Caesar Cipher (Keyed Caesar) java library

Java library for Ceasar Cipher (Keyed Caesar) that can:

1. Encrypt & decrypt english text using keyword and keyword offset (shift)
2. Hack encrypted english text using frequency of letters and dictionary of words

Requirements

• Java JDK 1.8 or later

Installation

Maven users

<dependency>
  <groupId>com.github.maximan3000</groupId>
  <artifactId>caesar-cipher</artifactId>
  <version>1.0.0</version>
</dependency>

Gradle Groovy DSL

implementation 'com.github.maximan3000:caesar-cipher:1.0.0'

Algorithm

• Read it on wikipedia.org

Usage

Encrypt/Decrypt text

Create an encryption system instance

import com.grayen.encryption.caesar.algorithm.Caesar;
import com.grayen.encryption.caesar.algorithm.implementation.CaesarFabric;

Caesar encryption = CaesarFabric.getEncryptionSystem();

Encrypt text using your keywords and offset or it's default values

String textToEncrypt = "Text need to encrypt";

String encryptedText = encryption.encrypt(textToEncrypt, "keyword", 5);

Decrypt with the same way

String textToDecrypt = "Xcyx pccb xq cpauwsx";

String decryptedText = encryption.decrypt(textToDecrypt, "keyword", 5);

Hack text

Hack system uses dictioanry with english words to improve hacking quality. So you need to create string array with many words. To do that, download large book with .txt extention and parse it to string[].

import java.nio.file.FileSystems;
import java.nio.charset.StandardCharsets;
import java.nio.file.Path;
import java.nio.file.Files;

Path sourceFile = FileSystems.getDefault().getPath("BigBook.txt");
List<String> fileLines = Files.readAllLines(sourceFile, StandardCharsets.UTF_8);
String[] dictionary = fileLines.toArray(new String[0]);

Create hack system instance.

• Note 1: successful hack depends on encrypted text size
• Note 2: text for dictionary should be large

import com.grayen.encryption.caesar.hack.Hack;
import com.grayen.encryption.caesar.hack.implementation.HackFactory;

Hack hack = HackFactory.getCaesarEncryptionHack(encryptedText, dictionary);

Hack encrypted text

String hackedText = hack.hack();

If it's need, correct hacked text with hands and hack the text again

hack.correctEncryptionTableWithHand("a", "x");
String hackedText = hack.hack();