dddddddddd teac.h

qq协议分析辅助

#include <windows.h>
#include <string.h>
#include <winsock2.h>

unsigned char decrypted[8], m[8], *crypt_buff, *crypt_buff_pre_8, *outp;
int count, context_start, pos_in_byte, padding, _instrlen;
unsigned char *_key;
unsigned char testdata = (0xAF,0x2B,0x30,0x0C,0x58,0xD8,0x99,0xD7,0x6E,0xEE,0x0F,0x02,0xB3,0xA6,0x0F,0xF9,0x7E,0x82,0x57,0xDF,0xBD,0xF3,0xF5,0xB9,0x0B,0xA8,0x75,0x45,0xE2,0x48,0xF1,0xB8,0xA0,0x99,0x4B,0xF2,0xF0,0x04,0x22,0x38,0x44,0x2D,0x98,0x8C,0x46,0x42,0x6C,0x19,0x25,0xE4,0x8C,0x42,0xA8,0xE0,0xEB,0xF0,0xD8,0x32,0xFA,0xC2,0x16,0x9E,0x2A,0x95,0x62,0xC9,0xE1,0xAF,0xD4,0x40,0x6D,0xA4,0xFF,0x6A,0xA6,0xC9,0xE6,0xAE,0x35,0x16);
unsigned char testkey = (01,01,01,01,01,01,01,01,01,01,01,01,01,01,01,01);
unsigned char testout[80];
int testoutbytes;

/*****************************************************************************/
void qq_encipher(unsigned long *const v, const unsigned long *const k, unsigned long *const w)
{
register unsigned long y = ntohl(v[0]), z = ntohl(v[1]), a = ntohl(k[0]), b = ntohl(k[1]), c = ntohl(k[2]), d = ntohl(k[3]), n = 0x10, sum = 0, delta = 0x9E3779B9; /* 0x9E3779B9 - 0x100000000 = -0x61C88647 */

while (n-- > 0) {
sum += delta;
y += ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
z += ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
} // while

w[0] = htonl(y);
w[1] = htonl(z);
} // qq_enciper

/*****************************************************************************/
void qq_decipher(unsigned long *const v, const unsigned long *const k, unsigned long *const w)
{
register unsigned long y = ntohl(v[0]), z = ntohl(v[1]), a = ntohl(k[0]), b = ntohl(k[1]), c = ntohl(k[2]), d = ntohl(k[3]), n = 0x10, sum = 0xE3779B90, // why this ? must be related with n value
delta = 0x9E3779B9;

/* sum = delta<<5, in general sum = delta * n */
while (n-- > 0) {
z -= ((y << 4) + c) ^ (y + sum) ^ ((y >> 5) + d);
y -= ((z << 4) + a) ^ (z + sum) ^ ((z >> 5) + b);
sum -= delta;
}

w[0] = htonl(y);
w[1] = htonl(z);
} // qq_decipher

/********************************************************************
* [decrypt part]
* return 0 if failed, otherwise return 1
********************************************************************/
int decrypt_every_8_byte(void) {
for (pos_in_byte = 0; pos_in_byte < 8; pos_in_byte++) {
if (context_start + pos_in_byte >= _instrlen)
return 1;
decrypted[pos_in_byte] ^= crypt_buff[pos_in_byte];
}
qq_decipher((unsigned long *) decrypted, (unsigned long *) _key, (unsigned long *) decrypted);

context_start += 8;
crypt_buff += 8;
pos_in_byte = 0;
return 1;
} // decrypt_every_8_byte

int qq_decrypt(unsigned char *instr, int instrlen, unsigned char *key, unsigned char *outstr, int *outstrlen_ptr)
{
_instrlen = instrlen;
_key = key;
// at least 16 bytes and %8 == 0
if ((instrlen % 8) || (instrlen < 16))
return 0;
// get information from header
qq_decipher((unsigned long *) instr, (unsigned long *) key, (unsigned long *) decrypted);
pos_in_byte = decrypted[0] & 0x7;
count = instrlen - pos_in_byte - 10; // this is the plaintext length
// return if outstr buffer is not large enought or error plaintext length
if (*outstrlen_ptr < count || count < 0)
return 0;

memset(m, 0, 8);
crypt_buff_pre_8 = m;
*outstrlen_ptr = count; // everything is ok! set return string length

crypt_buff = instr + 8; // address of real data start
context_start = 8; // context is at the second 8 byte
pos_in_byte++; // start of paddng stuff

padding = 1; // at least one in header
while (padding <= 2) { // there are 2 byte padding stuff in header
if (pos_in_byte < 8) { // bypass the padding stuff, none sense data
pos_in_byte++;
padding++;
}
if (pos_in_byte == 8) {
crypt_buff_pre_8 = instr;
if (!decrypt_every_8_byte())
return 0;
}
} // while

outp = outstr;
while (count != 0) {
if (pos_in_byte < 8) {
*outp = crypt_buff_pre_8[pos_in_byte] ^ decrypted[pos_in_byte];
outp++;
count--;
pos_in_byte++;
}
if (pos_in_byte == 8) {
crypt_buff_pre_8 = crypt_buff - 8;
if (!decrypt_every_8_byte())
return 0;
}
} // while

for (padding = 1; padding < 8; padding++) {
if (pos_in_byte < 8) {
if (crypt_buff_pre_8[pos_in_byte] ^ decrypted[pos_in_byte])
return 0;
pos_in_byte++;
}
if (pos_in_byte == 8) {
crypt_buff_pre_8 = crypt_buff;
if (!decrypt_every_8_byte())
return 0;
}
} // for
return 1;
} // qq_decrypt

/*
int main()
{
int dwre;

dwre=qq_decrypt((unsigned char *)testdata,80,(unsigned char *)testkey,(unsigned char *)testout,(int *)testoutbytes);
return 0;
}
*/