES，具体逻辑很清楚，甚至还有符号表

但是中间这里没想到有什么方法可以逆向，所以直接爆破了

列混淆：

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for ( i = 0; i <= 0xFu; i += 4 )
{
  t = tmp[i + 2] ^ tmp[i + 1] ^ tmp[i] ^ tmp[i + 3];
  ciphertext[i] = t ^ tmp[i] ^ mul2(tmp[i] ^ tmp[i + 1]);
  ciphertext[i + 1] = t ^ tmp[i + 1] ^ mul2(tmp[i + 1] ^ tmp[i + 2]);
  ciphertext[i + 2] = t ^ tmp[i + 2] ^ mul2(tmp[i + 2] ^ tmp[i + 3]);
  ciphertext[i + 3] = t ^ tmp[i + 3] ^ mul2(tmp[i + 3] ^ tmp[i]);
}
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uint8_t __cdecl mul2(uint8_t a)
{
  if ( (a & 0x80u) == 0 )
    return 2 * a;
  else
    return (2 * a) ^ 0x1B;
}

tmp是输入值，ciphertext是输出值，这里已知ciphertext，想求tmp，想了一下相互的关系，发现ciphertext相互异或就是t，所以我尝试爆破tmp的值，由于每个tmp是8位，每两个进行一次检查，所以相当于是爆16位，位数比较小

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void cToTmp(uint8_t* tmp, uint8_t* c) {
	for (int i = 0; i <= 0xFu; i += 4) {
		uint8_t t = c[i + 2] ^ c[i + 1] ^ c[i] ^ c[i + 3];
		int j = 0;
		for (uint16_t t0 = 0; t0 <= 256; t0++)
		{
			for (uint16_t t1 = 0; t1 <= 256; t1++)
			{
				if (c[i] == (t ^ t0 ^ mul2(t0 ^ t1)))
				{
					for (uint16_t t2 = 0; t2 <= 256; t2++)
					{
						if (c[i + 1] == (t ^ t1 ^ mul2(t2 ^ t1)))
						{
							for (uint16_t t3 = 0; t3 <= 256; t3++)
							{
								if (c[i + 2] == (t ^ t2 ^ mul2(t2 ^ t3)))
								{
									if (c[i + 3] == (t ^ t3 ^ mul2(t0 ^ t3)))
									{
										tmp[i] = t0;
										tmp[i + 1] = t1;
										tmp[i + 2] = t2;
										tmp[i + 3] = t3;
										//printf("%x %x %x %x\n", tmp[i], tmp[i + 1], tmp[i + 2], tmp[i + 3]);
										goto next;
									}
								}
							}
						}
					}
				}
			}
		}
	next:;

	}
}

这个测试下来确实可以得到一开始的答案，所以最后

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#include<iostream>
#include <Windows.h>
#include <string>
using namespace std;
unsigned char SBOX[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 INV_SBOX[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
};

void __cdecl shift_rows(uint8_t* state)
{
	uint8_t temp; // [rsp+Fh] [rbp-1h]
	uint8_t tempa; // [rsp+Fh] [rbp-1h]
	uint8_t tempb; // [rsp+Fh] [rbp-1h]
	uint8_t tempc; // [rsp+Fh] [rbp-1h]

	temp = state[12];
	state[12] = state[8];
	state[8] = state[4];
	state[4] = *state;
	*state = temp;
	tempa = state[1];
	state[1] = state[9];
	state[9] = tempa;
	tempb = state[5];
	state[5] = state[13];
	state[13] = tempb;
	tempc = state[2];
	state[2] = state[6];
	state[6] = state[10];
	state[10] = state[14];
	state[14] = tempc;
}
void __cdecl inv_shiftrows( uint8_t* state)
{
	uint8_t temp; // [rsp+Fh] [rbp-1h]
	uint8_t tempa; // [rsp+Fh] [rbp-1h]
	uint8_t tempb; // [rsp+Fh] [rbp-1h]
	uint8_t tempc; // [rsp+Fh] [rbp-1h]

	//temp = state[12];
	//state[12] = state[8];
	//state[8] = state[4];
	//state[4] = *state;
	//*state = temp;

	temp = *state;
	*state = state[4];
	state[4] = state[8];
	state[8] = state[12];
	state[12] = temp;


	//tempa = state[1];
	//state[1] = state[9];
	//state[9] = tempa;

	tempa = state[9];
	state[9] = state[1];
	state[1] = tempa;


	//tempb = state[5];
	//state[5] = state[13];
	//state[13] = tempb;

	tempb = state[13];
	state[13] = state[5];
	state[5] = tempb;

	//tempc = state[2];
	//state[2] = state[6];
	//state[6] = state[10];
	//state[10] = state[14];
	//state[14] = tempc;

	tempc = state[14];
	state[14] = state[10];
	state[10] = state[6];
	state[6] = state[2];
	state[2] = tempc;

}

uint8_t __cdecl mul2(uint8_t a)
{
	if ((a & 0x80u) == 0)
		return 2 * a;
	else
		return (2 * a) ^ 0x1B;
}

static void aes_encrypt_128(BYTE* roundkeys, BYTE* m, BYTE* c)
{
	const uint8_t* mid; // rax
	const uint8_t* v4; // rax
	const uint8_t* v5; // rax
	uint8_t tmp[16]; // [rsp+20h] [rbp-20h] BYREF
	uint8_t t; // [rsp+3Dh] [rbp-3h]
	uint8_t j; // [rsp+3Eh] [rbp-2h]
	uint8_t i; // [rsp+3Fh] [rbp-1h]

	for (i = 0; i <= 0xFu; ++i)
	{
		mid = roundkeys++;
		c[i] = *mid ^ m[i];
	}
	for (j = 1; j <= 9u; ++j)
	{
		for (i = 0; i <= 0xFu; ++i)
			tmp[i] = INV_SBOX[c[i]];
		shift_rows(tmp);
		for (i = 0; i <= 0xFu; i += 4)
		{
			t = tmp[i + 2] ^ tmp[i + 1] ^ tmp[i] ^ tmp[i + 3];
			c[i] = t ^ tmp[i] ^ mul2(tmp[i] ^ tmp[i + 1]);
			c[i + 1] = t ^ tmp[i + 1] ^ mul2(tmp[i + 1] ^ tmp[i + 2]);
			c[i + 2] = t ^ tmp[i + 2] ^ mul2(tmp[i + 2] ^ tmp[i + 3]);
			c[i + 3] = t ^ tmp[i + 3] ^ mul2(tmp[i + 3] ^ tmp[i]);
		}
		for (i = 0; i <= 0xFu; ++i)
		{
			v4 = roundkeys++;
			c[i] ^= *v4;
		}
	}
	for (i = 0; i <= 0xFu; ++i)
		c[i] = INV_SBOX[c[i]];
	shift_rows(c);

	for (i = 0; i <= 0xFu; ++i)
	{
		v5 = roundkeys++;
		c[i] ^= *v5;
	}
}


void cToTmp(uint8_t* tmp, uint8_t* c) {
	for (int i = 0; i <= 0xFu; i += 4) {
		uint8_t t = c[i + 2] ^ c[i + 1] ^ c[i] ^ c[i + 3];
		int j = 0;
		for (uint16_t t0 = 0; t0 <= 256; t0++)
		{
			for (uint16_t t1 = 0; t1 <= 256; t1++)
			{
				if (c[i] == (t ^ t0 ^ mul2(t0 ^ t1)))
				{
					for (uint16_t t2 = 0; t2 <= 256; t2++)
					{
						if (c[i + 1] == (t ^ t1 ^ mul2(t2 ^ t1)))
						{
							for (uint16_t t3 = 0; t3 <= 256; t3++)
							{
								if (c[i + 2] == (t ^ t2 ^ mul2(t2 ^ t3)))
								{
									if (c[i + 3] == (t ^ t3 ^ mul2(t0 ^ t3)))
									{
										tmp[i] = t0;
										tmp[i + 1] = t1;
										tmp[i + 2] = t2;
										tmp[i + 3] = t3;
										//printf("%x %x %x %x\n", tmp[i], tmp[i + 1], tmp[i + 2], tmp[i + 3]);
										goto next;
									}
								}
							}
						}
					}
				}
			}
		}
	next:;

	}
}


void aes_decrypt_128(BYTE* roundkeys, BYTE* c, BYTE* m)
{
	uint8_t tmp[16]; // [rsp+20h] [rbp-20h] BYREF

	BYTE* u = 0;
	roundkeys = &roundkeys[175];
	for (int i = 0xf; i >= 0; --i)
	{
		u = roundkeys--;
		m[i] = *u ^ c[i];
	}
	for (int j = 9; j >= 1; --j)
	{
		inv_shiftrows(m);
		for (int i = 0; i <= 0xF; ++i)
			m[i] = SBOX[m[i]];
		for (int i = 0xf; i >= 0; --i)
		{
			u = roundkeys--;
			m[i] ^= *u;
		}
		cToTmp(tmp, m);
		for (int i = 0; i < 0x10; ++i)
		{
			m[i] = tmp[i];
		}
	}
	inv_shiftrows(m);
	for (int i = 0; i <= 0xF; ++i)
		m[i] = SBOX[m[i]];
	for (int i = 0xf; i >= 0; --i)
	{
		u = roundkeys--;
		m[i] ^= *u;
	}
}

static void encMain(BYTE* roundKey, BYTE* m)
{
	//auto part1 = reinterpret_cast<BYTE*>(const_cast<char*>(m.substr(0, m.length() / 2).c_str()));
	//auto part2 = reinterpret_cast<BYTE*>(const_cast<char*>(m.substr(m.length() / 2).c_str()));
	/*BYTE* part1 = const_cast<BYTE*>(m.data());*/

	BYTE c[33] = {};
	aes_encrypt_128(roundKey, m, c);
	aes_encrypt_128(roundKey, m + 16, &c[16]);
	for (int i = 0; i < 32; i++)
	{
		printf("0x%x,", c[i]);
	}
}


void decMain(BYTE* roundKey, BYTE* c)
{
	BYTE m[33] = {};
	aes_decrypt_128(roundKey, c, m);
	aes_decrypt_128(roundKey, &c[16], m + 16);
	for (int i = 0; i < 32; i++)
	{
		printf("0x%x,", m[i]);
	}
	std::cout << endl;
	printf("%s", m);
}

int main(int argc, char* argv[])
{
	BYTE m[] = "11111111111111111111111111111111\0";
	unsigned char rkey[179] = {
	0x57, 0x65, 0x6C, 0x63, 0x6F, 0x6D, 0x65, 0x5F, 0x74, 0x6F, 0x5F, 0x63, 0x74, 0x66, 0x21, 0x21,
	0x65, 0x98, 0x91, 0xF1, 0x0A, 0xF5, 0xF4, 0xAE, 0x7E, 0x9A, 0xAB, 0xCD, 0x0A, 0xFC, 0x8A, 0xEC,
	0xD7, 0xE6, 0x5F, 0x96, 0xDD, 0x13, 0xAB, 0x38, 0xA3, 0x89, 0x00, 0xF5, 0xA9, 0x75, 0x8A, 0x19,
	0x4E, 0x98, 0x8B, 0x45, 0x93, 0x8B, 0x20, 0x7D, 0x30, 0x02, 0x20, 0x88, 0x99, 0x77, 0xAA, 0x91,
	0xB3, 0x34, 0x0A, 0xAB, 0x20, 0xBF, 0x2A, 0xD6, 0x10, 0xBD, 0x0A, 0x5E, 0x89, 0xCA, 0xA0, 0xCF,
	0xD7, 0xD4, 0x80, 0x0C, 0xF7, 0x6B, 0xAA, 0xDA, 0xE7, 0xD6, 0xA0, 0x84, 0x6E, 0x1C, 0x00, 0x4B,
	0x6B, 0xB7, 0x33, 0x93, 0x9C, 0xDC, 0x99, 0x49, 0x7B, 0x0A, 0x39, 0xCD, 0x15, 0x16, 0x39, 0x86,
	0x6C, 0xA5, 0x77, 0xCA, 0xF0, 0x79, 0xEE, 0x83, 0x8B, 0x73, 0xD7, 0x4E, 0x9E, 0x65, 0xEE, 0xC8,
	0xA1, 0x8D, 0x9F, 0xC1, 0x51, 0xF4, 0x71, 0x42, 0xDA, 0x87, 0xA6, 0x0C, 0x44, 0xE2, 0x48, 0xC4,
	0x22, 0xDF, 0x83, 0xDA, 0x73, 0x2B, 0xF2, 0x98, 0xA9, 0xAC, 0x54, 0x94, 0xED, 0x4E, 0x1C, 0x50,
	0x3B, 0x43, 0xD0, 0x8F, 0x48, 0x68, 0x22, 0x17, 0xE1, 0xC4, 0x76, 0x83, 0x0C, 0x8A, 0x6A, 0xD3,
	0x40, 0x15, 0x40
	};
	//encMain(rkey, m);
	unsigned int c[8] = {
	0x768E076C, 0x8A2F31A6, 0xE452B98D, 0xAA000D64, 0x48802D4B, 0xEC290C73, 0x17F0FFC3, 0x2785A657
	};
	decMain(rkey, reinterpret_cast<BYTE*>(c));
}