diff --git a/oauth2/oauth2-jose/src/main/java/org/springframework/security/oauth2/jwt/NimbusJwkReactiveJwtDecoder.java b/oauth2/oauth2-jose/src/main/java/org/springframework/security/oauth2/jwt/NimbusJwkReactiveJwtDecoder.java
new file mode 100644
index 0000000000..1f68843ede
--- /dev/null
+++ b/oauth2/oauth2-jose/src/main/java/org/springframework/security/oauth2/jwt/NimbusJwkReactiveJwtDecoder.java
@@ -0,0 +1,157 @@
+/*
+ * Copyright 2002-2018 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
+ *
+ * http://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 com.nimbusds.jose.JOSEException;
+import com.nimbusds.jose.JWSAlgorithm;
+import com.nimbusds.jose.jwk.JWK;
+import com.nimbusds.jose.jwk.JWKSelector;
+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.jwt.JWT;
+import com.nimbusds.jwt.JWTClaimsSet;
+import com.nimbusds.jwt.JWTParser;
+import com.nimbusds.jwt.SignedJWT;
+import com.nimbusds.jwt.proc.DefaultJWTProcessor;
+import com.nimbusds.jwt.proc.JWTProcessor;
+import org.springframework.security.oauth2.jose.jws.JwsAlgorithms;
+import org.springframework.util.Assert;
+import reactor.core.publisher.Mono;
+
+import java.time.Instant;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * An implementation of a {@link JwtDecoder} that "decodes" a
+ * JSON Web Token (JWT) and additionally verifies it's digital signature if the JWT is a
+ * JSON Web Signature (JWS). The public key used for verification is obtained from the
+ * JSON Web Key (JWK) Set {@code URL} supplied via the constructor.
+ *
+ *
+ * NOTE: This implementation uses the Nimbus JOSE + JWT SDK internally.
+ *
+ * @author Rob Winch
+ * @since 5.1
+ * @see JwtDecoder
+ * @see JSON Web Token (JWT)
+ * @see JSON Web Signature (JWS)
+ * @see JSON Web Key (JWK)
+ * @see Nimbus JOSE + JWT SDK
+ */
+public final class NimbusJwkReactiveJwtDecoder implements ReactiveJwtDecoder {
+ private final JWTProcessor jwtProcessor;
+
+ private final ReactiveRemoteJWKSource reactiveJwkSource;
+
+ private final JWKSelectorFactory jwkSelectorFactory;
+
+ /**
+ * Constructs a {@code NimbusJwtDecoderJwkSupport} using the provided parameters.
+ *
+ * @param jwkSetUrl the JSON Web Key (JWK) Set {@code URL}
+ */
+ public NimbusJwkReactiveJwtDecoder(String jwkSetUrl) {
+ this(jwkSetUrl, JwsAlgorithms.RS256);
+ }
+
+ /**
+ * Constructs a {@code NimbusJwtDecoderJwkSupport} using the provided parameters.
+ *
+ * @param jwkSetUrl the JSON Web Key (JWK) Set {@code URL}
+ * @param jwsAlgorithm the JSON Web Algorithm (JWA) used for verifying the digital signatures
+ */
+ public NimbusJwkReactiveJwtDecoder(String jwkSetUrl, String jwsAlgorithm) {
+ Assert.hasText(jwkSetUrl, "jwkSetUrl cannot be empty");
+ Assert.hasText(jwsAlgorithm, "jwsAlgorithm cannot be empty");
+
+ JWSAlgorithm algorithm = JWSAlgorithm.parse(jwsAlgorithm);
+ JWKSource jwkSource = new JWKContextJWKSource();
+ JWSKeySelector jwsKeySelector =
+ new JWSVerificationKeySelector<>(algorithm, jwkSource);
+
+ DefaultJWTProcessor jwtProcessor = new DefaultJWTProcessor<>();
+ jwtProcessor.setJWSKeySelector(jwsKeySelector);
+ this.jwtProcessor = jwtProcessor;
+
+ this.reactiveJwkSource = new ReactiveRemoteJWKSource(jwkSetUrl);
+
+ this.jwkSelectorFactory = new JWKSelectorFactory(algorithm);
+
+ }
+
+ @Override
+ public Mono decode(String token) throws JwtException {
+ JWT jwt = parse(token);
+ if (jwt instanceof SignedJWT) {
+ return this.decode((SignedJWT) jwt);
+ }
+ return Mono.empty();
+ }
+
+ private JWT parse(String token) {
+ try {
+ return JWTParser.parse(token);
+ } catch (Exception ex) {
+ throw new JwtException("An error occurred while attempting to decode the Jwt: " + ex.getMessage(), ex);
+ }
+ }
+
+ private Mono decode(SignedJWT parsedToken) {
+ try {
+ JWKSelector selector = this.jwkSelectorFactory
+ .createSelector(parsedToken.getHeader());
+ return this.reactiveJwkSource.get(selector)
+ .map(jwkList -> createJwkSet(parsedToken, jwkList))
+ .map(set -> createJwt(parsedToken, set));
+ } catch (Exception ex) {
+ throw new JwtException("An error occurred while attempting to decode the Jwt: " + ex.getMessage(), ex);
+ }
+ }
+
+ private JWTClaimsSet createJwkSet(JWT parsedToken, List jwkList) {
+ try {
+ return this.jwtProcessor.process(parsedToken, new JWKContext(jwkList));
+ }
+ catch (BadJOSEException e) {
+ throw new RuntimeException(e);
+ }
+ catch (JOSEException e) {
+ throw new RuntimeException(e);
+ }
+ }
+
+ private Jwt createJwt(JWT parsedJwt, JWTClaimsSet jwtClaimsSet) {
+ Instant expiresAt = null;
+ if (jwtClaimsSet.getExpirationTime() != null) {
+ expiresAt = jwtClaimsSet.getExpirationTime().toInstant();
+ }
+ Instant issuedAt = null;
+ if (jwtClaimsSet.getIssueTime() != null) {
+ issuedAt = jwtClaimsSet.getIssueTime().toInstant();
+ } else if (expiresAt != null) {
+ // Default to expiresAt - 1 second
+ issuedAt = Instant.from(expiresAt).minusSeconds(1);
+ }
+
+ Map headers = new LinkedHashMap<>(parsedJwt.getHeader().toJSONObject());
+
+ return new Jwt(parsedJwt.getParsedString(), issuedAt, expiresAt, headers, jwtClaimsSet.getClaims());
+ }
+}
diff --git a/oauth2/oauth2-jose/src/main/java/org/springframework/security/oauth2/jwt/ReactiveJwtDecoder.java b/oauth2/oauth2-jose/src/main/java/org/springframework/security/oauth2/jwt/ReactiveJwtDecoder.java
new file mode 100644
index 0000000000..8ecf5d3e63
--- /dev/null
+++ b/oauth2/oauth2-jose/src/main/java/org/springframework/security/oauth2/jwt/ReactiveJwtDecoder.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2002-2018 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
+ *
+ * http://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 reactor.core.publisher.Mono;
+
+/**
+ * Implementations of this interface are responsible for "decoding"
+ * a JSON Web Token (JWT) from it's compact claims representation format to a {@link Jwt}.
+ *
+ *
+ * JWTs may be represented using the JWS Compact Serialization format for a
+ * JSON Web Signature (JWS) structure or JWE Compact Serialization format for a
+ * JSON Web Encryption (JWE) structure. Therefore, implementors are responsible
+ * for verifying a JWS and/or decrypting a JWE.
+ *
+ * @author Rob Winch
+ * @since 5.1
+ * @see Jwt
+ * @see JSON Web Token (JWT)
+ * @see JSON Web Signature (JWS)
+ * @see JSON Web Encryption (JWE)
+ * @see JWS Compact Serialization
+ * @see JWE Compact Serialization
+ */
+public interface ReactiveJwtDecoder {
+
+ /**
+ * Decodes the JWT from it's compact claims representation format and returns a {@link Jwt}.
+ *
+ * @param token the JWT value
+ * @return a {@link Jwt}
+ * @throws JwtException if an error occurs while attempting to decode the JWT
+ */
+ Mono decode(String token) throws JwtException;
+
+}