You should look into handycipher: https://www.schneier.com/blog/archives/2014/04/a_new_pencil-an.html https://www.schneier.com/blog/archives/2014/04/a_new_penci

You should look into handycipher: https://www.schneier.com/blog/archives/2014/04/a_new_pencil-an.html https://www.schneier.com/blog/archives/2014/04/a_new_pencil-....