net.sf.keystore_explorer.crypto.digest.DigestUtil.java Source code

Introduction

Here is the source code for net.sf.keystore_explorer.crypto.digest.DigestUtil.java

Source

/*
 * Copyright 2004 - 2013 Wayne Grant
 *           2013 - 2016 Kai Kramer
 *
 * This file is part of KeyStore Explorer.
 *
 * KeyStore Explorer 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.
 *
 * KeyStore Explorer 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 KeyStore Explorer.  If not, see <http://www.gnu.org/licenses/>.
 */
package net.sf.keystore_explorer.crypto.digest;

import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.text.MessageFormat;
import java.util.ResourceBundle;

import org.apache.commons.io.IOUtils;

import net.sf.keystore_explorer.crypto.CryptoException;

/**
 * Provides utility methods for the creation of message digests.
 *
 */
public final class DigestUtil {
    private static ResourceBundle res = ResourceBundle
            .getBundle("net/sf/keystore_explorer/crypto/digest/resources");

    private DigestUtil() {
    }

    /**
     * Get a digest of the input stream.
     *
     * @param istream
     *            Input stream to digest
     * @param digestType
     *            The message digest algorithm
     * @return The message digest
     * @throws CryptoException
     *             If message digester could not be created
     */
    public static byte[] getMessageDigest(InputStream istream, DigestType digestType) throws CryptoException {
        MessageDigest messageDigester = getMessageDigester(digestType);

        try {
            byte[] buffer = new byte[2048];
            int read = 0;

            while ((read = istream.read(buffer)) != -1) {
                messageDigester.update(buffer, 0, read);
            }

            byte[] messageDigest = messageDigester.digest();

            return messageDigest;
        } catch (IOException ex) {
            throw new CryptoException(res.getString("NoCreateDigest.exception.message"), ex);
        } finally {
            IOUtils.closeQuietly(istream);
        }
    }

    /**
     * Get a digest of the supplied message.
     *
     * @param message
     *            The message to digest
     * @param digestType
     *            The message digest algorithm
     * @return The message digest
     * @throws CryptoException
     *             If message digester could not be created
     */
    public static byte[] getMessageDigest(byte[] message, DigestType digestType) throws CryptoException {
        MessageDigest messageDigester = getMessageDigester(digestType);

        return messageDigester.digest(message);
    }

    /**
     * Get the digest of a message as a formatted String. Returned in base-16
     * with ':' separators every two characters padded with a leading 0 if
     * necessary to make for an even number of hex characters.
     *
     * @param message
     *            The message to digest
     * @param digestType
     *            The message digest algorithm
     * @return The message digest
     * @throws CryptoException
     *             If message digester could not be created
     */
    public static String getFriendlyMessageDigest(byte[] message, DigestType digestType) throws CryptoException {
        byte[] messageDigest = getMessageDigest(message, digestType);

        StringBuffer strBuff = new StringBuffer(new BigInteger(1, messageDigest).toString(16).toUpperCase());

        if ((strBuff.length() % 2) == 1) {
            strBuff.insert(0, '0');
        }

        if (strBuff.length() > 2) {
            for (int i = 2; i < strBuff.length(); i += 3) {
                strBuff.insert(i, ':');
            }
        }

        return strBuff.toString();
    }

    /**
     * Create message digester of supplied type.
     *
     * @param digestType
     *            Digest type
     * @return Message digester
     * @throws CryptoException
     *             If message digester could not be created
     */
    public static MessageDigest getMessageDigester(DigestType digestType) throws CryptoException {
        try {
            return MessageDigest.getInstance(digestType.jce());
        } catch (NoSuchAlgorithmException ex) {
            throw new CryptoException(
                    MessageFormat.format(res.getString("NoCreateDigester.exception.message"), digestType.jce()),
                    ex);
        }
    }
}