DES and AES encryption in Scala

build.sbt

name := "DES and AES encryption in Scala"

version := "1.0"

scalaVersion := "2.9.1"

libraryDependencies += "commons-codec" % "commons-codec" % "1.6"

main.scala

package protocol {

  import annotation.implicitNotFound

  import java.io.{DataOutputStream, ByteArrayOutputStream}

  @implicitNotFound(msg = "Could not find a Writes for ${T}")
  trait Writes[T] {

    def writes(value: T): Array[Byte]
  }

  class DataOutputStreamWrites[T](writeValue: (DataOutputStream, T) => Unit) extends Writes[T] {

    def writes(value: T): Array[Byte] = {
      val bos = new ByteArrayOutputStream
      val dos = new DataOutputStream(bos)
      writeValue(dos, value)
      dos.flush()
      val byteArray = bos.toByteArray
      bos.close()
      byteArray
    }
  }

  object defaults {
    implicit object WritesString extends Writes[String] {
      def writes(value: String) = value.getBytes("UTF-8")
    }
    implicit object WritesLong extends DataOutputStreamWrites[Long](_.writeLong(_))
    implicit object WritesInt extends DataOutputStreamWrites[Int](_.writeInt(_))
    implicit object WritesShort extends DataOutputStreamWrites[Short](_.writeShort(_))
  }
}

package crypto {

  import protocol.Writes

  import javax.crypto.spec.SecretKeySpec
  import javax.crypto.Cipher

  trait Encryption {
    def encrypt(dataBytes: Array[Byte], secret: String): Array[Byte]
    def decrypt(codeBytes: Array[Byte], secret: String): Array[Byte]

    def encrypt[T:Writes](data: T, secret: String): Array[Byte] = encrypt(implicitly[Writes[T]].writes(data), secret)
  }

  class JavaCryptoEncryption(algorithmName: String) extends Encryption {

    def encrypt(bytes: Array[Byte], secret: String): Array[Byte] = {
      val secretKey = new SecretKeySpec(secret.getBytes("UTF-8"), algorithmName)
      val encipher = Cipher.getInstance(algorithmName + "/ECB/PKCS5Padding")
      encipher.init(Cipher.ENCRYPT_MODE, secretKey)
      encipher.doFinal(bytes)
    }

    def decrypt(bytes: Array[Byte], secret: String): Array[Byte] = {
      val secretKey = new SecretKeySpec(secret.getBytes("UTF-8"), algorithmName)
      val encipher = Cipher.getInstance(algorithmName + "/ECB/PKCS5Padding")
      encipher.init(Cipher.DECRYPT_MODE, secretKey)
      encipher.doFinal(bytes)
    }
  }

  object DES extends JavaCryptoEncryption("DES")
  object AES extends JavaCryptoEncryption("AES")
}

object Main extends App {

  import org.apache.commons.codec.binary.Base64

  import crypto._
  import protocol.defaults._

  def encodeBase64(bytes: Array[Byte]) = Base64.encodeBase64String(bytes)

  println(encodeBase64(DES.encrypt("hoge", "01234567")))
  //=> vyudTtnBJfs=

  println(encodeBase64(AES.encrypt("hoge", "0123456789012345")))
  //=> QWSouZUMVYMfS86xFyBgtQ==

  println(encodeBase64(DES.encrypt(123L, "01234567")))
  //=> Cqw2ipxTtvIIu122s3wG1w==

  println(encodeBase64(DES.encrypt(123, "01234567")))
  //=> BV+LSCSYmUU=
}