Just use the attached project. It uses the google endpoint as the jkws endpoint ( https://www.googleapis.com/oauth2/v3/certs ). The test should return null (not validated cos the key was not found). But it fails with a exception decoding the keys from google. The test uses last wildfly-elytron 1.15.3.Final. cd jkw-elytron-test mvn clean test ... Running com.redhat.sample.JwkManagerTest Mar 29, 2021 11:06:36 AM org.wildfly.security.auth.realm.token.validator.JwtValidator <init> WARN: ELY01126: Jwt-based token realm not configured with a list of valid issuers. Ignoring issuer verification. Mar 29, 2021 11:06:36 AM org.wildfly.security.auth.realm.token.validator.JwtValidator <init> WARN: ELY01127: Jwt-based token not configured with a list of valid audiences. Ignoring audience verification. Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.707 sec <<< FAILURE! testGoogleApiKeys(com.redhat.sample.JwkManagerTest) Time elapsed: 0.676 sec <<< ERROR! java.lang.IllegalStateException: ELY01116: Signature verification failed at org.wildfly.security.auth.realm.token.validator.JwtValidator.verifySignature(JwtValidator.java:188) at org.wildfly.security.auth.realm.token.validator.JwtValidator.validate(JwtValidator.java:127) at com.redhat.sample.JwkManagerTest.testGoogleApiKeys(JwkManagerTest.java:95) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.junit.runners.model.FrameworkMethod.runReflectiveCall(FrameworkMethod.java:59) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.junit.runners.ParentRunner.evaluate(ParentRunner.java:306) at org.junit.runners.BlockJUnit4ClassRunner.evaluate(BlockJUnit4ClassRunner.java:100) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63) at org.junit.runners.ParentRunner.run(ParentRunner.java:331) at org.junit.runners.ParentRunner.schedule(ParentRunner.java:79) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329) at org.junit.runners.ParentRunner.access(ParentRunner.java:66) at org.junit.runners.ParentRunner.evaluate(ParentRunner.java:293) at org.junit.runners.ParentRunner.evaluate(ParentRunner.java:306) at org.junit.runners.ParentRunner.run(ParentRunner.java:413) at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:252) at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:141) at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:112) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189) at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165) at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85) at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:115) at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:75) Caused by: java.lang.IllegalArgumentException: Illegal base64 character 5f at java.util.BaseDecoder.decode0(Base64.java:714) at java.util.BaseDecoder.decode(Base64.java:526) at java.util.BaseDecoder.decode(Base64.java:549) at org.wildfly.security.auth.realm.token.validator.JwkManager.getJwksFromUrl(JwkManager.java:178) at org.wildfly.security.auth.realm.token.validator.JwkManager.checkRemote(JwkManager.java:110) at org.wildfly.security.auth.realm.token.validator.JwkManager.getPublicKey(JwkManager.java:75) at org.wildfly.security.auth.realm.token.validator.JwtValidator.resolvePublicKey(JwtValidator.java:300) at org.wildfly.security.auth.realm.token.validator.JwtValidator.createSignature(JwtValidator.java:248) at org.wildfly.security.auth.realm.token.validator.JwtValidator.verifySignature(JwtValidator.java:179) ... 34 more