[Tutor] Iterate over letters in a word

[Danny Yoo]

> Yes - at the moment this is just a way for me to begin to get my head
> around how cryptography works from anabsolutely ludicrously basic
> position.  This all started because I couldn't get my head around the
> difference between an encryption algorithm and the key.  I thought that
> by writing my own, I would work it out!

Hi Steve,

Yup; it really has to do with numbers.  Once we manage that leap, then
it's just a matter of writing functions that transform numbers to other
numbers.

When you want to get more in depth, you may find:

    http://mitpress.mit.edu/sicp/psets/ps3/readme.html

useful; it's a fun homework assignment on the RSA cryptosystem.  The
support functions are in Scheme, but converting it to Python isn't too
bad.


Best of wishes!