tsec-hmac-example.scala

package io.github.jmcardon.tseclogin

import tsec.common._
import tsec.mac.core.MAC
import tsec.mac.imports._
import java.util.UUID
import java.time._
import cats.effect.IO

//Using cats-effect 0.5.0 and tsec 0.0.1-M6

object HmacExample {

  case class Order(
      orderNumber: UUID,
      email: String,
      timestamp: Instant,
      nonce: SecureRandomId,
      hash: MAC[HMACSHA256]
  )

  def authenticateOrderParams(
      ord: UUID,
      email: String,
      time: Instant,
      nonce: SecureRandomId,
      key: MacSigningKey[HMACSHA256]
  ): IO[MAC[HMACSHA256]] =
    for {
      concat <- IO.pure((ord.toString + email + time.toString + nonce).utf8Bytes)
      hashed <- JCAMac.sign[IO, HMACSHA256](concat, key)
    } yield hashed

  def generateOrder(key: MacSigningKey[HMACSHA256]): IO[Order] =
    for {
      ord   <- IO(UUID.randomUUID())
      email <- IO.pure("hi@hi")
      time  <- IO(Instant.now())
      id    <- IO(SecureRandomId.generate)
      mac   <- authenticateOrderParams(ord, email, time, id, key)
    } yield Order(ord, email, time, id, mac)

  def checkOrder(
      order: Order,
      ord: UUID,
      email: String,
      time: Instant,
      nonce: SecureRandomId,
      key: MacSigningKey[HMACSHA256]
  ): IO[Boolean] =
    for {
      concat   <- IO.pure((ord.toString + email + time.toString + nonce).utf8Bytes)
      verified <- JCAMac.verify[IO, HMACSHA256](concat, order.hash, key)
    } yield verified

  def main(args: Array[String]): Unit = {
    val sillyProgram: IO[Unit] = for {
      key      <- HMACSHA256.generateLift[IO] //get a key
      order    <- generateOrder(key)
      verified <- checkOrder(order, order.orderNumber, order.email, order.timestamp, order.nonce, key)
    } yield println(s"Order number ${order.orderNumber} has been verified as $verified!!")
    
    sillyProgram.unsafeRunSync()
  }

}