🔐 Ceasar

A simple JavaScript library for Caesar cipher encryption and decryption.

Easily shift letters of your message with a Caesar cipher — useful for simple encoding, fun puzzles, or learning about classical encryption techniques.

📦 Installation

Install via npm:

npm install ceasar

🚀 Quick Usage

Node.js (CommonJS)

const { cypher, decypher } = require('ceasar');

const original = "Hello, World!";
const shift = 3;

const encrypted = cypher(original, shift);     // "Khoor, Zruog!"
const decrypted = decypher(encrypted, shift);  // "Hello, World!"

console.log("Encrypted:", encrypted);
console.log("Decrypted:", decrypted);

ES Modules (ESM)

import { cypher, decypher } from 'ceasar';

console.log(cypher("abc", 1));    // bcd
console.log(decypher("bcd", 1));  // abc

🧠 API

cypher(text: string, shift: number): string

Encodes a string using Caesar cipher logic by shifting characters forward.

• text: The input string
• shift: The number of characters to shift by (positive integer)

decypher(text: string, shift: number): string

Decodes a Caesar cipher encoded string by shifting characters backward.

• text: The encrypted string
• shift: The original shift value used during encryption

✨ Examples

cypher("xyz", 3);      // "abc"
decypher("abc", 3);    // "xyz"

cypher("Secret!", 4);  // "Wigvix!"
decypher("Wigvix!", 4) // "Secret!"

🔧 CLI (Coming Soon)

Want to encrypt from the terminal? Stay tuned for CLI support!

📄 License

MIT License © 2025 Mickyas Tesfaye

🙌 Contribute

Feel free to open issues or PRs to improve or extend the library.