package encryptandunencrypt;

import java.io.*;
import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;

public class UnEncrypt {
    private String fenge = java.io.File.separator;
    public void UnEncrypt() throws Exception {
        //僼傽僀儖傪僥僗僩偟偰懚嵼偡傞偐偳偆偐丅
        String encryptedFileExist = "bo" + fenge + "encrypt" + fenge +
                                    "bnavie_exp_enc.xml";
        File fileName = new File(encryptedFileExist);
        boolean result = fileName.exists();
        if (!result) {
            return;
        } else {
//岞奐尞傪宍惉偡傞
            byte[] keykb = {
                           28, -1, 64, 64, 71, 106, 1, 72, -31, 47, -108, -75,
                           -110,
                           78, 33, 105};
            SecretKeySpec secretKeySpec = new SecretKeySpec(keykb, "BlowFish");

            //the file name of unencrypt丅
            String encrypt = "bo" + fenge + "unencrypt" + fenge +
                             "bnavie_exp.xml";

            try {
                //埫崋壔偺曽幃傪憂寶偟偰弶婜壔偡傞丅
                Cipher cipher = null;
                cipher = Cipher.getInstance("BlowFish");
                cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);

                //憂寶偺埫崋壔偡傞偺偼晧偗偰帪悽偵崌偆丅
                FileInputStream fileInputStream = null;
                fileInputStream = new FileInputStream(encryptedFileExist);

                //CipherInputStream懳徾傪憂寶偡傞丅
                CipherInputStream cipherInputStream = new CipherInputStream(
                        fileInputStream, cipher);

                //強偼枾側(cè)寢壥傪棟夝偡傞丅
                FileOutputStream fileOutputStream = null;
                fileOutputStream = new FileOutputStream(encrypt);

                //晧偗傞偙偲傪摼偰帪悽偵崌偆丅
                int b = 0;
                while ((b = cipherInputStream.read()) != -1) {
                    fileOutputStream.write(b);
                }

                //偡傋偰偺桝弌擖傪暵嵔偟偰棳傟傞丅
                fileInputStream.close();
                cipherInputStream.close();
                fileOutputStream.close();

                //嶍彍偟偰埫崋壔偟偨屻偺僥儞億儔儕僼傽僀儖丅
                String xmlField = "bo" + fenge + "unencrypt" + fenge +
                                  "bnavie_exp_enc.xml";
                File xmlFile = new File(xmlField);
                xmlFile.delete();
            } catch (Exception ex) {
                ex.printStackTrace();
                throw ex;
            }
        }

    }
}