cryptia/core/engine.js

Cryptia is a simple JavaScript library for encrypting and decrypting text using a basic substitution cipher. It provides an easy-to-use interface for securing text data in client-side applications..

import {
  $primarySymbols,
  $revPrimarySymbols,
  $generalPunctuation,
  $revGeneralPunctuation,
  $currencySymbols,
  $revCurrencySymbols,
  $latinSymbols,
  $revLatinSymbols
} from '../cipher/characters.js'

function generateKey (key, obfuscationLevel) {
  const baseKey = `abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890 ${$primarySymbols}${$generalPunctuation}${$currencySymbols}${$latinSymbols}`

  const baseKeyWithSpace = baseKey
  const keySum = [...key].reduce((sum, char) => sum + char.charCodeAt(0), 0)

  const obfuscate = chars =>
    chars
      .split('')
      .sort(
        (a, b) =>
          (((a.charCodeAt(0) + keySum) * obfuscationLevel) % chars.length) -
          (((b.charCodeAt(0) + keySum) * obfuscationLevel) % chars.length)
      )
      .join('')

  const shuffled = obfuscate(baseKeyWithSpace)

  return { encryptionKey: baseKey, decryptionKey: shuffled }
}
export function encryptionAlgorithm (
  text,
  key,
  obfuscationLevel,
  preserveWhitespace
) {
  const { encryptionKey, decryptionKey } = generateKey(key, obfuscationLevel)
  let encryptedText = ''

  for (const char of text) {
    const index = encryptionKey.indexOf(char)
    if (index === -1) {
      encryptedText += char
    } else {
      encryptedText += decryptionKey[index]
    }
  }

  if (preserveWhitespace) {
    encryptedText = encryptedText
      .replace(/ /g, '_SPACE_')
      .replace(/\n/g, '_NEWLINE_')
  }

  return encryptedText
}

export function decryptionAlgorithm (
  encryptedText,
  key,
  obfuscationLevel,
  preserveWhitespace
) {
  if (preserveWhitespace) {
    encryptedText = encryptedText
      .replace(/_SPACE_/g, ' ')
      .replace(/_NEWLINE_/g, '\n')
  }

  const { encryptionKey, decryptionKey } = generateKey(key, obfuscationLevel)

  let decryptedText = ''

  for (const char of encryptedText) {
    const index = decryptionKey.indexOf(char)
    if (index === -1) {
      decryptedText += char
    } else {
      decryptedText += encryptionKey[index]
    }
  }

  return decryptedText
}