Reply To: !
md5(“upsidedown” || uppercase plaintext of @AndGiggles cipher) = 32069090179049ad3919feb43cd01044
I can’t say I fully (or even mostly) understand the maths of GF(25).
Finite fields are fascinating. The arithmetic of GF(256) is fundamental to the algorithm underlying the advanced encryption standard and I have a few students just learning about that now. It is way beyond GCSE level, but an important part of undergraduate maths and these fields (GF(p^k) for p prime) are fundamental objects in number theory and algebraic geometry. Harry