gistfile1.scala

package hexapoda.core.interaction
import hexapoda.core.entity.User
import hexapoda.core.gateway.UserFetcher
import javax.crypto.SecretKeyFactory
import javax.crypto.spec.PBEKeySpec

class UserAuthenticator(userFetcher: UserFetcher) {
  def apply(emailAddress: String, password: String) =
    userFetcher.findUserByEmailAddress(emailAddress)
               .filter(UserAuthenticator.checkPassword(password, _))
               .map(_.id.value)
}

object UserAuthenticator {
  val secretKeyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1")

  private def checkPassword(password: String, user: User) =
    checkPassword(password,
                  user.passwordHash,
                  user.passwordSalt,
                  user.passwordIterationCount)

  private def checkPassword(password: String,
                            passwordHash: Array[Byte],
                            passwordSalt: Array[Byte],
                            passwordIterationCount: Int) = {
      val keySpec = new PBEKeySpec(password.toCharArray,
                                   passwordSalt,
                                   passwordIterationCount,
                                   passwordHash.length * 8)
      val hash = secretKeyFactory.generateSecret(keySpec).getEncoded
      hash.toSeq == passwordHash.toSeq
  }
}