Code for doing crypto-stuff in Java.

Charles Reid 4579b198b0 Adding FULL Combos, new Plugboard, and need-to-revisit Rotors.		8 years ago
affine	Adding several affine programs	8 years ago
caesar	updating puzzle levels	8 years ago
enigma	Adding FULL Combos, new Plugboard, and need-to-revisit Rotors.	8 years ago
mod	dividing up scripts into relevant categories.	8 years ago
moscow	dividing up scripts into relevant categories.	8 years ago
primes	adding print primes	8 years ago
puzzles	updating puzzles	8 years ago
.gitignore	Initial commit	8 years ago
LICENSE	Initial commit	8 years ago
README.md	initial commit of files	8 years ago

README.md

java-crypto

Code for doing cryptography in Java.

Crypto Math Classes

Crypto Math: Modular Arithmetic

The Modular Arithmetic class is a static class with methods useful in doing modular arithmetic. These include finding gcds, factoring modulo a number, computing exponents, finding inverses, etc.

gcd(a,b)
extendedEuclidian(xy[], a, b)
solve(a,c,n)
inverseMod(a,n)

Cipher Implementations:

Cipher Implementation: Caesar Cipher

The Caesar class implements the Caesar cipher, which is a simple rotation (ROT) cipher with a key between 0 and 25.

Cipher Implementation: Affine Cipher

The Affine class implements the Affine cipher, which implements both a multiplicative and an additive shift. The key has two parts.

If the letters are indexed from 0 to 25, they are shifted according to the formula: formula:

a x + b (mod 26)

where a is the first part of the key and b is the second part of the key. This requires that gcd(a,26) = 1.