crypto-keygen-suite/keyGen/encryptandecrypt/ciphers/railFenceCipherGenerator.js

Key generation utilities for cryptographic operations. YES I RENAMED IT OMG BASES AND PROTOCOLS!!! See its folder for all <3

import yargs from 'yargs/yargs';
import { hideBin } from 'yargs/helpers';

function railFenceEncrypt(message, rails) {
  const fence = Array.from({ length: rails }, () => []);
  let directionDown = false; // Direction flag for zigzag
  let row = 0;

  for (const char of message) {
      fence[row].push(char);
      if (row === 0 || row === rails - 1) {
          directionDown = !directionDown;
      }
      row += directionDown ? 1 : -1; // Move up or down
  }

  return fence.flat().join('');
}

function railFenceDecrypt(message, rails) {
  const fence = Array.from({ length: rails }, () => []);
  let directionDown = false; // Direction flag for zigzag
  let row = 0;

  for (let i = 0; i < message.length; i++) {
      fence[row].push('*'); // Placeholder for characters
      if (row === 0 || row === rails - 1) {
          directionDown = !directionDown;
      }
      row += directionDown ? 1 : -1; // Move up or down
  }

  let index = 0;
  for (let r = 0; r < rails; r++) {
      for (let c = 0; c < fence[r].length; c++) {
          if (fence[r][c] === '*') {
              fence[r][c] = message[index++];
          }
      }
  }

  let result = '';
  row = 0;
  for (let i = 0; i < message.length; i++) {
      result += fence[row].shift(); // Get the next character
      if (row === 0 || row === rails - 1) {
          directionDown = !directionDown;
      }
      row += directionDown ? 1 : -1; // Move up or down
  }

  return result;
}

const argv = yargs(hideBin(process.argv))
  .option('message', {
      alias: 'm',
      description: 'The message to encrypt or decrypt',
      type: 'string',
      demandOption: true
  })
  .option('rails', {
      alias: 'r',
      description: 'The number of rails to use for encryption or decryption',
      type: 'number',
      demandOption: true
  })
  .option('encrypt', {
      alias: 'e',
      description: 'Set to true to encrypt, false to decrypt',
      type: 'boolean',
      default: true
  })
  .help()
  .argv;

const result = argv.encrypt
  ? railFenceEncrypt(argv.message, argv.rails)
  : railFenceDecrypt(argv.message, argv.rails);

console.log('Result:', result);