1VQFjaiR

1import cats.data.Kleisli
2import cats.effect.Sync
3import com.google.common.io.BaseEncoding
4import javax.crypto.spec.{IvParameterSpec, PBEKeySpec, SecretKeySpec}
5import javax.crypto.{Cipher, SecretKeyFactory}
6
7object Hasher {
8  type Key = (String, String)
9
10  final case class InvalidInputException(hash: String, ex: Throwable) extends IllegalArgumentException(s"Could not decrypt [$hash]", ex)
11
12  private val iv: Array[Byte] = Array.fill(16)(0)
13  private val serde = BaseEncoding.base64Url().omitPadding()
14
15  private def secretKey[F[_]](implicit F: Sync[F]): Kleisli[F, Key, SecretKeySpec] = Kleisli(config => F.delay {
16    val factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256")
17    val spec = new PBEKeySpec(config._1.toCharArray, config._2.getBytes(), 65536, 256)
18    val tmp = factory.generateSecret(spec)
19    new SecretKeySpec(tmp.getEncoded, "AES")
20  })
21
22  def encrypt[F[_]](input: String)(implicit F: Sync[F]): Kleisli[F, Key, String] = for {
23    secret <- secretKey
24    iparam <- Kleisli.liftF(F.pure(new IvParameterSpec(iv)))
25    cipher <- Kleisli.liftF(F.delay {
26      val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding")
27      cipher.init(Cipher.ENCRYPT_MODE, secret, iparam)
28      cipher.doFinal(input.getBytes)
29    })
30    hash   <- Kleisli.liftF(F.delay(serde.encode(cipher)))
31  } yield hash
32
33  def decrypt[F[_]](input: String)(implicit F: Sync[F]): Kleisli[F, Key, String] = for {
34    secret <- secretKey
35    hash   <- Kleisli.liftF(F.delay(serde.decode(input)))
36    iparam <- Kleisli.liftF(F.pure(new IvParameterSpec(iv)))
37    cipher <- Kleisli.liftF(F.delay {
38      val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding")
39      cipher.init(Cipher.DECRYPT_MODE, secret, iparam)
40      cipher.doFinal(hash)
41    })
42    value <- Kleisli.liftF(F.delay {
43      new String(cipher)
44    })
45  } yield value
46}