it.scoppelletti.programmerpower.security.spi.PBEParameterSpecFactory.java Source code

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Here is the source code for it.scoppelletti.programmerpower.security.spi.PBEParameterSpecFactory.java

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/*
 * Copyright (C) 2010 Dario Scoppelletti, <http://www.scoppelletti.it/>.
 * 
 * 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 it.scoppelletti.programmerpower.security.spi;

import java.util.*;
import java.security.spec.*;
import javax.crypto.spec.*;
import org.apache.commons.codec.*;
import org.apache.commons.codec.binary.*;
import it.scoppelletti.programmerpower.*;
import it.scoppelletti.programmerpower.security.*;
import it.scoppelletti.programmerpower.types.*;

/**
 * Classe di factory dell&rsquo;insieme dei parametri per un algoritmo
 * <ACRONYM TITLE="Password Based Encryption">PBE</ACRONYM>.
 *  
 *
 * <P><TABLE WIDTH="100%" BORDER="1" CELLPADDING="5">
 * <THEAD>
 * <TR>
 *     <TH>Propriet&agrave;</TH>
 *     <TH>Descrizione</TH>     
 * </TR>
 * </THEAD>
 * <TBODY>     
 * <TR>
 *      <TD>{@code salt}</TD>
 *      <TD>Sequenza di byte {@code salt} in formato esadecimale.</TD>
 * </TR>
 * <TR>
 *      <TD>{@code iterations}</TD>
 *      <TD>Numero di iterazioni.</TD>
 * </TR>
 * </TBODY>
 * </TABLE></P>
 * 
 * @see   it.scoppelletti.programmerpower.security.CryptoUtils#getCipher
 * @see   <A HREF="{@docRoot}/it/scoppelletti/programmerpower/security/CryptoUtils.html#idAlg">Algoritmi
 *        di crittografia</A> 
 * @see   <A HREF="http://www.rsa.com/rsalabs" TARGET="_blank">PKCS &#35;5:
 *        Password-Based Cryptography Standard</A>          
 * @see   <A HREF="http://www.ietf.org/rfc/rfc2898.txt" TARGET="_blank">RFC
 *        2898 / PKCS #5: Password-Based Cryptography Specification</A>        
 * @since 1.0.0
 */
public final class PBEParameterSpecFactory implements AlgorithmParameterSpecFactory {

    /**
     * Nome della propriet&agrave; sulla quale deve essere impostata la
     * sequenza di byte {@code salt}. Il valore della costante &egrave;
     * <CODE>{@value}</CODE>.  
     */
    public static final String PROP_SALT = "salt";

    /**
     * Nome della propriet&agrave; sulla quale deve essere impostato il numero
     * di iterazioni. Il valore della costante &egrave; <CODE>{@value}</CODE>.  
     */
    public static final String PROP_ITERATIONCOUNT = "iterations";

    /**
     * Costruttore.
     */
    public PBEParameterSpecFactory() {
    }

    public AlgorithmParameterSpec newInstance(Properties props, String prefix) {
        int count;
        String name, value;
        byte[] salt;
        PBEParameterSpec param;

        name = Strings.concat(prefix, PBEParameterSpecFactory.PROP_SALT);
        value = props.getProperty(name);
        if (Strings.isNullOrEmpty(value)) {
            throw new ArgumentNullException(name);
        }

        try {
            salt = Hex.decodeHex(value.toCharArray());
        } catch (DecoderException ex) {
            throw SecurityUtils.toSecurityException(ex);
        }

        name = Strings.concat(prefix, PBEParameterSpecFactory.PROP_ITERATIONCOUNT);
        value = props.getProperty(name);
        if (Strings.isNullOrEmpty(value)) {
            throw new ArgumentNullException(name);
        }
        count = Integer.parseInt(value);

        param = new PBEParameterSpec(salt, count);

        return param;
    }
}