```open class SimpleJWT(val secret: String) { private val algorithm = Algorithm.HMAC256(secret) ...

# ktor

[Avadhut]

open class SimpleJWT(val secret: String) {
    private val algorithm = Algorithm.HMAC256(secret)
    val verifier = JWT.require(algorithm).build()
    fun sign(name: String): String = JWT.create().withClaim("name", name).sign(algorithm)
}
fun Application.module() {
    val simpleJwt = SimpleJWT("my-super-secret-for-jwt")
    install(Authentication) {
        jwt {
            verifier(simpleJwt.verifier)
            validate {
                UserIdPrincipal(it.payload.getClaim("name").asString())
            }
        }
    }
    // ...
}

[Pedro Flores]

The withClaim method allows you to add additional information to your JWT Token (see https://jwt.io/ for more info).

The UserIdPrincipal will be a provided Principal to your ApplicationCalls if you're properly authenticated.

[Avadhut]

Can you please elaborate UserIdPrincipal?

[Pedro Flores]

See for example on https://ktor.io/samples/feature/auth.html, you can get info about the current logged user. For example there you can access the claims you’ve setted in the JWT token to identify your user/ do some operations based on role values for example

[Avadhut]

I'll take look at samples. Thanks alot!