001package com.nimbusds.jose.crypto;
002
003
004import java.nio.charset.Charset;
005import java.util.Set;
006
007import javax.crypto.SecretKey;
008
009import net.jcip.annotations.ThreadSafe;
010
011import com.nimbusds.jose.*;
012import com.nimbusds.jose.jwk.OctetSequenceKey;
013import com.nimbusds.jose.util.Base64URL;
014
015
016/**
017 * Message Authentication Code (MAC) verifier of 
018 * {@link com.nimbusds.jose.JWSObject JWS objects}. This class is thread-safe.
019 *
020 * <p>Supports the following algorithms:
021 *
022 * <ul>
023 *     <li>{@link com.nimbusds.jose.JWSAlgorithm#HS256}
024 *     <li>{@link com.nimbusds.jose.JWSAlgorithm#HS384}
025 *     <li>{@link com.nimbusds.jose.JWSAlgorithm#HS512}
026 * </ul>
027 * 
028 * @author Vladimir Dzhuvinov
029 * @version 2015-06-02
030 */
031@ThreadSafe
032public class MACVerifier extends MACProvider implements JWSVerifier, CriticalHeaderParamsAware {
033
034
035        /**
036         * The critical header policy.
037         */
038        private final CriticalHeaderParamsDeferral critPolicy = new CriticalHeaderParamsDeferral();
039
040
041        /**
042         * Creates a new Message Authentication (MAC) verifier.
043         *
044         * @param secret The secret. Must be at least 256 bits long and not
045         *               {@code null}.
046         *
047         * @throws JOSEException If the secret length is shorter than the
048         *                       minimum 256-bit requirement.
049         */
050        public MACVerifier(final byte[] secret)
051                throws JOSEException {
052
053                this(secret, null);
054        }
055
056
057        /**
058         * Creates a new Message Authentication (MAC) verifier.
059         *
060         * @param secretString The secret as a UTF-8 encoded string. Must be at
061         *                     least 256 bits long and not {@code null}.
062         *
063         * @throws JOSEException If the secret length is shorter than the
064         *                       minimum 256-bit requirement.
065         */
066        public MACVerifier(final String secretString)
067                throws JOSEException {
068
069                this(secretString.getBytes(Charset.forName("UTF-8")));
070        }
071
072
073        /**
074         * Creates a new Message Authentication (MAC) verifier.
075         *
076         * @param secretKey The secret key. Must be at least 256 bits long and
077         *                  not {@code null}.
078         *
079         * @throws JOSEException If the secret length is shorter than the
080         *                       minimum 256-bit requirement.
081         */
082        public MACVerifier(final SecretKey secretKey)
083                throws JOSEException {
084
085                this(secretKey.getEncoded());
086        }
087
088
089        /**
090         * Creates a new Message Authentication (MAC) verifier.
091         *
092         * @param jwk The secret as a JWK. Must be at least 256 bits long and
093         *            not {@code null}.
094         *
095         * @throws JOSEException If the secret length is shorter than the
096         *                       minimum 256-bit requirement.
097         */
098        public MACVerifier(final OctetSequenceKey jwk)
099                throws JOSEException {
100
101                this(jwk.toByteArray());
102        }
103
104
105        /**
106         * Creates a new Message Authentication (MAC) verifier.
107         *
108         * @param secret         The secret. Must be at least 256 bits long
109         *                       and not {@code null}.
110         * @param defCritHeaders The names of the critical header parameters
111         *                       that are deferred to the application for
112         *                       processing, empty set or {@code null} if none.
113         *
114         * @throws JOSEException If the secret length is shorter than the
115         *                       minimum 256-bit requirement.
116         */
117        public MACVerifier(final byte[] secret,
118                           final Set<String> defCritHeaders)
119                throws JOSEException {
120
121                super(secret, SUPPORTED_ALGORITHMS);
122
123                critPolicy.setDeferredCriticalHeaderParams(defCritHeaders);
124        }
125
126
127        @Override
128        public Set<String> getProcessedCriticalHeaderParams() {
129
130                return critPolicy.getProcessedCriticalHeaderParams();
131        }
132
133
134        @Override
135        public Set<String> getDeferredCriticalHeaderParams() {
136
137                return critPolicy.getProcessedCriticalHeaderParams();
138        }
139
140
141        @Override
142        public boolean verify(final JWSHeader header,
143                              final byte[] signedContent, 
144                              final Base64URL signature)
145                throws JOSEException {
146
147                if (! critPolicy.headerPasses(header)) {
148                        return false;
149                }
150
151                String jcaAlg = getJCAAlgorithmName(header.getAlgorithm());
152                byte[] expectedHMAC = HMAC.compute(jcaAlg, getSecret(), signedContent, getJCAContext().getProvider());
153                return ConstantTimeUtils.areEqual(expectedHMAC, signature.decode());
154        }
155}