io.amient.affinity.core.util.TimeCryptoProofSHA256 Maven / Gradle / Ivy

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/*
 * Copyright 2016 Michal Harish, [email protected]
 *
 * Licensed to 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 io.amient.affinity.core.util;

import javax.xml.bind.DatatypeConverter;
import java.nio.ByteBuffer;
import java.security.MessageDigest;
import java.time.ZoneOffset;
import java.time.ZonedDateTime;

public class TimeCryptoProofSHA256 extends TimeCryptoProof {

    /**
     * Construct a Thread-Safe instance of Crypto with a given salt
     *
     * @param salt byte array to be used as salt for encoding and decoding all inputs
     */
    public TimeCryptoProofSHA256(byte[] salt) {
        super(salt);
    }

    /**
     * Construct a Thread-Safe instance of Crypto with a given salt
     *
     * @param hexSalt hexadecimal representation of the salt to be used for encoding and decoding all inputs
     */
    public TimeCryptoProofSHA256(String hexSalt) {
        super(hexSalt);
    }

    @Override
    protected byte[] encode(byte[] input) throws Exception {
        MessageDigest digest = MessageDigest.getInstance("SHA-256");
        return digest.digest(input);
    }

    /**
     * Example standalone encode function for AES-256 salted crypto function
     *
     * @param arg     input string to encode
     * @param hexSalt hexadecimal representation of the salt
     * @param shift   timeshift in minutes with respect to current UTC time
     * @return result time-based encode
     * @throws Exception if anything goes wrong
     */
    public String timeBasedHash(String arg, String hexSalt, int shift) throws Exception {
        byte[] salt = DatatypeConverter.parseHexBinary(hexSalt);
        long utcWholeMinute = ZonedDateTime.now(ZoneOffset.UTC)
                .withNano(0).withSecond(0).toEpochSecond() + shift * 60;
        byte[] argBytes = arg.getBytes();
        ByteBuffer in = ByteBuffer.allocate(salt.length + 8 + argBytes.length);
        in.put(salt);
        in.putLong(utcWholeMinute);
        in.put(argBytes);
        in.flip();
        MessageDigest digest = MessageDigest.getInstance("SHA-256");
        byte[] hash = digest.digest(in.array());
        String hexHash = DatatypeConverter.printHexBinary(hash);
        return hexHash;
    }

    /*
     * Example PHP equivalent of the timebased hash:
     *