using generated credentials in skype

[vinnitu]

~/.SkyLogin/user/Credentials and ~/.Skype/username/config.xml: are not the same? I see that first is in binary format and second in hex, but only first 16 bytes are equal. So I can't to understand can I use first (after conversion to hex-stringify) instead of encond? Maybe I miss something?

[leecher1337]

IIrc., Credentials in Skype for Linux config.xml are encoded with FastTrak cipher:

void FastTrack_decode(unsigned char *buf, unsigned int iLen)
{
  unsigned int crc;
  unsigned int i;

  if ( iLen >= 16 )
  {
    crc = _crc32(buf, 16);
    for ( i = 16; i < iLen; i++ )
    {
      crc = 69069 * crc + 17009;
      buf[i] ^= (crc >> 24);
    }
  }
}

[vinnitu]

So yes or no?

[leecher1337]

Yes, but FastTrack "encrypted", so decrypt them first before checking.

[vinnitu]

int Credentials_Save(Memory_U creds, char *pszUser)
{
    FILE *fp;
    int iRet = 0;
    char  szKey[PATH_MAX];

    sprintf (szKey, "%s/.SkyLogin/", getConfigDir());
    mkdir(szKey, 0755);
    strcat (szKey, pszUser);
    mkdir(szKey, 0755);
    strcat (szKey, "/Credentials");
    if (fp = fopen (szKey, "w"))
    {

        FastTrack_decode(creds.Memory, creds.MsZ); // <------------- something like this?
        // TODO: hexify

        iRet = fwrite(creds.Memory, creds.MsZ, 1, fp);
        fclose(fp);
    }
    return iRet;
}

[leecher1337]

More like the other way round.. Read Credentials3 from Skype .xml file, unhexify it with sscanf and then FastTrack_decode the value to read Skype credentials.
Or what are you planning to do?

[vinnitu]

I need create part of file config.xml tag with pair (login, password)

[leecher1337]

In theory, this should work then, I don't have Skype for Linux to test, just try it out...

[vinnitu]

size of credentials skylogin is 404 bytes (808 in hex),
but size of hex credentials of Credentials3 in skype (linux) is 1212 (606 in binary)

[vinnitu]

maybe we need increase size of rsa key? 512 -> 1024?