com.zotoh.core.crypto.JavaOfuscator.java Source code

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Here is the source code for com.zotoh.core.crypto.JavaOfuscator.java

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/*??
 * COPYRIGHT (C) 2008-2009 CHERIMOIA LLC. ALL RIGHTS RESERVED.
 *
 * THIS IS FREE SOFTWARE; YOU CAN REDISTRIBUTE IT AND/OR
 * MODIFY IT UNDER THE TERMS OF THE APACHE LICENSE, 
 * VERSION 2.0 (THE "LICENSE").
 *
 * THIS LIBRARY 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 LICENSE FOR THE SPECIFIC LANGUAGE GOVERNING PERMISSIONS 
 * AND LIMITATIONS UNDER THE LICENSE.
 *
 * You should have received a copy of the Apache License
 * along with this distribution; if not, you may obtain a copy of the 
 * License at 
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 ??*/

package com.zotoh.core.crypto;

import static com.zotoh.core.util.CoreUte.asBytes;
import static com.zotoh.core.util.CoreUte.asString;
import static com.zotoh.core.util.StrUte.isEmpty;

import javax.crypto.Cipher;

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

import com.zotoh.core.io.ByteOStream;

import javax.crypto.spec.SecretKeySpec;

/**
 * Obfuscation using SUN-java.
 *  
 * @author kenl
 *
 */
public final class JavaOfuscator extends BaseOfuscator {

    /* (non-Javadoc)
     * @see com.zotoh.core.crypto.BaseOfuscator#unobfuscate(java.lang.String)
     */
    public String unobfuscate(String encoded) throws Exception {
        return decrypt(encoded);
    }

    /* (non-Javadoc)
     * @see com.zotoh.core.crypto.BaseOfuscator#obfuscate(java.lang.String)
     */
    public String obfuscate(String clearText) throws Exception {
        return encrypt(clearText);
    }

    /**
     * 
     */
    public JavaOfuscator() {
    }

    private String encrypt(String clearText) throws Exception {
        if (isEmpty(clearText)) {
            return clearText;
        }
        Cipher c = getCipher(Cipher.ENCRYPT_MODE);
        ByteOStream baos = new ByteOStream();
        byte[] p = asBytes(clearText);
        byte[] out = new byte[Math.max(4096, c.getOutputSize(p.length))];
        int n = c.update(p, 0, p.length, out, 0);
        if (n > 0) {
            baos.write(out, 0, n);
        }
        n = c.doFinal(out, 0);
        if (n > 0) {
            baos.write(out, 0, n);
        }

        return Base64.encodeBase64URLSafeString(baos.asBytes());
    }

    private String decrypt(String encoded) throws Exception {
        if (isEmpty(encoded)) {
            return encoded;
        }
        Cipher c = getCipher(Cipher.DECRYPT_MODE);
        ByteOStream baos = new ByteOStream();
        byte[] p = Base64.decodeBase64(encoded);
        byte[] out = new byte[Math.max(4096, c.getOutputSize(p.length))];
        int n = c.update(p, 0, p.length, out, 0);
        if (n > 0) {
            baos.write(out, 0, n);
        }
        n = c.doFinal(out, 0);
        if (n > 0) {
            baos.write(out, 0, n);
        }

        return asString(baos.asBytes());
    }

    private Cipher getCipher(int mode) throws Exception {
        SecretKeySpec key = new SecretKeySpec(getKey(), getAlgo());
        Cipher c = Cipher.getInstance(getAlgo());
        c.init(mode, key);
        return c;
    }

}