package com.xwtec.Interpreter.EncryptMtic;

import java.security.Key;
import javax.crypto.KeyGenerator;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import sun.misc.BASE64Encoder;
import sun.misc.BASE64Decoder;

/**
 *   使用DES加密與解密,可對byte[],String類型進行加密與解密
 *   密文可使用String,byte[]存儲.
 *   方法:
 *   void getKey(String   strKey)從strKey的字條生成一個Key
 *   String getEncString(String strMing)對strMing進行加密,返回String密文
 *   String getDesString(String strMi)對strMin進行解密,返回String明文
 *   byte[] getEncCode(byte[] byteS)byte[]型的加密
 *   byte[] getDesCode(byte[] byteD)byte[]型的解密
 */
public class Encrypt {
    private Key key;
    private byte[] byteMi = null;
    private byte[] byteMing = null;
    private String strMi = "";
    private String strM = "";
    //  根據參數生成KEY
    public void setKey(String strKey) {
        try {
            KeyGenerator _generator = KeyGenerator.getInstance("DES");
            _generator.init(new SecureRandom(strKey.getBytes()));
            this.key = _generator.generateKey();
            _generator = null;
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    //  加密String明文輸入,String密文輸出
    public void setEncString(String strMing) {
        BASE64Encoder base64en = new BASE64Encoder();
        try {
            this.byteMing = strMing.getBytes("UTF8");
            this.byteMi = this.getEncCode(this.byteMing);
            this.strMi = base64en.encode(this.byteMi);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {

            this.byteMing = null;
            this.byteMi = null;
        }
    }

    //加密以byte[]明文輸入,byte[]密文輸出
    private byte[] getEncCode(byte[] byteS) {
        byte[] byteFina = null;
        Cipher cipher;
        try {
            cipher = Cipher.getInstance("DES");
            cipher.init(Cipher.ENCRYPT_MODE, key);
            byteFina = cipher.doFinal(byteS);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            cipher = null;
        }

        return byteFina;
    }

// 解密:以String密文輸入,String明文輸出
    public void setDesString(String strMi) {
        BASE64Decoder base64De = new BASE64Decoder();
        try {
            this.byteMi = base64De.decodeBuffer(strMi);
            this.byteMing = this.getDesCode(byteMi);
            this.strM = new String(byteMing, "UTF8");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            base64De = null;
            byteMing = null;
            byteMi = null;
        }

    }

    // 解密以byte[]密文輸入,以byte[]明文輸出
    private byte[] getDesCode(byte[] byteD) {
        Cipher cipher;
        byte[] byteFina = null;
        try {
            cipher = Cipher.getInstance("DES");
            cipher.init(Cipher.DECRYPT_MODE, key);
            byteFina = cipher.doFinal(byteD);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            cipher = null;
        }
        return byteFina;
    }

    //返回加密后的密文strMi
    public String getStrMi() {
        return strMi;
    }

    //返回解密后的明文
    public String getStrM() {
        return strM;
    }
}