1
vote
2answers
258 views

What are requirements for this grille?

I'm trying to program a Cardan grille, but I can't find requirements for grille. In my case, grille is square matrix A with $N$ x $N$ size, and elements are $0$ or $1$ (where $1$ means that it is ...
1
vote
1answer
248 views

What is total key space in transposition algorithms

How we can measure key space in transposition algorithms? Should we specify the method, like rail fence?
3
votes
1answer
1k views

Obtaining the key length from the ciphertext of an auto-encipher

I'm revising for a cryptography exam at the moment and I'm having some problems with a question. The question looks for the key length of a cipher given that the word "earthquake" appears in the ...
12
votes
4answers
794 views

About Cryptography in a Character Language

Suppose I had a message in Chinese (or another non-phonetic language) and I wanted to encipher it. Some of the simplest encryptions in English are substitution ciphers, but such ciphers don't seem ...