* 3 append a NULL byte * 4 serialise and check if prime; if so then done 5 check if any byte value makes it prime when appended. If so, append it, else append

* 3 append a NULL byte * 4 serialise and check if prime; if so then done 5 check if any byte value makes it prime when appended. If so, append it, else append NULL. Repeat until done