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 * Open Behavioral Health Information Technology Architecture (OBHITA.org)
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 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
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package gov.samhsa.acs.common.util;

import java.io.File;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;

import org.apache.xml.security.utils.JavaUtils;
import org.w3c.dom.Document;

/**
 * The Class DecryptTool.
 */
public class DecryptTool {
	static {
        org.apache.xml.security.Init.init();
    }

    /**
     * Load encryption document.
     *
     * @param fileName the file name
     * @return the document
     * @throws Exception the exception
     */
    private static Document loadEncryptionDocument(String fileName) throws Exception {       
        File encryptionFile = new File(fileName);
        javax.xml.parsers.DocumentBuilderFactory dbf =
            javax.xml.parsers.DocumentBuilderFactory.newInstance();
        dbf.setNamespaceAware(true);
        javax.xml.parsers.DocumentBuilder db = dbf.newDocumentBuilder();
        Document document = db.parse(encryptionFile);
        
        return document;
    }

    /**
     * Load key encryption key.
     *
     * @param fileName the file name
     * @return the secret key
     * @throws Exception the exception
     */
    private static SecretKey loadKeyEncryptionKey(String fileName) throws Exception {        
        String jceAlgorithmName = "DESede";

        File kekFile = new File(fileName);

        DESedeKeySpec keySpec =
            new DESedeKeySpec(JavaUtils.getBytesFromFile(fileName));
        SecretKeyFactory skf =
             SecretKeyFactory.getInstance(jceAlgorithmName);
        SecretKey key = skf.generateSecret(keySpec);
        return key;
    }
}