Multiple JWS Algorithms

Fixes: gh-6883

oauth2/oauth2-jose/src/main/java/org/springframework/security/oauth2/jwt/JWSAlgorithmMapJWSKeySelector.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2002-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.oauth2.jwt;
+
+import java.security.Key;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import com.nimbusds.jose.JWSAlgorithm;
+import com.nimbusds.jose.JWSHeader;
+import com.nimbusds.jose.KeySourceException;
+import com.nimbusds.jose.proc.JWSKeySelector;
+import com.nimbusds.jose.proc.SecurityContext;
+
+/**
+ * Class for delegating to a Nimbus JWSKeySelector by the given JWSAlgorithm
+ *
+ * @author Josh Cummings
+ */
+class JWSAlgorithmMapJWSKeySelector<C extends SecurityContext> implements JWSKeySelector<C> {
+	private Map<JWSAlgorithm, JWSKeySelector<C>> jwsKeySelectors;
+
+	JWSAlgorithmMapJWSKeySelector(Map<JWSAlgorithm, JWSKeySelector<C>> jwsKeySelectors) {
+		this.jwsKeySelectors = jwsKeySelectors;
+	}
+
+	@Override
+	public List<? extends Key> selectJWSKeys(JWSHeader header, C context) throws KeySourceException {
+		JWSKeySelector<C> keySelector = this.jwsKeySelectors.get(header.getAlgorithm());
+		if (keySelector == null) {
+			throw new IllegalArgumentException("Unsupported algorithm of " + header.getAlgorithm());
+		}
+		return keySelector.selectJWSKeys(header, context);
+	}
+
+	public Set<JWSAlgorithm> getExpectedJWSAlgorithms() {
+		return this.jwsKeySelectors.keySet();
+	}
+}

oauth2/oauth2-jose/src/main/java/org/springframework/security/oauth2/jwt/NimbusJwtDecoder.java

@@ -23,8 +23,12 @@ import java.security.interfaces.RSAPublicKey;
 import java.text.ParseException;
 import java.time.Instant;
 import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.Set;
+import java.util.function.Consumer;
 import javax.crypto.SecretKey;
 
 import com.nimbusds.jose.JWSAlgorithm;
@@ -209,7 +213,7 @@ public final class NimbusJwtDecoder implements JwtDecoder {
 	 */
 	public static final class JwkSetUriJwtDecoderBuilder {
 		private String jwkSetUri;
-		private JWSAlgorithm jwsAlgorithm = JWSAlgorithm.RS256;
+		private Set<SignatureAlgorithm> signatureAlgorithms = new HashSet<>();
 		private RestOperations restOperations = new RestTemplate();
 
 		private JwkSetUriJwtDecoderBuilder(String jwkSetUri) {
@@ -218,15 +222,30 @@ public final class NimbusJwtDecoder implements JwtDecoder {
 		}
 
 		/**
-		 * Use the given signing
-		 * <a href="https://tools.ietf.org/html/rfc7515#section-4.1.1" target="_blank">algorithm</a>.
+		 * Append the given signing
+		 * <a href="https://tools.ietf.org/html/rfc7515#section-4.1.1" target="_blank">algorithm</a>
+		 * to the set of algorithms to use.
 		 *
 		 * @param signatureAlgorithm the algorithm to use
 		 * @return a {@link JwkSetUriJwtDecoderBuilder} for further configurations
 		 */
 		public JwkSetUriJwtDecoderBuilder jwsAlgorithm(SignatureAlgorithm signatureAlgorithm) {
 			Assert.notNull(signatureAlgorithm, "signatureAlgorithm cannot be null");
-			this.jwsAlgorithm = JWSAlgorithm.parse(signatureAlgorithm.getName());
+			this.signatureAlgorithms.add(signatureAlgorithm);
+			return this;
+		}
+
+		/**
+		 * Configure the list of
+		 * <a href="https://tools.ietf.org/html/rfc7515#section-4.1.1" target="_blank">algorithms</a>
+		 * to use with the given {@link Consumer}.
+		 *
+		 * @param signatureAlgorithmsConsumer a {@link Consumer} for further configuring the algorithm list
+		 * @return a {@link JwkSetUriJwtDecoderBuilder} for further configurations
+		 */
+		public JwkSetUriJwtDecoderBuilder jwsAlgorithms(Consumer<Set<SignatureAlgorithm>> signatureAlgorithmsConsumer) {
+			Assert.notNull(signatureAlgorithmsConsumer, "signatureAlgorithmsConsumer cannot be null");
+			signatureAlgorithmsConsumer.accept(this.signatureAlgorithms);
 			return this;
 		}
 
@@ -245,13 +264,27 @@ public final class NimbusJwtDecoder implements JwtDecoder {
 			return this;
 		}
 
+		JWSKeySelector<SecurityContext> jwsKeySelector(JWKSource<SecurityContext> jwkSource) {
+			if (this.signatureAlgorithms.isEmpty()) {
+				return new JWSVerificationKeySelector<>(JWSAlgorithm.RS256, jwkSource);
+			} else if (this.signatureAlgorithms.size() == 1) {
+				JWSAlgorithm jwsAlgorithm = JWSAlgorithm.parse(this.signatureAlgorithms.iterator().next().getName());
+				return new JWSVerificationKeySelector<>(jwsAlgorithm, jwkSource);
+			} else {
+				Map<JWSAlgorithm, JWSKeySelector<SecurityContext>> jwsKeySelectors = new HashMap<>();
+				for (SignatureAlgorithm signatureAlgorithm : this.signatureAlgorithms) {
+					JWSAlgorithm jwsAlg = JWSAlgorithm.parse(signatureAlgorithm.getName());
+					jwsKeySelectors.put(jwsAlg, new JWSVerificationKeySelector<>(jwsAlg, jwkSource));
+				}
+				return new JWSAlgorithmMapJWSKeySelector<>(jwsKeySelectors);
+			}
+		}
+
 		JWTProcessor<SecurityContext> processor() {
 			ResourceRetriever jwkSetRetriever = new RestOperationsResourceRetriever(this.restOperations);
 			JWKSource<SecurityContext> jwkSource = new RemoteJWKSet<>(toURL(this.jwkSetUri), jwkSetRetriever);
-			JWSKeySelector<SecurityContext> jwsKeySelector =
-					new JWSVerificationKeySelector<>(this.jwsAlgorithm, jwkSource);
 			ConfigurableJWTProcessor<SecurityContext> jwtProcessor = new DefaultJWTProcessor<>();
-			jwtProcessor.setJWSKeySelector(jwsKeySelector);
+			jwtProcessor.setJWSKeySelector(jwsKeySelector(jwkSource));
 
 			// Spring Security validates the claim set independent from Nimbus
 			jwtProcessor.setJWTClaimsSetVerifier((claims, context) -> { });

oauth2/oauth2-jose/src/main/java/org/springframework/security/oauth2/jwt/NimbusReactiveJwtDecoder.java

@@ -18,8 +18,12 @@ package org.springframework.security.oauth2.jwt;
 import java.security.interfaces.RSAPublicKey;
 import java.time.Instant;
 import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.Set;
+import java.util.function.Consumer;
 import java.util.function.Function;
 import javax.crypto.SecretKey;
 
@@ -31,6 +35,7 @@ import com.nimbusds.jose.jwk.JWK;
 import com.nimbusds.jose.jwk.JWKMatcher;
 import com.nimbusds.jose.jwk.JWKSelector;
 import com.nimbusds.jose.jwk.source.JWKSecurityContextJWKSet;
+import com.nimbusds.jose.jwk.source.JWKSource;
 import com.nimbusds.jose.proc.BadJOSEException;
 import com.nimbusds.jose.proc.JWKSecurityContext;
 import com.nimbusds.jose.proc.JWSKeySelector;
@@ -233,7 +238,7 @@ public final class NimbusReactiveJwtDecoder implements ReactiveJwtDecoder {
 	 */
 	public static final class JwkSetUriReactiveJwtDecoderBuilder {
 		private final String jwkSetUri;
-		private JWSAlgorithm jwsAlgorithm = JWSAlgorithm.RS256;
+		private Set<SignatureAlgorithm> signatureAlgorithms = new HashSet<>();
 		private WebClient webClient = WebClient.create();
 
 		private JwkSetUriReactiveJwtDecoderBuilder(String jwkSetUri) {
@@ -242,15 +247,30 @@ public final class NimbusReactiveJwtDecoder implements ReactiveJwtDecoder {
 		}
 
 		/**
-		 * Use the given signing
-		 * <a href="https://tools.ietf.org/html/rfc7515#section-4.1.1" target="_blank">algorithm</a>.
+		 * Append the given signing
+		 * <a href="https://tools.ietf.org/html/rfc7515#section-4.1.1" target="_blank">algorithm</a>
+		 * to the set of algorithms to use.
 		 *
 		 * @param signatureAlgorithm the algorithm to use
 		 * @return a {@link JwkSetUriReactiveJwtDecoderBuilder} for further configurations
 		 */
 		public JwkSetUriReactiveJwtDecoderBuilder jwsAlgorithm(SignatureAlgorithm signatureAlgorithm) {
 			Assert.notNull(signatureAlgorithm, "sig cannot be null");
-			this.jwsAlgorithm = JWSAlgorithm.parse(signatureAlgorithm.getName());
+			this.signatureAlgorithms.add(signatureAlgorithm);
+			return this;
+		}
+
+		/**
+		 * Configure the list of
+		 * <a href="https://tools.ietf.org/html/rfc7515#section-4.1.1" target="_blank">algorithms</a>
+		 * to use with the given {@link Consumer}.
+		 *
+		 * @param signatureAlgorithmsConsumer a {@link Consumer} for further configuring the algorithm list
+		 * @return a {@link JwkSetUriReactiveJwtDecoderBuilder} for further configurations
+		 */
+		public JwkSetUriReactiveJwtDecoderBuilder jwsAlgorithms(Consumer<Set<SignatureAlgorithm>> signatureAlgorithmsConsumer) {
+			Assert.notNull(signatureAlgorithmsConsumer, "signatureAlgorithmsConsumer cannot be null");
+			signatureAlgorithmsConsumer.accept(this.signatureAlgorithms);
 			return this;
 		}
 
@@ -278,28 +298,53 @@ public final class NimbusReactiveJwtDecoder implements ReactiveJwtDecoder {
 			return new NimbusReactiveJwtDecoder(processor());
 		}
 
+		JWSKeySelector<JWKSecurityContext> jwsKeySelector(JWKSource<JWKSecurityContext> jwkSource) {
+			if (this.signatureAlgorithms.isEmpty()) {
+				return new JWSVerificationKeySelector<>(JWSAlgorithm.RS256, jwkSource);
+			} else if (this.signatureAlgorithms.size() == 1) {
+				JWSAlgorithm jwsAlgorithm = JWSAlgorithm.parse(this.signatureAlgorithms.iterator().next().getName());
+				return new JWSVerificationKeySelector<>(jwsAlgorithm, jwkSource);
+			} else {
+				Map<JWSAlgorithm, JWSKeySelector<JWKSecurityContext>> jwsKeySelectors = new HashMap<>();
+				for (SignatureAlgorithm signatureAlgorithm : this.signatureAlgorithms) {
+					JWSAlgorithm jwsAlg = JWSAlgorithm.parse(signatureAlgorithm.getName());
+					jwsKeySelectors.put(jwsAlg, new JWSVerificationKeySelector<>(jwsAlg, jwkSource));
+				}
+				return new JWSAlgorithmMapJWSKeySelector<>(jwsKeySelectors);
+			}
+		}
+
 		Converter<JWT, Mono<JWTClaimsSet>> processor() {
 			JWKSecurityContextJWKSet jwkSource = new JWKSecurityContextJWKSet();
-
-			JWSKeySelector<JWKSecurityContext> jwsKeySelector =
-					new JWSVerificationKeySelector<>(this.jwsAlgorithm, jwkSource);
 			DefaultJWTProcessor<JWKSecurityContext> jwtProcessor = new DefaultJWTProcessor<>();
+			JWSKeySelector<JWKSecurityContext> jwsKeySelector = jwsKeySelector(jwkSource);
 			jwtProcessor.setJWSKeySelector(jwsKeySelector);
 			jwtProcessor.setJWTClaimsSetVerifier((claims, context) -> {});
 
 			ReactiveRemoteJWKSource source = new ReactiveRemoteJWKSource(this.jwkSetUri);
 			source.setWebClient(this.webClient);
 
+			Set<JWSAlgorithm> expectedJwsAlgorithms = getExpectedJwsAlgorithms(jwsKeySelector);
 			return jwt -> {
-				JWKSelector selector = createSelector(jwt.getHeader());
+				JWKSelector selector = createSelector(expectedJwsAlgorithms, jwt.getHeader());
 				return source.get(selector)
 						.onErrorMap(e -> new IllegalStateException("Could not obtain the keys", e))
 						.map(jwkList -> createClaimsSet(jwtProcessor, jwt, new JWKSecurityContext(jwkList)));
 			};
 		}
 
-		private JWKSelector createSelector(Header header) {
-			if (!this.jwsAlgorithm.equals(header.getAlgorithm())) {
+		private Set<JWSAlgorithm> getExpectedJwsAlgorithms(JWSKeySelector<?> jwsKeySelector) {
+			if (jwsKeySelector instanceof JWSVerificationKeySelector) {
+				return Collections.singleton(((JWSVerificationKeySelector<?>) jwsKeySelector).getExpectedJWSAlgorithm());
+			}
+			if (jwsKeySelector instanceof JWSAlgorithmMapJWSKeySelector) {
+				return ((JWSAlgorithmMapJWSKeySelector<?>) jwsKeySelector).getExpectedJWSAlgorithms();
+			}
+			throw new IllegalArgumentException("Unsupported key selector type " + jwsKeySelector.getClass());
+		}
+
+		private JWKSelector createSelector(Set<JWSAlgorithm> expectedJwsAlgorithms, Header header) {
+			if (!expectedJwsAlgorithms.contains(header.getAlgorithm())) {
 				throw new JwtException("Unsupported algorithm of " + header.getAlgorithm());
 			}
 

oauth2/oauth2-jose/src/test/java/org/springframework/security/oauth2/jwt/NimbusJwtDecoderTests.java

@@ -39,7 +39,10 @@ import com.nimbusds.jose.JWSHeader;
 import com.nimbusds.jose.JWSSigner;
 import com.nimbusds.jose.crypto.MACSigner;
 import com.nimbusds.jose.crypto.RSASSASigner;
+import com.nimbusds.jose.jwk.source.JWKSource;
 import com.nimbusds.jose.proc.BadJOSEException;
+import com.nimbusds.jose.proc.JWSKeySelector;
+import com.nimbusds.jose.proc.JWSVerificationKeySelector;
 import com.nimbusds.jose.proc.SecurityContext;
 import com.nimbusds.jwt.JWTClaimsSet;
 import com.nimbusds.jwt.SignedJWT;
@@ -357,6 +360,46 @@ public class NimbusJwtDecoderTests {
 				.isEqualTo("test-subject");
 	}
 
+	@Test
+	public void jwsKeySelectorWhenNoAlgorithmThenReturnsRS256Selector() {
+		JWKSource<SecurityContext> jwkSource = mock(JWKSource.class);
+		JWSKeySelector<SecurityContext> jwsKeySelector =
+				withJwkSetUri(JWK_SET_URI).jwsKeySelector(jwkSource);
+		assertThat(jwsKeySelector instanceof JWSVerificationKeySelector);
+		JWSVerificationKeySelector<?> jwsVerificationKeySelector =
+				(JWSVerificationKeySelector<?>) jwsKeySelector;
+		assertThat(jwsVerificationKeySelector.getExpectedJWSAlgorithm())
+				.isEqualTo(JWSAlgorithm.RS256);
+	}
+
+	@Test
+	public void jwsKeySelectorWhenOneAlgorithmThenReturnsSingleSelector() {
+		JWKSource<SecurityContext> jwkSource = mock(JWKSource.class);
+		JWSKeySelector<SecurityContext> jwsKeySelector =
+				withJwkSetUri(JWK_SET_URI).jwsAlgorithm(SignatureAlgorithm.RS512)
+						.jwsKeySelector(jwkSource);
+		assertThat(jwsKeySelector instanceof JWSVerificationKeySelector);
+		JWSVerificationKeySelector<?> jwsVerificationKeySelector =
+				(JWSVerificationKeySelector<?>) jwsKeySelector;
+		assertThat(jwsVerificationKeySelector.getExpectedJWSAlgorithm())
+				.isEqualTo(JWSAlgorithm.RS512);
+	}
+
+	@Test
+	public void jwsKeySelectorWhenMultipleAlgorithmThenReturnsCompositeSelector() {
+		JWKSource<SecurityContext> jwkSource = mock(JWKSource.class);
+		JWSKeySelector<SecurityContext> jwsKeySelector =
+				withJwkSetUri(JWK_SET_URI)
+						.jwsAlgorithm(SignatureAlgorithm.RS256)
+						.jwsAlgorithm(SignatureAlgorithm.RS512)
+						.jwsKeySelector(jwkSource);
+		assertThat(jwsKeySelector instanceof JWSAlgorithmMapJWSKeySelector);
+		JWSAlgorithmMapJWSKeySelector<?> jwsAlgorithmMapKeySelector =
+				(JWSAlgorithmMapJWSKeySelector<?>) jwsKeySelector;
+		assertThat(jwsAlgorithmMapKeySelector.getExpectedJWSAlgorithms())
+				.containsExactlyInAnyOrder(JWSAlgorithm.RS256, JWSAlgorithm.RS512);
+	}
+
 	private RSAPublicKey key() throws InvalidKeySpecException {
 		byte[] decoded = Base64.getDecoder().decode(VERIFY_KEY.getBytes());
 		EncodedKeySpec spec = new X509EncodedKeySpec(decoded);

oauth2/oauth2-jose/src/test/java/org/springframework/security/oauth2/jwt/NimbusReactiveJwtDecoderTests.java

@@ -16,11 +16,30 @@
 
 package org.springframework.security.oauth2.jwt;
 
+import java.net.UnknownHostException;
+import java.security.KeyFactory;
+import java.security.NoSuchAlgorithmException;
+import java.security.interfaces.RSAPublicKey;
+import java.security.spec.EncodedKeySpec;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.X509EncodedKeySpec;
+import java.text.ParseException;
+import java.time.Instant;
+import java.util.Base64;
+import java.util.Collections;
+import java.util.Date;
+import java.util.Map;
+import javax.crypto.SecretKey;
+
 import com.nimbusds.jose.JWSAlgorithm;
 import com.nimbusds.jose.JWSHeader;
 import com.nimbusds.jose.JWSSigner;
 import com.nimbusds.jose.crypto.MACSigner;
 import com.nimbusds.jose.jwk.JWKSet;
+import com.nimbusds.jose.jwk.source.JWKSource;
+import com.nimbusds.jose.proc.JWKSecurityContext;
+import com.nimbusds.jose.proc.JWSKeySelector;
+import com.nimbusds.jose.proc.JWSVerificationKeySelector;
 import com.nimbusds.jwt.JWTClaimsSet;
 import com.nimbusds.jwt.SignedJWT;
 import okhttp3.mockwebserver.MockResponse;
@@ -29,6 +48,9 @@ import org.junit.After;
 import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.Test;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.security.oauth2.core.OAuth2Error;
 import org.springframework.security.oauth2.core.OAuth2TokenValidator;
@@ -37,29 +59,19 @@ import org.springframework.security.oauth2.jose.TestKeys;
 import org.springframework.security.oauth2.jose.jws.MacAlgorithm;
 import org.springframework.security.oauth2.jose.jws.SignatureAlgorithm;
 import org.springframework.web.reactive.function.client.WebClient;
-import reactor.core.publisher.Flux;
-import reactor.core.publisher.Mono;
-
-import javax.crypto.SecretKey;
-import java.net.UnknownHostException;
-import java.security.KeyFactory;
-import java.security.NoSuchAlgorithmException;
-import java.security.interfaces.RSAPublicKey;
-import java.security.spec.EncodedKeySpec;
-import java.security.spec.InvalidKeySpecException;
-import java.security.spec.X509EncodedKeySpec;
-import java.text.ParseException;
-import java.time.Instant;
-import java.util.Base64;
-import java.util.Collections;
-import java.util.Date;
-import java.util.Map;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatCode;
 import static org.assertj.core.api.AssertionsForClassTypes.assertThatThrownBy;
-import static org.mockito.Mockito.*;
-import static org.springframework.security.oauth2.jwt.NimbusReactiveJwtDecoder.*;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+import static org.springframework.security.oauth2.jwt.NimbusReactiveJwtDecoder.withJwkSetUri;
+import static org.springframework.security.oauth2.jwt.NimbusReactiveJwtDecoder.withJwkSource;
+import static org.springframework.security.oauth2.jwt.NimbusReactiveJwtDecoder.withPublicKey;
+import static org.springframework.security.oauth2.jwt.NimbusReactiveJwtDecoder.withSecretKey;
 
 /**
  * @author Rob Winch
@@ -363,6 +375,46 @@ public class NimbusReactiveJwtDecoderTests {
 				.isInstanceOf(JwtException.class);
 	}
 
+	@Test
+	public void jwsKeySelectorWhenNoAlgorithmThenReturnsRS256Selector() {
+		JWKSource<JWKSecurityContext> jwkSource = mock(JWKSource.class);
+		JWSKeySelector<JWKSecurityContext> jwsKeySelector =
+				withJwkSetUri(this.jwkSetUri).jwsKeySelector(jwkSource);
+		assertThat(jwsKeySelector instanceof JWSVerificationKeySelector);
+		JWSVerificationKeySelector<JWKSecurityContext> jwsVerificationKeySelector =
+				(JWSVerificationKeySelector<JWKSecurityContext>) jwsKeySelector;
+		assertThat(jwsVerificationKeySelector.getExpectedJWSAlgorithm())
+				.isEqualTo(JWSAlgorithm.RS256);
+	}
+
+	@Test
+	public void jwsKeySelectorWhenOneAlgorithmThenReturnsSingleSelector() {
+		JWKSource<JWKSecurityContext> jwkSource = mock(JWKSource.class);
+		JWSKeySelector<JWKSecurityContext> jwsKeySelector =
+				withJwkSetUri(this.jwkSetUri).jwsAlgorithm(SignatureAlgorithm.RS512)
+						.jwsKeySelector(jwkSource);
+		assertThat(jwsKeySelector instanceof JWSVerificationKeySelector);
+		JWSVerificationKeySelector<JWKSecurityContext> jwsVerificationKeySelector =
+				(JWSVerificationKeySelector<JWKSecurityContext>) jwsKeySelector;
+		assertThat(jwsVerificationKeySelector.getExpectedJWSAlgorithm())
+				.isEqualTo(JWSAlgorithm.RS512);
+	}
+
+	@Test
+	public void jwsKeySelectorWhenMultipleAlgorithmThenReturnsCompositeSelector() {
+		JWKSource<JWKSecurityContext> jwkSource = mock(JWKSource.class);
+		JWSKeySelector<JWKSecurityContext> jwsKeySelector =
+				withJwkSetUri(this.jwkSetUri)
+						.jwsAlgorithm(SignatureAlgorithm.RS256)
+						.jwsAlgorithm(SignatureAlgorithm.RS512)
+						.jwsKeySelector(jwkSource);
+		assertThat(jwsKeySelector instanceof JWSAlgorithmMapJWSKeySelector);
+		JWSAlgorithmMapJWSKeySelector<?> jwsAlgorithmMapKeySelector =
+				(JWSAlgorithmMapJWSKeySelector<?>) jwsKeySelector;
+		assertThat(jwsAlgorithmMapKeySelector.getExpectedJWSAlgorithms())
+				.containsExactlyInAnyOrder(JWSAlgorithm.RS256, JWSAlgorithm.RS512);
+	}
+
 	private SignedJWT signedJwt(SecretKey secretKey, MacAlgorithm jwsAlgorithm, JWTClaimsSet claimsSet) throws Exception {
 		SignedJWT signedJWT = new SignedJWT(new JWSHeader(JWSAlgorithm.parse(jwsAlgorithm.getName())), claimsSet);
 		JWSSigner signer = new MACSigner(secretKey);