com.streamsets.lib.security.util.DataSignature.java Source code

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Here is the source code for com.streamsets.lib.security.util.DataSignature.java

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/**
 * Copyright 2016 StreamSets Inc.
 *
 * Licensed under the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 com.streamsets.lib.security.util;

import org.apache.commons.codec.binary.Base64;

import java.security.GeneralSecurityException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Signature;
import java.security.spec.X509EncodedKeySpec;

public class DataSignature {

    public interface Signer {

        byte[] sign(byte[] data) throws GeneralSecurityException;

    }

    public interface Verifier {

        boolean verify(byte[] data, byte[] signature) throws GeneralSecurityException;

    }

    private static final DataSignature DATA_SIGNATURE = new DataSignature();

    public static DataSignature get() {
        return DATA_SIGNATURE;
    }

    private DataSignature() {
    }

    public KeyPair generateKeyPair() throws GeneralSecurityException {
        KeyPairGenerator keyGenerator = KeyPairGenerator.getInstance("DSA");
        SecureRandom rng = SecureRandom.getInstance("SHA1PRNG", "SUN");
        rng.setSeed(System.currentTimeMillis());
        keyGenerator.initialize(1024, rng);
        return keyGenerator.generateKeyPair();
    }

    public String encodePublicKey(PublicKey publicKey) {
        return Base64.encodeBase64String(publicKey.getEncoded());
    }

    public PublicKey decodePublicKey(String encodedPublicKey) throws GeneralSecurityException {
        byte[] bytes = Base64.decodeBase64(encodedPublicKey);
        X509EncodedKeySpec pubKeySpec = new X509EncodedKeySpec(bytes);
        KeyFactory keyFactory = KeyFactory.getInstance("DSA", "SUN");
        return keyFactory.generatePublic(pubKeySpec);
    }

    public Signer getSigner(final PrivateKey privateKey) {
        return new Signer() {
            @Override
            public byte[] sign(byte[] data) throws GeneralSecurityException {
                Signature signer = Signature.getInstance("SHA1withDSA");
                signer.initSign(privateKey);
                signer.update(data);
                return signer.sign();
            }
        };
    }

    public Verifier getVerifier(final PublicKey publicKey) {
        return new Verifier() {
            @Override
            public boolean verify(byte[] data, byte[] signature) throws GeneralSecurityException {
                Signature signer = Signature.getInstance("SHA1withDSA");
                signer.initVerify(publicKey);
                signer.update(data);
                return signer.verify(signature);
            }
        };
    }

}