CRYPTANALYSIS OF KRYHA MACHINE.

Abstract

In the early part of this century, a mechanical ciphering machine was invented by a German engineer, Alexander von Kryha of Berlin. The standard Kryha machine contains two basic components; the first, a cipher disk consists of two rings. On the outer (fixed) ring the letters A, B, . . . , Z of the (plaintext) alphabet are written, while on the inner (moveable) ring a substitution pi (A), pi (B), . . . , pi (Z) of the letters of the (ciphertext) alphabet is recorded twice. The cipher wheel is the second component; it has a number of pins kappa equals (k//0, k//1, . . . , k//s// minus //1) located at stop points and controls the (counterclockwise) rotation of the inner ring. The letters of the ciphertext alphabet are on tabs inserted into 52 slots on the inner ring, so that the permutation pi is one component of the key. An example of the cryptanalysis of a Kryha machine is presented.