Handling JWT Validation with only RSA X.509 Public Key

JwtSecurityConfig.kt

package mn.max

import io.micronaut.context.annotation.Value
import io.micronaut.security.token.jwt.signature.rsa.RSASignatureConfiguration
import java.security.KeyFactory
import java.security.interfaces.RSAPublicKey
import java.security.spec.X509EncodedKeySpec
import java.util.*
import javax.inject.Named
import javax.inject.Singleton

@Singleton
@Named("validation")
class JwtSecurityConfig : RSASignatureConfiguration {

    @Value("\${jwt-config.key:MISSING_KEY}")
    var key = "TODO"

    override fun getPublicKey(): RSAPublicKey {
        val publicKey = KeyFactory.getInstance("RSA")
                .generatePublic(X509EncodedKeySpec(Base64.getDecoder().decode(key)))
        return publicKey as RSAPublicKey
    }
}