As for how the Hill Cipher works:
One takes an reversible (has an inverse Matrix, which is a Matrix in relation to the first Matrix where Matrix A * Matrix B = Matrix B * Matrix A) n*n Matrix – this is the key. One then splits the text into groups of letters size n, and then writes each of these groups of letters as a Matrix. From there, one multiplies each Matrix of n letters by the key, modulus 26, to create a new set of Matrices. These Matrices are then converted back into letters, which are then strung together to create the ciphertext.
For decrypting the ciphertext with the key, one works out the inverse Matrix to the key Matrix, taking modular arithmetic into account (this is the bit I struggle to get my head around, because of things like 1/3 = 9 if you’re multiplying in mod 26), and then encrypt the cipher text with the inverse Matrix, as described above to get the plaintext!
ADuptheTotal1 (great name by the way!) I don’t remember a 2*2 being used in 8B? As I understand the set of letters obtained from the numbers was encrypted with monoalphabetic substitution?
Ooh, and just whilst writing this I’ve had a thought, imagine how mean it would be if 8B was like a 12*12 Hill Cipher!
