HmacSHA256.scala

import org.bouncycastle.jce.provider.BouncyCastleProvider
import org.bouncycastle.util.Strings

import java.security.Security
import java.util.Base64
import javax.crypto.Mac
import javax.crypto.spec.SecretKeySpec

Security.addProvider(new BouncyCastleProvider())

val macKey = new SecretKeySpec(
  Base64.getDecoder.decode("QwKFZpTiEcXnLdbbGEdzcO57/yoIVGOpixXfeKGLDdg="), // Secret
  "HmacSHA256"
)

val data = Strings.toByteArray("Hello World")

val mac = Mac.getInstance("HmacSHA256", "BC")
mac.init(macKey)
mac.update(data)

Base64.getEncoder.encodeToString(mac.doFinal())
//IFVv0O2lWoHNjEEsGcL9YOiaPNWkHIVkpCiiTKsp1ac=