packet decryption?

[4C1D^]

soo, ich wuerde gerne bissl mit den wow-packets rumspielen.
allerdings hab ich keine ahnung, wie ich die decrypten soll. weiss da wer was?
Ping

[Hydrox]

K.a. obs noch akutell ist aber:

Packet decryption:

BYTE *DecryptPacket(BYTE *Packet, DWORD len) {
   BYTE KeyIndex, curKey, lastByte;
   DWORD i;

   KeyIndex = *(CryptInfo + 0x115);

   lastByte = 0;

   for(i = 0; i < len; i++) {      //return the key to the initial state
     KeyIndex--;
       if(KeyIndex == 0xFF)         //-1, bytes are unsigned
        KeyIndex = 39;
   }

   for(i = 0; i < len; i++) {
  curKey   = *(*(BYTE **)(CryptInfo + 0x11C) + KeyIndex);
  tmp = *(Packet + i);
  *(Packet + i) = (*(Packet + i ) - lastByte)) ^ curKey;
  lastByte = tmp;
   }

   return Packet;
}

Crypt Info

typedef struct WoWKeyIndex {
   BYTE Index;
   BYTE LastByte;
   BYTE CryptLen;     
} WoWKeyIndex;

typedef struct WoWCryptInfo {
   BYTE IsCrypted;               
   WoWKeyIndex SendKey;
   WoWKeyIndex RecvKey;
   BYTE KeyLen;
   char *Key;
} WoWCryptInfo;

typedef struct WoWClientOP {
   WORD Size;
   DWORD Code;
   BYTE Data[MAX_PACKET_LEN];
} WoWClientOP;

typedef struct WoWServerOP {
   WORD Size;
   WORD Code;
   BYTE Data[MAX_PACKET_LEN];
} WoWServerOP;

Ansonsten kannst du dich mit WoW Emulatoren befassen.

Originally Posted by AlexM

And yes, you can "sniff" the encryption in the packets. That's basically how emulated servers are able to encrypt/decrypt packets. Someone went through with a disassembler and/or debugger, figured out the encryption in ASM, and finally converted it to C/C++/etc.