xtea decryption

[AxxA]

hi, i need xtea enc/dec source.
i belive there is something called tibiaapi, but i have NO IDEA what is it for.
i just need to decrypt incoming packets go get logical data, and then encrypt them.

thx.

[Melody]

http://en.wikipedia.org/wiki/XTEA

#include <stdint.h>
 
void encipher(unsigned int num_rounds, uint32_t v[2], uint32_t const k[4]) {
    unsigned int i;
    uint32_t v0=v[0], v1=v[1], sum=0, delta=0x9E3779B9;
    for (i=0; i < num_rounds; i++) {
        v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
        sum += delta;
        v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
    }
    v[0]=v0; v[1]=v1;
}
 
void decipher(unsigned int num_rounds, uint32_t v[2], uint32_t const k[4]) {
    unsigned int i;
    uint32_t v0=v[0], v1=v[1], delta=0x9E3779B9, sum=delta*num_rounds;
    for (i=0; i < num_rounds; i++) {
        v1 −= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
        sum −= delta;
        v0 −= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
    }
    v[0]=v0; v[1]=v1;
}

TibiaAPI is a framework for tibia built by certain TP members, makes things quite simple.
TibiaAPI in Google Code

PS. There's also some libraries for de/encrypting around these forums.

[AxxA]

cmon dont just copy and paste codes from wiki, wich i dont understand.
decrypt(in, out, size, key)
plz in this format

[AxxA]

as for tibiaapi from your link, its either encrypted or there is smething wrong with it (dll no exports). ill keep my distance from it.

i just need simple function to decrypt XTEA, cryptofuck isnt my best side, belive me i cant underastand it yet.

[Yaboomaster]

cmon dont just copy and paste codes from wiki, wich i dont understand.
decrypt(in, out, size, key)
plz in this format

plz dont act like a noob and dont ask about source codes...
If u dont understand it u should learn more...

[AxxA]

#include <windows.h>
char pp[]={0xcc, 0x00, 0x5a, 0x61, 0xee, 0xe4, 0x5f, 0xb0, 0x27, 0xc1, 0x46, 0x7d, 0xc3, 0x84, 0x90, 0x3f, 0x58, 0x7f, 0xb1, 0x69, 0x6c, 0x27, 0x3c, 0xca, 0xd2, 0xd1, 0x8d, 0xe6, 0x8d, 0x72, 0x22, 0x8d, 0x98, 0x6d, 0x33, 0xfb, 0x2e, 0x03, 0x0a, 0x83, 0x0e, 0x8d, 0x45, 0x86, 0x51, 0x59, 0xaf, 0x92, 0xe5, 0x1c, 0x80, 0xc6, 0xa5, 0xa8, 0x4f, 0x52, 0x18, 0xa3, 0xaa, 0x77, 0xa3, 0x00, 0x9b, 0xbe, 0x43, 0x75, 0x41, 0xc9, 0x96, 0xe6, 0x3d, 0x8e, 0x49, 0xc6, 0xff, 0x4d, 0xc5, 0xc6, 0x6f, 0xe6, 0x0a, 0xa2, 0xde, 0x50, 0xdb, 0x34, 0x13, 0x77, 0x87, 0x32, 0x61, 0x3f, 0xdf, 0x2b, 0xcf, 0xbb, 0x8a, 0xe8, 0x66, 0x04, 0x99, 0x97, 0xb8, 0x49, 0x81, 0x87, 0x0c, 0x12, 0xca, 0x17, 0x1f, 0x02, 0xf5, 0xe0, 0x71, 0xc3, 0xaf, 0x54, 0x80, 0x8b, 0x3e, 0x45, 0x75, 0x70, 0xc9, 0xba, 0x29, 0x28, 0xe7, 0xb6, 0xab, 0x0a, 0xa2, 0xf4, 0x18, 0xdf, 0x2c, 0x11, 0x5d, 0x97, 0x3e, 0x34, 0x15, 0x3f, 0xac, 0xea, 0xd0, 0x21, 0x8f, 0x0b, 0xed, 0xae, 0xfd, 0xe9, 0xd7, 0x53, 0x3b, 0x58, 0x07, 0xff, 0x6a, 0x44, 0x07, 0xb1, 0x19, 0xce, 0x41, 0xd9, 0x54, 0xc2, 0x43, 0x91, 0x32, 0x4f, 0x75, 0x31, 0x0b, 0xc4, 0x56, 0xac, 0x94, 0x8f, 0x8b, 0x92, 0x8b, 0x68, 0x60, 0xc1, 0xbf, 0xd6, 0x43, 0x7b, 0xe5, 0x36, 0x81, 0x26, 0xd8, 0x8c, 0xd8, 0x2d, 0x95, 0xc2, 0x5b, 0x85, 0x87, 0xac};
char xGameKey[16];
unsigned char* getDecryptedCopy(const char * buf, int len){
unsigned char *data = (unsigned char*)malloc(sizeof(char)*(len+1));
memcpy(data, buf, len);
data[len]=0;
int iPos = 0;
while( iPos < len-1 )
{
DecipherTibia(data+iPos, xGameKey);
int iLength = data[iPos+1] << 8 | data[iPos];
iPos += iLength+2;
}
return data;
}

int DecipherTibia(void* p1, void* p2 ){
char* data = (char*)p1;
char* key = (char*)p2;
unsigned char i1 = *(char*)p1;
unsigned char i2 = *(((char*)p1)+1);
unsigned int iCount = i1+i2*256;
data += 2;
int i;
for(i=0; i < iCount/8; i++ )
{
tean( (long*)data, (long*)key, -32 );
data +=8;
}
return iCount;
}



int tean(long *v, long *k, long N){
unsigned long y = v[0],
z = v[1],
DELTA = 0x9e3779b9,
limit,
sum;

if (N > 0) /* coding */
{ limit = DELTA * N;
sum = 0;

while (sum != limit)
{ y += (z << 4 ^ z >> 5) + z ^ sum + k[sum & 3];
sum += DELTA;
z += (y << 4 ^ y >> 5) + y ^ sum + k[sum >> 11 & 3];
}
}
else /* decoding */
{ sum = DELTA * (-N);

while (sum)
{ z -= (y << 4 ^ y >> 5) + y ^ sum + k[sum >> 11 & 3];
sum -= DELTA;
y -= (z << 4 ^ z >> 5) + z ^ sum + k[sum & 3];
}
}

v[0] = y;
v[1] = z;
return;
}

int main(){
int wnd;
int proc;
int i;
char *a;
unsigned int d;
a = getDecryptedCopy(pp, sizeof(pp));
wnd = FindWindowA("TibiaClient", 0);
if(wnd != 0){
GetWindowThreadProcessId(wnd, &proc);
wnd = OpenProcess(PROCESS_VM_READ, 0, proc);
ReadProcessMemory(wnd, 0x78BF34, xGameKey, 16, 0);
for(i=0;i<sizeof(pp);i++){
d = *(int*)(&a[i]);
d <<= 24;
d >>= 24;
printf("%c", d);
}



}
return 0;
}

so tell me why it doesnt work.
address is from 8.5. i cant say, maybe you?
im getting wrong packet (this is npc saying something to me)

[Jesper_Kladden]

Why do you declare "wnd" two times O.o?

[Snowak]

XTea key changes everytime you login. In your code you're trying to decrypt a packet with a different key than was used to encrypt it.

@Jesper:
owned... lol
you made me speechless for few seconds
first wnd holds window's handle and later it holds handle to the process

[AxxA]

i censored variable names to post it for public.
and packet is captured in same session, i know xtea key change.

why i cant correctly decode it? wrong address? or smth?

[AxxA]

#include <windows.h>
int encipher(unsigned int num_rounds, unsigned int v[2], char *k) {
unsigned int i, v0, v1, delta, sum;
v0=v[0];
v1=v[1];
delta=0x9E3779B9;
sum=delta*num_rounds;



for (i=0; i < num_rounds; i++) {
v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
sum += delta;
v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
}
v[0]=v0;
v[1]=v1;


return 0;
}
 
int decipher(unsigned int num_rounds, unsigned int v[2], char *k) {
unsigned int i, v0, v1, delta, sum;
v0=v[0];
v1=v[1];
delta=0x9E3779B9;
sum=delta*num_rounds;

for (i=0; i < num_rounds; i++) {
v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum>>11) & 3]);
sum -= delta;
v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
}
v[0]=v0;
v[1]=v1;


return 0;
}


int main(){
unsigned char key[16];
unsigned char data[8];
memset(data, 'A', sizeof(data));
memset(key, 'i', sizeof(key));
puts(data);
encipher(32, &data, key);
puts(data);

puts("\r\n\r\n\r\n");
decipher(32, &data, key);
puts(data);
return 0;
}

thats a problem. why it also doesnt work?!