org.sperle.keepass.crypto.bc.SHA256Hash.java Source code

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Here is the source code for org.sperle.keepass.crypto.bc.SHA256Hash.java

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/*
Copyright (c) 2009-2010 Christoph Sperle <keepassmobile@gmail.com>
    
This file is part of KeePassMobile.
    
KeePassMobile is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
    
KeePassMobile is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
    
You should have received a copy of the GNU General Public License
along with KeePassMobile.  If not, see <http://www.gnu.org/licenses/>.
    
*/

package org.sperle.keepass.crypto.bc;

import org.bouncycastle.crypto.digests.SHA256Digest;
import org.sperle.keepass.crypto.Hash;
import org.sperle.keepass.monitor.ProgressMonitor;

/**
 * The SHA-256 hash using bouncy castle.
 */
public final class SHA256Hash implements Hash {
    public static final String NAME = "SHA256";
    private static final int DWORD_LENGTH = 4;

    public String getName() {
        return NAME;
    }

    public byte[] getHash(byte[][] messages, ProgressMonitor pm) {
        SHA256Digest md = new SHA256Digest();
        if (pm != null)
            pm.nextStep(sumLength(messages) / DWORD_LENGTH, "pm_hash");
        for (int i = 0; i < messages.length; i++) {
            md.update(messages[i], 0, messages[i].length, pm);
            if (pm != null && pm.isCanceled())
                return null;
        }
        byte[] hash = new byte[md.getDigestSize()];
        md.doFinal(hash, 0);
        return hash;
    }

    private int sumLength(byte[][] messages) {
        int sum = 0;
        for (int i = 0; i < messages.length; i++) {
            sum += messages[i].length;
        }
        return sum;
    }
}