private static byte[] FindKey(byte[] input)
{
var md5 = new MD5CryptoServiceProvider();
var count = 0;
var found = false;
var ffHash = new byte[] { 0xde, 0x03, 0xfe, 0x65, 0xa6, 0x76, 0x5c, 0xaa, 0x8c, 0x91, 0x34, 0x3a, 0xcc, 0x62, 0xcf, 0xfc };
var hashList = new HashEntry[(input.Length / 0x200) + 1];
for (var i = 0; i < (input.Length / 0x200); i++, found = false)
{
var hash = md5.ComputeHash(input, i * 0x200, 0x200);
if (BufferSame(hash, ffHash, 16)) //skip ff blocks...
continue;
// see if we already came up with that hash
for (var j = 0; j < count; j++)
if (BufferSame(hashList[j].Hash, hash, 16))
{
hashList[j].Count++;
found = true;
break;
}
// push new hashlist entry
if (found) continue;
hashList[count] = new HashEntry { Hash = new byte[hash.Length] };
Buffer.BlockCopy(hash, 0, hashList[count].Hash, 0, hash.Length);
hashList[count].Count = 1;
hashList[count].BlockIndex = i;
count++;
}
//Sort by count, Decending
Array.Sort(hashList, (entry1, entry2) => entry2.Count - entry1.Count);
//Check the keys one by one
var foundOffset = 0;
for (var i=0 ; i<hashList.Count() && !found; i++)
{
foundOffset = hashList[i].BlockIndex * 0x200;
if (((input[0x100] ^ input[foundOffset + 0x100]) == 'D') &&
((input[0x101] ^ input[foundOffset + 0x101]) == 'I') &&
((input[0x102] ^ input[foundOffset + 0x102]) == 'S') &&
((input[0x103] ^ input[foundOffset + 0x103]) == 'A'))
found = true;
}
if (!found)
return null; //That's not it
var outbuf = new byte[0x200];
Buffer.BlockCopy(input, foundOffset, outbuf, 0, 0x200);
return outbuf;
}
