## Theory

For the AMSCO cipher, we take alternative two letter and one letter occurances, and then fit to a grid with a sequence key. For example, if we have a key of '41325', and we have: 'apessemisticpestexists', then we can layout as:

4 1 3 2 5 --------------- ap e ss e mi s ti c pe s te x is t s

We then read from column 1, and then column 2, and so on. The cipher then becomes 'e ti x e pe t ss c is a ps t em i s s', and so the cipher is 'etixepetsscisapstemiss'