These tutorials target Micronaut Framework 3. Read, Guides for Micronaut Framework 4.

Table of Contents

JWK Keys endpoint

Learn how to expose a keys endpoint with primary and secondary JSON Web Key (JWK)

Authors: Sergio del Amo

Micronaut Version: 3.9.2

1. Getting Started

In this guide, we will create a Micronaut application written in Kotlin.

In this guide, you load a primary and secondary JWK from their JSON representation. Both keys participate as token validators. Moreover, the primary participates in token generation. Also, you expose their public keys as JWKS in a /keys endpoint.

A JSON Web Key (JWK) is a JSON object that represents a cryptographic key. You can use a remote JWK Set, a JSON object that represents a set of JWKs, to validate JWT signatures.

Meanwhile, a JWK Set is a JSON object that represents a set of JWKs. The JSON object must have a "keys" member, which is an array of JWKs.

2. What you will need

To complete this guide, you will need the following:

  • Some time on your hands

  • A decent text editor or IDE

  • JDK 1.8 or greater installed with JAVA_HOME configured appropriately

3. Solution

We recommend that you follow the instructions in the next sections and create the application step by step. However, you can go right to the completed example.

4. Writing the Application

Create an application using the Micronaut Command Line Interface or with Micronaut Launch.

mn create-app example.micronaut.micronautguide --build=maven --lang=kotlin
If you don’t specify the --build argument, Gradle is used as the build tool.
If you don’t specify the --lang argument, Java is used as the language.

The previous command creates a Micronaut application with the default package example.micronaut in a directory named micronautguide.

Setup IntelliJ IDEA to develop Micronaut Applications.

4.1. Configuration

Write an interface to encapsulate the configuration of the JSON Web Keys:

src/main/kotlin/example/micronaut/JwkConfiguration.kt
package example.micronaut

interface JwkConfiguration {

    val primary: String

    val secondary: String
}

The application signs JSON Web tokens with the primary key.

The application uses both primary and secondary keys to validate JSON Web Tokens.

A rotation policy could be:

  • Set the secondary key with the primary key value.

  • Set the primary key with a new value.

Please note that the JSON Web Token expiration date should be shorter than the key rotation window.

Create a @ConfigurationProperties implementation of the interface

src/main/kotlin/example/micronaut/JwkConfigurationProperties.kt
package example.micronaut

import io.micronaut.context.annotation.ConfigurationProperties
import javax.validation.constraints.NotBlank

@ConfigurationProperties("jwk") (1)
class JwkConfigurationProperties : JwkConfiguration {

    @NotBlank (2)
    override lateinit var primary: String

    @NotBlank (2)
    override lateinit var secondary: String
}
1 The @ConfigurationProperties annotation takes the configuration prefix.
2 You can use validation constraints in the @ConfigurationProperties objects.

4.2. Secondary Key

Create an abstract class which parses RSA Keys from JWK JSON Strings.

src/main/kotlin/example/micronaut/AbstractRSASignatureConfiguration.kt
package example.micronaut

import com.nimbusds.jose.JOSEException
import com.nimbusds.jose.JWSAlgorithm
import com.nimbusds.jose.jwk.JWK
import com.nimbusds.jose.jwk.RSAKey
import io.micronaut.context.exceptions.ConfigurationException
import io.micronaut.security.token.jwt.signature.rsa.RSASignatureConfiguration
import org.slf4j.LoggerFactory
import java.security.interfaces.RSAPrivateKey
import java.security.interfaces.RSAPublicKey
import java.text.ParseException
import java.util.Optional

abstract class AbstractRSASignatureConfiguration(jsonJwk: String) : RSASignatureConfiguration { (1)

    val publicJWK: JWK
    val pubKey: RSAPublicKey
    val privKey: RSAPrivateKey
    val algorithm: JWSAlgorithm

    init {
        val primaryRSAKey = parseRSAKey(jsonJwk)
                .orElseThrow { ConfigurationException("could not parse primary JWK to RSA Key") }

        publicJWK = primaryRSAKey.toPublicJWK()

        privKey = try {
            primaryRSAKey.toRSAPrivateKey()
        } catch (e: JOSEException) {
            throw ConfigurationException("could not primary RSA private key")
        }

        pubKey = try {
            primaryRSAKey.toRSAPublicKey()
        } catch (e: JOSEException) {
            throw ConfigurationException("could not primary RSA public key")
        }

        algorithm = parseJWSAlgorithm(primaryRSAKey)
                .orElseThrow { ConfigurationException("could not parse JWS Algorithm from RSA Key") }
    }

    override fun getPublicKey(): RSAPublicKey? = pubKey

    fun getJwsAlgorithm(): JWSAlgorithm = algorithm

    fun getPrivateKey(): RSAPrivateKey = privKey

    private fun parseJWSAlgorithm(rsaKey: RSAKey): Optional<JWSAlgorithm> {
        val algorithm = rsaKey.algorithm ?: return Optional.empty()
        return if (algorithm is JWSAlgorithm) {
            Optional.of(algorithm)
        } else Optional.of(JWSAlgorithm.parse(algorithm.name))
    }

    private fun parseRSAKey(jsonJwk: String): Optional<RSAKey> {
        return try {
            val jwk = JWK.parse(jsonJwk)
            if (jwk !is RSAKey) {
                LOG.warn("JWK is not an RSAKey")
                return Optional.empty()
            }
            Optional.of(jwk)
        } catch (e: ParseException) {
            LOG.warn("Could not parse JWK JSON string {}", jsonJwk)
            Optional.empty()
        }
    }

    companion object {
        private val LOG = LoggerFactory.getLogger(AbstractRSASignatureConfiguration::class.java)
    }
}
1 beans of type RSASignatureConfiguration participate as token validators.

Throwing a io.micronaut.context.exceptions.ConfigurationException in a constructor when some configuration parsing fails is a common idiom in Micronaut applications.

Secondary Configuration

Create a refreshable bean to load the secondary key:

src/main/kotlin/example/micronaut/SecondarySignatureConfiguration.kt
package example.micronaut

import io.micronaut.runtime.context.scope.Refreshable

@Refreshable (1)
class SecondarySignatureConfiguration(jwkConfiguration: JwkConfiguration) :
        AbstractRSASignatureConfiguration(jwkConfiguration.secondary)
1 @Refreshable scope is a custom scope that allows a bean’s state to be refreshed via the /refresh endpoint.

4.3. Primary Key

Create an abstract class which extends from AbstractRSASignatureConfiguration and implements RSASignatureGeneratorConfiguration.

src/main/kotlin/example/micronaut/AbstractRSAGeneratorSignatureConfiguration.kt
package example.micronaut

import io.micronaut.security.token.jwt.signature.rsa.RSASignatureGeneratorConfiguration

abstract class AbstractRSAGeneratorSignatureConfiguration(jsonJwk: String) :
        AbstractRSASignatureConfiguration(jsonJwk), RSASignatureGeneratorConfiguration (1)
1 beans of type RSAGeneratorSignatureConfiguration can be used as token generators.

Primary Configuration

Create a refreshable bean to load the primary key:

src/main/kotlin/example/micronaut/PrimarySignatureConfiguration.kt
package example.micronaut

import io.micronaut.runtime.context.scope.Refreshable
import jakarta.inject.Named

@Refreshable (1)
@Named("generator") (2)
class PrimarySignatureConfiguration(jwkConfiguration: JwkConfiguration) :
        AbstractRSAGeneratorSignatureConfiguration(jwkConfiguration.primary)
1 @Refreshable scope is a custom scope that allows a bean’s state to be refreshed via the /refresh endpoint.
2 You need to qualify with @Named generator the signature configuration bean which you wish to use to sign your JSON web tokens.

4.4. JWKProvider

To enable the Keys Controller you have to provide at least a bean of type: JwkProvider.

src/main/kotlin/example/micronaut/JsonWebKeysProvider.kt
package example.micronaut

import com.nimbusds.jose.jwk.JWK
import io.micronaut.runtime.context.scope.Refreshable
import io.micronaut.security.token.jwt.endpoints.JwkProvider

@Refreshable (1)
class JsonWebKeysProvider(primaryRsaPrivateKey: PrimarySignatureConfiguration,
                          secondarySignatureConfiguration: SecondarySignatureConfiguration) : JwkProvider { (2)

    private val jwks: List<JWK>

    init {
        jwks = listOf(primaryRsaPrivateKey.publicJWK, secondarySignatureConfiguration.publicJWK)
    }

    override fun retrieveJsonWebKeys(): List<JWK> = jwks
}
1 @Refreshable scope is a custom scope that allows a bean’s state to be refreshed via the /refresh endpoint.
2 Create a bean of type JwkProvider

5. Writing Tests

5.1. Token Generation Test

Create a test to verify that the application can generate a signed JSON Web Token.

src/test/kotlin/example/micronaut/TokenGeneratorTest.kt
package example.micronaut

import com.nimbusds.jwt.JWT
import com.nimbusds.jwt.JWTParser
import com.nimbusds.jwt.SignedJWT
import io.micronaut.context.annotation.Property
import io.micronaut.security.token.generator.TokenGenerator
import io.micronaut.security.token.validator.TokenValidator
import io.micronaut.test.extensions.junit5.annotation.MicronautTest
import jakarta.inject.Inject
import org.junit.jupiter.api.Assertions.assertDoesNotThrow
import org.junit.jupiter.api.Assertions.assertEquals
import org.junit.jupiter.api.Assertions.assertTrue
import org.junit.jupiter.api.Test

(1)
@Property(name = "jwk.primary", value = "{\"p\":\"_OZyH1Mk3wR0oXw1C31t4kWOcaHFB6Njro1cYx52REnPiznn_JTtwvlAMpvV6LVCIZPgKMzdIEMY1gYs1LsO-5IFqWwegXmYJ0iKXbRrZshfWBCzRLK3QK5fER1le1XUBDhtDk7KIW_Xg-SZF4pf_LUEVKMnyUpspGI5F77jlJ8\",\"kty\":\"RSA\",\"q\":\"s9wvl7z8vkHQvo9xOUp-z0a2Z7LFBDil2uIjPh1FQzs34gFXH8dQPRox83TuN5d4KzdLPqQNQAfMXU9_KmxihNb_qDQahYugeELmcem04munxXqBdyZqWhWCy5YmujYqn44irwvoTbw6_RkMqjCmINPTPadptlPivsZ6RhKn8zk\",\"d\":\"ok3wmhOy8NZEHAotnFiH6ecFD6xf_9x33_fMRkqa3_KE8NZM7vmvNgElox2UvcP_2K5E7jOdL2XQdJCTIW3Qlj66yE2a84SYlbvxIc4hDrIog0XNt4FhavvshxxUIfDQo6Q8qXDR5v7nwt6SCopYC3t3KVRdJh08GzKoVxysd7afJjxXxx178gY29uMRqnwxFN1OGnWaiBr-xGKb1frJ6jOI1zvuuCaljZ4aZjc9vOR4y9ZmobgrzkMFnpDAmQZ7MWcVMyodRMOA2dEOckywPhg-dIVNiVIqzJqe5Yg1ilNookjwtqj2TpNU7Z9gPqzYB73PmQ2p5LMDheAPxcOmEQ\",\"e\":\"AQAB\",\"use\":\"sig\",\"kid\":\"e3be37177a7c42bcbadd7cc63715f216\",\"qi\":\"r--nAtaYPAgJq_8R1-kynpd53E17n-loDUgtVWBCx_RmdORX4Auilv1S83dD1mbcnYCbV_LmxiEjOiz-4gS_E0qVGqakAqQrO1hVUvJa_Y2uftDgwFmuJNGbpRU-K4Td_uUzdm48za8yJCgOdYsWp6PNMCcmQgiInzkR3XYV83I\",\"dp\":\"oQUcvmMSw8gzdin-IB2xW_MLecAVEgLu0dGBdD6N8HbKZQvub_xm0dAfFtnvvWXDAFwFyhR96i-uXX67Bos_Q9-6KSAE4E0KGmDucDESfPOw-QJREbl0QgOD1gLQfVGtVy6SCR0TR2zNXFWtP7bD3MNoSXdEOr5fI97CGSNaBWM\",\"alg\":\"RS256\",\"dq\":\"DM-WJDy10-dkMu6MpgQEXEcxHtnA5rgSODD7SaVUFaHWLSbjScQslu2SuUCO5y7GxG0_0spklzb2-356FE98BPI7a4Oqj_COEYLSXzLCS45XeN1s80utL5Vwp4eeYo0RJCQ_nDBA76iEmxp5qHWmn5f25-FQykfXUrdYZj1V8SE\",\"n\":\"sa6m2i-iNvj6ZSTdSHZaBrnv6DId4AqAXhOyl0yA5fNWYe6r51h24SXqk7DsGYHHh74ii74tP1lTpmy6RD67tCK-tbN-d6yc4Z6FfM8R83v2QZUfaAixgHGtw0n2toqsiHf6EloDV-B8q4GYyKDD6cLecoaIuTmMBTY3kts59U2t9W10YoLGsmFqLSz8qNF5HkahzB6_--2DiBfVGUKAXHC-SICGZCi-8efOetv6pt9vFiWEgwU_DgjRNYzLFt1SEmbGFUU4kbjQ7tNTMkHfzfwcT6qLt4kVKy2FNYsEMk24keWtCvW_RyO_fisZc0W9smX7WtYjEXhcAjDeqHgEZw\"}")
@Property(name = "jwk.secondary", value = "{\"p\":\"4qJ9RNlu6SuDT_MLArfzimvKEwmet_j12Z9EQeb5nMjZIOHTcWw__duebUytfWwxsRHhtSVXeMt-EryQAOulm2p1bfiVuparq93z9P5cPnb0oArFaw3eFNFEmX5U-lY8PzUTTsFxO4aVQYAKXD6DP7p5uPzuwpHFuNc71nNIXZE\",\"kty\":\"RSA\",\"q\":\"v4OhkWMbS_nq77HFanwZAT_obfJuQfOFOQBORL4ATAHGUXm2y4YqLNExZs7Wj1MA_6ya6Y00s2JBM7fWq_fPe4d9xo5aGrPdcp0G8W21kkfh9vuVPlHVQTgSP7FQ9qahvXxNwK_11yNr3p1HBmScJ5mHlMBpIJsFcvHA-uXe0Ps\",\"d\":\"EunrjnQ1-jJPSCrt2L94PUpDrakup8a4pXys52YSkJY-W6XidM0roOS6kr06P3G6VQgc6AL_BkvTQ_XS0oXHbXVprDQ5Syam5p9oxHBhhW_vSqIMgUOfm28uyB3Mtw9rBxdUxW3yElHioaR8a-exYhhyVXb1QEhxL_rcnthmhAkM2NcHi2UnxGKFTsC0abQ2MuQc1OAuW5veDiIF2hfdC41qE0_d8vB6FDWbblgUpbwB6uSZaViPs15Buq2oX9dCCw54-PgzkfehDt7lyqgupktbV1psnVVhL86shzt4QFnhd3k7VpFbjCNFtiJTrufV-XBWT0pl2w3VR9wrHJ1bYQ\",\"e\":\"AQAB\",\"use\":\"sig\",\"kid\":\"0794e938379540dc8eaa559508524a79\",\"qi\":\"jy-TNyXVy_44_n4KGAwIbZO2C4r6uNWuEdehBfQKkPhiP90myG1KZVfOoKNOK9bCv2mvZJcBz4c1ArElgpuSCV4-KFac1ZzQo_ic5aoIej8Qa80y2ogc-_Yv6_ZLHC1S76M-lm4jayk2-rvuBpy2pUvHbW6Srhs_szwz7ZfSkLg\",\"dp\":\"ApqdV9ortRAj7Ro8ySY17SQ56SgWI8T_hiWXUi6GNa_1FrShik8VGSSZ2GWmJKfGlmM_NaadL60e4LY77VbHy1ZYzQ-rIL60cEAXmnwFsU4Kl4AoLoe1QoX5BM53yXyOKqfAdgow898i_eKru82YEnZhCagWUjP8kpgefuNKNJE\",\"alg\":\"RS256\",\"dq\":\"bFF78WoXh0pMCdQHL2oPDnjh8kWa_OxKHmpA2nqIWnTqgSyRKd2xPvX2tgooqpmsx-8NEymNdCQPcrv4y_z2OgzxI3tiFRZEGs4bnjOJ7bmAYZv71mqcbi3TjHiyrT6j3jNPGrurFUpweVGFWWVQOMmKOKT3ELz9QPzhREb9Vj8\",\"n\":\"qYvDpV8DRU5hx9eXpE4Ms8nUXicEwrxUUz5gb5gkXpIeY82mqfQKKCP6PSFnkKYtRFTOUSm9cgGGfOd7O4NFsIsxLwXCj34X7ORr19eXKBLvG3bZJLxqRlbYuQshDMkQOui1sDBxvYnj5p4iHne6l2btH5grHOCShUWG-bKps5Y8bKNHod1pIOOBabVCmn3sUVUkZw8nyXkQqZbv-c8x6z0TEfhNOPOIt2AmmlNgrE_8g7-dnCvqfJnhv0c7qkOJzsb7OMmvVwsQNiM59D6uaWZr-vdANo6NggiZmCKUS3tpUvdXW7ec9WMPJWhrVEkRcbWXQnZ_C7pXFrz7rLeNKw\"}")
@MicronautTest(startApplication = false)
class TokenGeneratorTest {

    @Inject
    lateinit var tokenGenerator: TokenGenerator

    @Inject
    lateinit var tokenValidator: TokenValidator

    @Test
    fun canGenerateSignedJsonWebTokens() {

        val jwtOptional = tokenGenerator.generateToken(mapOf("sub" to "sergio"))
        assertTrue(jwtOptional.isPresent)

        val jwtString = jwtOptional.get()
        assertDoesNotThrow<JWT> { JWTParser.parse(jwtString) }

        val jwt = JWTParser.parse(jwtString)
        assertTrue(jwt is SignedJWT)

        tokenValidator.validateToken(jwtString, null)

        assertEquals(1, jwt.jwtClaimsSet.claims.keys.size)
        assertEquals("sergio", jwt.jwtClaimsSet.subject)
    }
}
1 See how to generate a JSON Web Key in the guide: JWK generation with a Micronaut command line application

5.2. Secondary signature validation

Create a test to verify that the application can validate a JSON Web Token signed with the secondary key.

src/test/kotlin/example/micronaut/ValidateSecondarySignedJwtTest.kt
package example.micronaut

import com.nimbusds.jwt.JWT
import com.nimbusds.jwt.JWTParser
import com.nimbusds.jwt.SignedJWT
import io.micronaut.context.annotation.Property
import io.micronaut.security.token.generator.TokenGenerator
import io.micronaut.security.token.jwt.generator.JwtTokenGenerator
import io.micronaut.security.token.jwt.generator.claims.ClaimsGenerator
import io.micronaut.security.token.jwt.signature.SignatureGeneratorConfiguration
import io.micronaut.security.token.jwt.signature.rsa.RSASignatureGenerator
import io.micronaut.security.token.validator.TokenValidator
import io.micronaut.test.extensions.junit5.annotation.MicronautTest
import jakarta.inject.Inject
import org.junit.jupiter.api.Assertions.assertDoesNotThrow
import org.junit.jupiter.api.Assertions.assertTrue
import org.junit.jupiter.api.Test

(1)
@Property(name = "jwk.primary", value = "{\"p\":\"_OZyH1Mk3wR0oXw1C31t4kWOcaHFB6Njro1cYx52REnPiznn_JTtwvlAMpvV6LVCIZPgKMzdIEMY1gYs1LsO-5IFqWwegXmYJ0iKXbRrZshfWBCzRLK3QK5fER1le1XUBDhtDk7KIW_Xg-SZF4pf_LUEVKMnyUpspGI5F77jlJ8\",\"kty\":\"RSA\",\"q\":\"s9wvl7z8vkHQvo9xOUp-z0a2Z7LFBDil2uIjPh1FQzs34gFXH8dQPRox83TuN5d4KzdLPqQNQAfMXU9_KmxihNb_qDQahYugeELmcem04munxXqBdyZqWhWCy5YmujYqn44irwvoTbw6_RkMqjCmINPTPadptlPivsZ6RhKn8zk\",\"d\":\"ok3wmhOy8NZEHAotnFiH6ecFD6xf_9x33_fMRkqa3_KE8NZM7vmvNgElox2UvcP_2K5E7jOdL2XQdJCTIW3Qlj66yE2a84SYlbvxIc4hDrIog0XNt4FhavvshxxUIfDQo6Q8qXDR5v7nwt6SCopYC3t3KVRdJh08GzKoVxysd7afJjxXxx178gY29uMRqnwxFN1OGnWaiBr-xGKb1frJ6jOI1zvuuCaljZ4aZjc9vOR4y9ZmobgrzkMFnpDAmQZ7MWcVMyodRMOA2dEOckywPhg-dIVNiVIqzJqe5Yg1ilNookjwtqj2TpNU7Z9gPqzYB73PmQ2p5LMDheAPxcOmEQ\",\"e\":\"AQAB\",\"use\":\"sig\",\"kid\":\"e3be37177a7c42bcbadd7cc63715f216\",\"qi\":\"r--nAtaYPAgJq_8R1-kynpd53E17n-loDUgtVWBCx_RmdORX4Auilv1S83dD1mbcnYCbV_LmxiEjOiz-4gS_E0qVGqakAqQrO1hVUvJa_Y2uftDgwFmuJNGbpRU-K4Td_uUzdm48za8yJCgOdYsWp6PNMCcmQgiInzkR3XYV83I\",\"dp\":\"oQUcvmMSw8gzdin-IB2xW_MLecAVEgLu0dGBdD6N8HbKZQvub_xm0dAfFtnvvWXDAFwFyhR96i-uXX67Bos_Q9-6KSAE4E0KGmDucDESfPOw-QJREbl0QgOD1gLQfVGtVy6SCR0TR2zNXFWtP7bD3MNoSXdEOr5fI97CGSNaBWM\",\"alg\":\"RS256\",\"dq\":\"DM-WJDy10-dkMu6MpgQEXEcxHtnA5rgSODD7SaVUFaHWLSbjScQslu2SuUCO5y7GxG0_0spklzb2-356FE98BPI7a4Oqj_COEYLSXzLCS45XeN1s80utL5Vwp4eeYo0RJCQ_nDBA76iEmxp5qHWmn5f25-FQykfXUrdYZj1V8SE\",\"n\":\"sa6m2i-iNvj6ZSTdSHZaBrnv6DId4AqAXhOyl0yA5fNWYe6r51h24SXqk7DsGYHHh74ii74tP1lTpmy6RD67tCK-tbN-d6yc4Z6FfM8R83v2QZUfaAixgHGtw0n2toqsiHf6EloDV-B8q4GYyKDD6cLecoaIuTmMBTY3kts59U2t9W10YoLGsmFqLSz8qNF5HkahzB6_--2DiBfVGUKAXHC-SICGZCi-8efOetv6pt9vFiWEgwU_DgjRNYzLFt1SEmbGFUU4kbjQ7tNTMkHfzfwcT6qLt4kVKy2FNYsEMk24keWtCvW_RyO_fisZc0W9smX7WtYjEXhcAjDeqHgEZw\"}")
@Property(name = "jwk.secondary", value = "{\"p\":\"4qJ9RNlu6SuDT_MLArfzimvKEwmet_j12Z9EQeb5nMjZIOHTcWw__duebUytfWwxsRHhtSVXeMt-EryQAOulm2p1bfiVuparq93z9P5cPnb0oArFaw3eFNFEmX5U-lY8PzUTTsFxO4aVQYAKXD6DP7p5uPzuwpHFuNc71nNIXZE\",\"kty\":\"RSA\",\"q\":\"v4OhkWMbS_nq77HFanwZAT_obfJuQfOFOQBORL4ATAHGUXm2y4YqLNExZs7Wj1MA_6ya6Y00s2JBM7fWq_fPe4d9xo5aGrPdcp0G8W21kkfh9vuVPlHVQTgSP7FQ9qahvXxNwK_11yNr3p1HBmScJ5mHlMBpIJsFcvHA-uXe0Ps\",\"d\":\"EunrjnQ1-jJPSCrt2L94PUpDrakup8a4pXys52YSkJY-W6XidM0roOS6kr06P3G6VQgc6AL_BkvTQ_XS0oXHbXVprDQ5Syam5p9oxHBhhW_vSqIMgUOfm28uyB3Mtw9rBxdUxW3yElHioaR8a-exYhhyVXb1QEhxL_rcnthmhAkM2NcHi2UnxGKFTsC0abQ2MuQc1OAuW5veDiIF2hfdC41qE0_d8vB6FDWbblgUpbwB6uSZaViPs15Buq2oX9dCCw54-PgzkfehDt7lyqgupktbV1psnVVhL86shzt4QFnhd3k7VpFbjCNFtiJTrufV-XBWT0pl2w3VR9wrHJ1bYQ\",\"e\":\"AQAB\",\"use\":\"sig\",\"kid\":\"0794e938379540dc8eaa559508524a79\",\"qi\":\"jy-TNyXVy_44_n4KGAwIbZO2C4r6uNWuEdehBfQKkPhiP90myG1KZVfOoKNOK9bCv2mvZJcBz4c1ArElgpuSCV4-KFac1ZzQo_ic5aoIej8Qa80y2ogc-_Yv6_ZLHC1S76M-lm4jayk2-rvuBpy2pUvHbW6Srhs_szwz7ZfSkLg\",\"dp\":\"ApqdV9ortRAj7Ro8ySY17SQ56SgWI8T_hiWXUi6GNa_1FrShik8VGSSZ2GWmJKfGlmM_NaadL60e4LY77VbHy1ZYzQ-rIL60cEAXmnwFsU4Kl4AoLoe1QoX5BM53yXyOKqfAdgow898i_eKru82YEnZhCagWUjP8kpgefuNKNJE\",\"alg\":\"RS256\",\"dq\":\"bFF78WoXh0pMCdQHL2oPDnjh8kWa_OxKHmpA2nqIWnTqgSyRKd2xPvX2tgooqpmsx-8NEymNdCQPcrv4y_z2OgzxI3tiFRZEGs4bnjOJ7bmAYZv71mqcbi3TjHiyrT6j3jNPGrurFUpweVGFWWVQOMmKOKT3ELz9QPzhREb9Vj8\",\"n\":\"qYvDpV8DRU5hx9eXpE4Ms8nUXicEwrxUUz5gb5gkXpIeY82mqfQKKCP6PSFnkKYtRFTOUSm9cgGGfOd7O4NFsIsxLwXCj34X7ORr19eXKBLvG3bZJLxqRlbYuQshDMkQOui1sDBxvYnj5p4iHne6l2btH5grHOCShUWG-bKps5Y8bKNHod1pIOOBabVCmn3sUVUkZw8nyXkQqZbv-c8x6z0TEfhNOPOIt2AmmlNgrE_8g7-dnCvqfJnhv0c7qkOJzsb7OMmvVwsQNiM59D6uaWZr-vdANo6NggiZmCKUS3tpUvdXW7ec9WMPJWhrVEkRcbWXQnZ_C7pXFrz7rLeNKw\"}")
@MicronautTest(startApplication = false)
class ValidateSecondarySignedJwtTest {

    @Inject
    lateinit var claimsGenerator: ClaimsGenerator

    @Inject
    lateinit var jwkConfiguration: JwkConfiguration

    @Inject
    lateinit var tokenValidator: TokenValidator

    @Test
    fun canValidateAJWebTokenSignedWithTheSecondaryJsonWebKey() {

        val signatureGeneratorConfiguration: SignatureGeneratorConfiguration = RSASignatureGenerator(MockSignatureGenerator(jwkConfiguration))
        val tokenGenerator: TokenGenerator = JwtTokenGenerator(signatureGeneratorConfiguration, null, claimsGenerator)
        val jwtOptional = tokenGenerator.generateToken(mapOf("sub" to "sergio"))
        assertTrue(jwtOptional.isPresent)

        val jwtString = jwtOptional.get()
        assertDoesNotThrow<JWT> { JWTParser.parse(jwtString) }

        val jwt = JWTParser.parse(jwtString)
        assertTrue(jwt is SignedJWT)

        tokenValidator.validateToken(jwtString, null)
    }

    internal class MockSignatureGenerator(jwkConfiguration: JwkConfiguration) :
            AbstractRSAGeneratorSignatureConfiguration(jwkConfiguration.secondary)
}
1 See how to generate a JSON Web Key in the guide: JWK generation with a Micronaut command line application

5.3. Keys test

Create a test to verify that the application exposes a keys endpoint:

src/test/kotlin/example/micronaut/KeysTest.kt
package example.micronaut

import io.micronaut.context.annotation.Property
import io.micronaut.http.HttpRequest
import io.micronaut.http.HttpResponse
import io.micronaut.http.client.HttpClient
import io.micronaut.http.client.annotation.Client
import io.micronaut.test.extensions.junit5.annotation.MicronautTest
import jakarta.inject.Inject
import org.junit.jupiter.api.Assertions.assertDoesNotThrow
import org.junit.jupiter.api.Test

(1)
@Property(name = "jwk.primary", value = "{\"p\":\"_OZyH1Mk3wR0oXw1C31t4kWOcaHFB6Njro1cYx52REnPiznn_JTtwvlAMpvV6LVCIZPgKMzdIEMY1gYs1LsO-5IFqWwegXmYJ0iKXbRrZshfWBCzRLK3QK5fER1le1XUBDhtDk7KIW_Xg-SZF4pf_LUEVKMnyUpspGI5F77jlJ8\",\"kty\":\"RSA\",\"q\":\"s9wvl7z8vkHQvo9xOUp-z0a2Z7LFBDil2uIjPh1FQzs34gFXH8dQPRox83TuN5d4KzdLPqQNQAfMXU9_KmxihNb_qDQahYugeELmcem04munxXqBdyZqWhWCy5YmujYqn44irwvoTbw6_RkMqjCmINPTPadptlPivsZ6RhKn8zk\",\"d\":\"ok3wmhOy8NZEHAotnFiH6ecFD6xf_9x33_fMRkqa3_KE8NZM7vmvNgElox2UvcP_2K5E7jOdL2XQdJCTIW3Qlj66yE2a84SYlbvxIc4hDrIog0XNt4FhavvshxxUIfDQo6Q8qXDR5v7nwt6SCopYC3t3KVRdJh08GzKoVxysd7afJjxXxx178gY29uMRqnwxFN1OGnWaiBr-xGKb1frJ6jOI1zvuuCaljZ4aZjc9vOR4y9ZmobgrzkMFnpDAmQZ7MWcVMyodRMOA2dEOckywPhg-dIVNiVIqzJqe5Yg1ilNookjwtqj2TpNU7Z9gPqzYB73PmQ2p5LMDheAPxcOmEQ\",\"e\":\"AQAB\",\"use\":\"sig\",\"kid\":\"e3be37177a7c42bcbadd7cc63715f216\",\"qi\":\"r--nAtaYPAgJq_8R1-kynpd53E17n-loDUgtVWBCx_RmdORX4Auilv1S83dD1mbcnYCbV_LmxiEjOiz-4gS_E0qVGqakAqQrO1hVUvJa_Y2uftDgwFmuJNGbpRU-K4Td_uUzdm48za8yJCgOdYsWp6PNMCcmQgiInzkR3XYV83I\",\"dp\":\"oQUcvmMSw8gzdin-IB2xW_MLecAVEgLu0dGBdD6N8HbKZQvub_xm0dAfFtnvvWXDAFwFyhR96i-uXX67Bos_Q9-6KSAE4E0KGmDucDESfPOw-QJREbl0QgOD1gLQfVGtVy6SCR0TR2zNXFWtP7bD3MNoSXdEOr5fI97CGSNaBWM\",\"alg\":\"RS256\",\"dq\":\"DM-WJDy10-dkMu6MpgQEXEcxHtnA5rgSODD7SaVUFaHWLSbjScQslu2SuUCO5y7GxG0_0spklzb2-356FE98BPI7a4Oqj_COEYLSXzLCS45XeN1s80utL5Vwp4eeYo0RJCQ_nDBA76iEmxp5qHWmn5f25-FQykfXUrdYZj1V8SE\",\"n\":\"sa6m2i-iNvj6ZSTdSHZaBrnv6DId4AqAXhOyl0yA5fNWYe6r51h24SXqk7DsGYHHh74ii74tP1lTpmy6RD67tCK-tbN-d6yc4Z6FfM8R83v2QZUfaAixgHGtw0n2toqsiHf6EloDV-B8q4GYyKDD6cLecoaIuTmMBTY3kts59U2t9W10YoLGsmFqLSz8qNF5HkahzB6_--2DiBfVGUKAXHC-SICGZCi-8efOetv6pt9vFiWEgwU_DgjRNYzLFt1SEmbGFUU4kbjQ7tNTMkHfzfwcT6qLt4kVKy2FNYsEMk24keWtCvW_RyO_fisZc0W9smX7WtYjEXhcAjDeqHgEZw\"}")
@Property(name = "jwk.secondary", value = "{\"p\":\"4qJ9RNlu6SuDT_MLArfzimvKEwmet_j12Z9EQeb5nMjZIOHTcWw__duebUytfWwxsRHhtSVXeMt-EryQAOulm2p1bfiVuparq93z9P5cPnb0oArFaw3eFNFEmX5U-lY8PzUTTsFxO4aVQYAKXD6DP7p5uPzuwpHFuNc71nNIXZE\",\"kty\":\"RSA\",\"q\":\"v4OhkWMbS_nq77HFanwZAT_obfJuQfOFOQBORL4ATAHGUXm2y4YqLNExZs7Wj1MA_6ya6Y00s2JBM7fWq_fPe4d9xo5aGrPdcp0G8W21kkfh9vuVPlHVQTgSP7FQ9qahvXxNwK_11yNr3p1HBmScJ5mHlMBpIJsFcvHA-uXe0Ps\",\"d\":\"EunrjnQ1-jJPSCrt2L94PUpDrakup8a4pXys52YSkJY-W6XidM0roOS6kr06P3G6VQgc6AL_BkvTQ_XS0oXHbXVprDQ5Syam5p9oxHBhhW_vSqIMgUOfm28uyB3Mtw9rBxdUxW3yElHioaR8a-exYhhyVXb1QEhxL_rcnthmhAkM2NcHi2UnxGKFTsC0abQ2MuQc1OAuW5veDiIF2hfdC41qE0_d8vB6FDWbblgUpbwB6uSZaViPs15Buq2oX9dCCw54-PgzkfehDt7lyqgupktbV1psnVVhL86shzt4QFnhd3k7VpFbjCNFtiJTrufV-XBWT0pl2w3VR9wrHJ1bYQ\",\"e\":\"AQAB\",\"use\":\"sig\",\"kid\":\"0794e938379540dc8eaa559508524a79\",\"qi\":\"jy-TNyXVy_44_n4KGAwIbZO2C4r6uNWuEdehBfQKkPhiP90myG1KZVfOoKNOK9bCv2mvZJcBz4c1ArElgpuSCV4-KFac1ZzQo_ic5aoIej8Qa80y2ogc-_Yv6_ZLHC1S76M-lm4jayk2-rvuBpy2pUvHbW6Srhs_szwz7ZfSkLg\",\"dp\":\"ApqdV9ortRAj7Ro8ySY17SQ56SgWI8T_hiWXUi6GNa_1FrShik8VGSSZ2GWmJKfGlmM_NaadL60e4LY77VbHy1ZYzQ-rIL60cEAXmnwFsU4Kl4AoLoe1QoX5BM53yXyOKqfAdgow898i_eKru82YEnZhCagWUjP8kpgefuNKNJE\",\"alg\":\"RS256\",\"dq\":\"bFF78WoXh0pMCdQHL2oPDnjh8kWa_OxKHmpA2nqIWnTqgSyRKd2xPvX2tgooqpmsx-8NEymNdCQPcrv4y_z2OgzxI3tiFRZEGs4bnjOJ7bmAYZv71mqcbi3TjHiyrT6j3jNPGrurFUpweVGFWWVQOMmKOKT3ELz9QPzhREb9Vj8\",\"n\":\"qYvDpV8DRU5hx9eXpE4Ms8nUXicEwrxUUz5gb5gkXpIeY82mqfQKKCP6PSFnkKYtRFTOUSm9cgGGfOd7O4NFsIsxLwXCj34X7ORr19eXKBLvG3bZJLxqRlbYuQshDMkQOui1sDBxvYnj5p4iHne6l2btH5grHOCShUWG-bKps5Y8bKNHod1pIOOBabVCmn3sUVUkZw8nyXkQqZbv-c8x6z0TEfhNOPOIt2AmmlNgrE_8g7-dnCvqfJnhv0c7qkOJzsb7OMmvVwsQNiM59D6uaWZr-vdANo6NggiZmCKUS3tpUvdXW7ec9WMPJWhrVEkRcbWXQnZ_C7pXFrz7rLeNKw\"}")
@MicronautTest
class KeysTest {

    @Inject
    @field:Client("/")
    lateinit var httpClient: HttpClient

    @Test
    fun whenYouDefineABeanOfTypeJwkProviderThenTheKeysEndpointIsExposed() {
        assertDoesNotThrow<HttpResponse<Any?>> {
            httpClient.toBlocking().exchange(HttpRequest.GET<Any>("/keys"))
        }
    }
}
1 See how to generate a JSON Web Key in the guide: JWK generation with a Micronaut command line application

6. Refresh endpoint

The refresh endpoint refreshes the application state, causing all Refreshable beans in the context to be destroyed and reinstantiated upon further requests. This is accomplished by publishing a RefreshEvent in the Application Context.

You can use support for distributed configuration in the Micronaut framework to fetch the JSON Web Keys from a secret repository such as HashiCorp Vault or AWS Secrets Manager. Set a rotation policy and hit the refresh endpoint to reload configuration upon keys' rotation.

Enable the Refresh Endpoint:

src/main/resources/application.yml
endpoints:
  refresh:
    enabled: true (1)
    sensitive: false (2)
1 Enable the Refresh Endpoint
2 Set the endpoint as non sensitive. Learn more about Built-In Endpoints Security.

7. Testing the Application

To run the tests:

./mvnw test

8. Running the Application

To run the application, use the ./mvnw mn:run command, which starts the application on port 8080.

9. Invoke the keys endpoint

Create two environment variables with Json Web Keys

export JWK_PRIMARY="{\"p\":\"_OZyH1Mk3wR0oXw1C31t4kWOcaHFB6Njro1cYx52REnPiznn_JTtwvlAMpvV6LVCIZPgKMzdIEMY1gYs1LsO-5IFqWwegXmYJ0iKXbRrZshfWBCzRLK3QK5fER1le1XUBDhtDk7KIW_Xg-SZF4pf_LUEVKMnyUpspGI5F77jlJ8\",\"kty\":\"RSA\",\"q\":\"s9wvl7z8vkHQvo9xOUp-z0a2Z7LFBDil2uIjPh1FQzs34gFXH8dQPRox83TuN5d4KzdLPqQNQAfMXU9_KmxihNb_qDQahYugeELmcem04munxXqBdyZqWhWCy5YmujYqn44irwvoTbw6_RkMqjCmINPTPadptlPivsZ6RhKn8zk\",\"d\":\"ok3wmhOy8NZEHAotnFiH6ecFD6xf_9x33_fMRkqa3_KE8NZM7vmvNgElox2UvcP_2K5E7jOdL2XQdJCTIW3Qlj66yE2a84SYlbvxIc4hDrIog0XNt4FhavvshxxUIfDQo6Q8qXDR5v7nwt6SCopYC3t3KVRdJh08GzKoVxysd7afJjxXxx178gY29uMRqnwxFN1OGnWaiBr-xGKb1frJ6jOI1zvuuCaljZ4aZjc9vOR4y9ZmobgrzkMFnpDAmQZ7MWcVMyodRMOA2dEOckywPhg-dIVNiVIqzJqe5Yg1ilNookjwtqj2TpNU7Z9gPqzYB73PmQ2p5LMDheAPxcOmEQ\",\"e\":\"AQAB\",\"use\":\"sig\",\"kid\":\"e3be37177a7c42bcbadd7cc63715f216\",\"qi\":\"r--nAtaYPAgJq_8R1-kynpd53E17n-loDUgtVWBCx_RmdORX4Auilv1S83dD1mbcnYCbV_LmxiEjOiz-4gS_E0qVGqakAqQrO1hVUvJa_Y2uftDgwFmuJNGbpRU-K4Td_uUzdm48za8yJCgOdYsWp6PNMCcmQgiInzkR3XYV83I\",\"dp\":\"oQUcvmMSw8gzdin-IB2xW_MLecAVEgLu0dGBdD6N8HbKZQvub_xm0dAfFtnvvWXDAFwFyhR96i-uXX67Bos_Q9-6KSAE4E0KGmDucDESfPOw-QJREbl0QgOD1gLQfVGtVy6SCR0TR2zNXFWtP7bD3MNoSXdEOr5fI97CGSNaBWM\",\"alg\":\"RS256\",\"dq\":\"DM-WJDy10-dkMu6MpgQEXEcxHtnA5rgSODD7SaVUFaHWLSbjScQslu2SuUCO5y7GxG0_0spklzb2-356FE98BPI7a4Oqj_COEYLSXzLCS45XeN1s80utL5Vwp4eeYo0RJCQ_nDBA76iEmxp5qHWmn5f25-FQykfXUrdYZj1V8SE\",\"n\":\"sa6m2i-iNvj6ZSTdSHZaBrnv6DId4AqAXhOyl0yA5fNWYe6r51h24SXqk7DsGYHHh74ii74tP1lTpmy6RD67tCK-tbN-d6yc4Z6FfM8R83v2QZUfaAixgHGtw0n2toqsiHf6EloDV-B8q4GYyKDD6cLecoaIuTmMBTY3kts59U2t9W10YoLGsmFqLSz8qNF5HkahzB6_--2DiBfVGUKAXHC-SICGZCi-8efOetv6pt9vFiWEgwU_DgjRNYzLFt1SEmbGFUU4kbjQ7tNTMkHfzfwcT6qLt4kVKy2FNYsEMk24keWtCvW_RyO_fisZc0W9smX7WtYjEXhcAjDeqHgEZw\"}"
export JWK_SECONDARY="{\"p\":\"4qJ9RNlu6SuDT_MLArfzimvKEwmet_j12Z9EQeb5nMjZIOHTcWw__duebUytfWwxsRHhtSVXeMt-EryQAOulm2p1bfiVuparq93z9P5cPnb0oArFaw3eFNFEmX5U-lY8PzUTTsFxO4aVQYAKXD6DP7p5uPzuwpHFuNc71nNIXZE\",\"kty\":\"RSA\",\"q\":\"v4OhkWMbS_nq77HFanwZAT_obfJuQfOFOQBORL4ATAHGUXm2y4YqLNExZs7Wj1MA_6ya6Y00s2JBM7fWq_fPe4d9xo5aGrPdcp0G8W21kkfh9vuVPlHVQTgSP7FQ9qahvXxNwK_11yNr3p1HBmScJ5mHlMBpIJsFcvHA-uXe0Ps\",\"d\":\"EunrjnQ1-jJPSCrt2L94PUpDrakup8a4pXys52YSkJY-W6XidM0roOS6kr06P3G6VQgc6AL_BkvTQ_XS0oXHbXVprDQ5Syam5p9oxHBhhW_vSqIMgUOfm28uyB3Mtw9rBxdUxW3yElHioaR8a-exYhhyVXb1QEhxL_rcnthmhAkM2NcHi2UnxGKFTsC0abQ2MuQc1OAuW5veDiIF2hfdC41qE0_d8vB6FDWbblgUpbwB6uSZaViPs15Buq2oX9dCCw54-PgzkfehDt7lyqgupktbV1psnVVhL86shzt4QFnhd3k7VpFbjCNFtiJTrufV-XBWT0pl2w3VR9wrHJ1bYQ\",\"e\":\"AQAB\",\"use\":\"sig\",\"kid\":\"0794e938379540dc8eaa559508524a79\",\"qi\":\"jy-TNyXVy_44_n4KGAwIbZO2C4r6uNWuEdehBfQKkPhiP90myG1KZVfOoKNOK9bCv2mvZJcBz4c1ArElgpuSCV4-KFac1ZzQo_ic5aoIej8Qa80y2ogc-_Yv6_ZLHC1S76M-lm4jayk2-rvuBpy2pUvHbW6Srhs_szwz7ZfSkLg\",\"dp\":\"ApqdV9ortRAj7Ro8ySY17SQ56SgWI8T_hiWXUi6GNa_1FrShik8VGSSZ2GWmJKfGlmM_NaadL60e4LY77VbHy1ZYzQ-rIL60cEAXmnwFsU4Kl4AoLoe1QoX5BM53yXyOKqfAdgow898i_eKru82YEnZhCagWUjP8kpgefuNKNJE\",\"alg\":\"RS256\",\"dq\":\"bFF78WoXh0pMCdQHL2oPDnjh8kWa_OxKHmpA2nqIWnTqgSyRKd2xPvX2tgooqpmsx-8NEymNdCQPcrv4y_z2OgzxI3tiFRZEGs4bnjOJ7bmAYZv71mqcbi3TjHiyrT6j3jNPGrurFUpweVGFWWVQOMmKOKT3ELz9QPzhREb9Vj8\",\"n\":\"qYvDpV8DRU5hx9eXpE4Ms8nUXicEwrxUUz5gb5gkXpIeY82mqfQKKCP6PSFnkKYtRFTOUSm9cgGGfOd7O4NFsIsxLwXCj34X7ORr19eXKBLvG3bZJLxqRlbYuQshDMkQOui1sDBxvYnj5p4iHne6l2btH5grHOCShUWG-bKps5Y8bKNHod1pIOOBabVCmn3sUVUkZw8nyXkQqZbv-c8x6z0TEfhNOPOIt2AmmlNgrE_8g7-dnCvqfJnhv0c7qkOJzsb7OMmvVwsQNiM59D6uaWZr-vdANo6NggiZmCKUS3tpUvdXW7ec9WMPJWhrVEkRcbWXQnZ_C7pXFrz7rLeNKw\"}"

Invoke the /keys endpoint:

curl -i localhost:8080/keys
HTTP/1.1 200 OK
Date: Mon, 7 Jun 2021 14:42:42 GMT
content-type: application/json
content-length: 892
connection: keep-alive

{"keys":[{"kty":"RSA","e":"AQAB","use":"sig","kid":"e3be37177a7c42bcbadd7cc63715f216","alg":"RS256","n":"sa6m2i-iNvj6ZSTdSHZaBrnv6DId4AqAXhOyl0yA5fNWYe6r51h24SXqk7DsGYHHh74ii74tP1lTpmy6RD67tCK-tbN-d6yc4Z6FfM8R83v2QZUfaAixgHGtw0n2toqsiHf6EloDV-B8q4GYyKDD6cLecoaIuTmMBTY3kts59U2t9W10YoLGsmFqLSz8qNF5HkahzB6_--2DiBfVGUKAXHC-SICGZCi-8efOetv6pt9vFiWEgwU_DgjRNYzLFt1SEmbGFUU4kbjQ7tNTMkHfzfwcT6qLt4kVKy2FNYsEMk24keWtCvW_RyO_fisZc0W9smX7WtYjEXhcAjDeqHgEZw"},{"kty":"RSA","e":"AQAB","use":"sig","kid":"0794e938379540dc8eaa559508524a79","alg":"RS256","n":"qYvDpV8DRU5hx9eXpE4Ms8nUXicEwrxUUz5gb5gkXpIeY82mqfQKKCP6PSFnkKYtRFTOUSm9cgGGfOd7O4NFsIsxLwXCj34X7ORr19eXKBLvG3bZJLxqRlbYuQshDMkQOui1sDBxvYnj5p4iHne6l2btH5grHOCShUWG-bKps5Y8bKNHod1pIOOBabVCmn3sUVUkZw8nyXkQqZbv-c8x6z0TEfhNOPOIt2AmmlNgrE_8g7-dnCvqfJnhv0c7qkOJzsb7OMmvVwsQNiM59D6uaWZr-vdANo6NggiZmCKUS3tpUvdXW7ec9WMPJWhrVEkRcbWXQnZ_C7pXFrz7rLeNKw"}]}

10. Generate a Micronaut Application Native Executable with GraalVM

We will use GraalVM, the polyglot embeddable virtual machine, to generate a native executable of our Micronaut application.

Compiling native executables ahead of time with GraalVM improves startup time and reduces the memory footprint of JVM-based applications.

Only Java and Kotlin projects support using GraalVM’s native-image tool. Groovy relies heavily on reflection, which is only partially supported by GraalVM.

10.1. Native executable generation

The easiest way to install GraalVM on Linux or Mac is to use SDKMan.io.

Java 11
sdk install java 22.3.r11-grl
If you still use Java 8, use the JDK11 version of GraalVM.
Java 17
sdk install java 22.3.r17-grl

For installation on Windows, or for manual installation on Linux or Mac, see the GraalVM Getting Started documentation.

After installing GraalVM, install the native-image component, which is not installed by default:

gu install native-image

To generate a native executable using Maven, run:

./mvnw package -Dpackaging=native-image

The native executable is created in the target directory and can be run with target/micronautguide.

Invoke the keys endpoint as described in the previous section

11. Next steps

Explore more features with Micronaut Guides.

Read more about Micronaut Security.

Check out the guide JWK Generation with a Micronaut Command Line Application.

12. Help with the Micronaut Framework

The Micronaut Foundation sponsored the creation of this Guide. A variety of consulting and support services are available.