desapp.java

这是我写的一个关于JAVA SOCKET的程序

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

/**
 * use java security des class to 
 * implement the encryption and 
 * dencryption
 */

public class DesApp {
	Key key = null;
	KeyGenerator generator = null;
	
	public DesApp() {
		try {
			generator = KeyGenerator.getInstance("DES");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}
	}
	
	/**
	 * generate KEY
	 * 
	 * @param strKey
	 */
	public void getKey(String strKey) {
		try {
			generator.init(new SecureRandom(strKey.getBytes()));
			this.key = generator.generateKey();
			generator = null;
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/**
	 * encrypt String
	 * 
	 * @param strMing
	 * @return
	 */
	public String getEncString(String strMing) {
		byte[] byteMi = null;
		byte[] byteMing = null;
		String strMi = "";
		BASE64Encoder base64en = new BASE64Encoder();
		try {
			byteMing = strMing.getBytes("UTF8");
			byteMi = this.getEncCode(byteMing);
			strMi = base64en.encode(byteMi);
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			base64en = null;
			byteMing = null;
			byteMi = null;
		}
		return strMi;
	}

	/**
	 * dencrypt String
	 * 
	 * @param strMi
	 * @return
	 */
	public String getDesString(String strMi) {
		BASE64Decoder base64De = new BASE64Decoder();
		byte[] byteMing = null;
		byte[] byteMi = null;
		String strMing = "";
		try {
			byteMi = base64De.decodeBuffer(strMi);
			byteMing = this.getDesCode(byteMi);
			strMing = new String(byteMing, "UTF8");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			base64De = null;
			byteMing = null;
			byteMi = null;
		}
		return strMing;
	}

	/**
	 * encrypt byte[]
	 * 
	 * @param byteS
	 * @return
	 */
	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;
	}

	/**
	 * dencrypt byte[] cipher, output byte[] plain text
	 * 
	 * @param byteD
	 * @return
	 */
	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;

	}
	
	/*
	public static void main(String[] args){ 
		System.out.println("des demo");
		DesApp des=new DesApp();
		des.getKey("MYKEY11");
		System.out.println("key=MYKEY11");
		String strEnc = des.getEncString("QIU_SHI");
		System.out.println("密文="+strEnc);

		String strDes = des.getDesString(strEnc);
		System.out.println("明文="+strDes);

		} 
		*/
	
}