org.mitre.jwt.signer.AbstractJwtSigner.java Source code

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Here is the source code for org.mitre.jwt.signer.AbstractJwtSigner.java

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/*******************************************************************************
 * Copyright 2012 The MITRE Corporation
 * 
 * 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.mitre.jwt.signer;

import java.security.NoSuchAlgorithmException;
import java.util.List;

import org.mitre.jwt.model.Jwt;
import com.google.common.base.Splitter;
import com.google.common.base.Strings;
import com.google.common.collect.Lists;

public abstract class AbstractJwtSigner implements JwtSigner {

    private JwsAlgorithm algorithm;

    public AbstractJwtSigner(JwsAlgorithm algorithm) {
        this.algorithm = algorithm;
    }

    /**
      * @return the algorithm
      */
    public JwsAlgorithm getAlgorithm() {
        return algorithm;
    }

    /**
      * @param algorithm the algorithm to set
      */
    public void setAlgorithm(JwsAlgorithm algorithm) {
        this.algorithm = algorithm;
    }

    /**
     * Ensures that the 'alg' of the given JWT matches the {@link #algorithm} of this signer
     * and signs the jwt.
     * 
     * @param jwt the jwt to sign
     * @return the signed jwt
     * @throws NoSuchAlgorithmException 
     */
    @Override
    public Jwt sign(Jwt jwt) throws NoSuchAlgorithmException {

        //TODO: need a seperate check for Jwe. As is, it will change the alg param to be the enc param
        /*if (!Objects.equal(algorithm, jwt.getHeader().getAlgorithm())) {
           // algorithm type doesn't match
           // TODO: should this be an error or should we just fix it in the incoming jwt?
           // for now, we fix the Jwt
           jwt.getHeader().setAlgorithm(algorithm);         
        }*/

        String sig = generateSignature(jwt.getSignatureBase());

        jwt.setSignature(sig);

        return jwt;
    }

    /* (non-Javadoc)
      * @see org.mitre.jwt.JwtSigner#verify(java.lang.String)
      */
    @Override
    public boolean verify(String jwtString) throws NoSuchAlgorithmException {
        // split on the dots
        List<String> parts = Lists.newArrayList(Splitter.on(".").split(jwtString));

        if (parts.size() != 3) {
            throw new IllegalArgumentException("Invalid JWT format.");
        }

        String h64 = parts.get(0);
        String c64 = parts.get(1);
        String s64 = parts.get(2);

        String expectedSignature = generateSignature(h64 + "." + c64);

        return Strings.nullToEmpty(s64).equals(Strings.nullToEmpty(expectedSignature));

    }

    protected abstract String generateSignature(String signatureBase) throws NoSuchAlgorithmException;
}