com.wa9nnn.PasswordEncrypter.scala Maven / Gradle / Ivy

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Utils for scala3 and playframework 3.x.
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/*
 * Copyright (C) 2022 Dick Lieber, WA9NNN
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see .
 */
package com.wa9nnn

import com.typesafe.scalalogging.LazyLogging
import com.wa9nnn.PasswordEncrypter.keySpec

import java.nio.charset.Charset
import java.util.Base64
import javax.crypto.Cipher
import javax.crypto.spec.SecretKeySpec

/**
 * This is useful for passwords at rest, where hashes are not appropriate.
 * Not very secure, but avoids stooring plain-text when an app needs to use a password.
 *
 * @param secretKey usually something for a given application.
 */
class PasswordEncrypter(secretKey: String)  {
  keySpec = Option(new SecretKeySpec(secretKey.getBytes(), "Blowfish"))
}

object PasswordEncrypter extends LazyLogging {
  var keySpec: Option[SecretKeySpec] = None
  val prefix: String = "{b}:"
  val prefixLength: Int = prefix.length
  val charset: Charset = Charset.forName("UTF-8")


  def isEncrypged(candidate: String): Boolean = candidate.startsWith(prefix)

  def encrypt(plainText: String): String = {
    import java.util.Base64
    import javax.crypto.Cipher
    keySpec
      .map {ks =>

        val cipher = Cipher.getInstance("Blowfish")
        cipher.init(Cipher.ENCRYPT_MODE, ks)
        val bytes = cipher.doFinal(plainText.getBytes(charset))
        logger.trace("encrpt: encrypted bytes: {}", bytes)
        val encryptedtext = Base64.getEncoder.encodeToString(bytes)
        s"$prefix$encryptedtext"
      }.getOrElse(throw new IllegalStateException("PasswordEncrypter was not loaded"))

  }

  def decrypt(maybeEncrypted: String): String = {
    keySpec
      .map { ks =>
      def doDecrypt(reallyEncrypted: String): String = {

          val bytes = Base64.getDecoder.decode(reallyEncrypted)

          logger.trace("decrypt: encrypted bytes: {}", bytes)
          val cipher = Cipher.getInstance("Blowfish")
          cipher.init(Cipher.DECRYPT_MODE, ks)
          val decrypted = cipher.doFinal(bytes)

          val str = new String(decrypted, charset)
          logger.trace("decrypt: decrypted: {}", str)
          str
        }

      if (maybeEncrypted startsWith prefix)
        doDecrypt(maybeEncrypted.drop(prefixLength))
      else
        maybeEncrypted
    }.getOrElse(throw new IllegalStateException("PasswordEncrypter was not loaded"))
  }
}