DES加密、解密

最新推荐文章于 2021-02-12 16:03:47 发布

最新推荐文章于 2021-02-12 16:03:47 发布 · 153 阅读

文章标签：

#Security #Java #log4j #SUN #Apache

本文介绍了一个使用Java实现的DES加密和解密工具类。该工具类通过提供加密和解密方法，帮助用户对字符串进行DES算法的安全处理。文章展示了如何初始化加密密钥、设置加密算法，并提供了具体的加密和解密过程。

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import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.Security;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;

import org.apache.log4j.Logger;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import com.sun.crypto.provider.SunJCE;

public class DesUtil {
	private static final Logger logger = Logger.getLogger(DesUtil.class);
	private static final String ALGORITHM = "DES";

	private KeyGenerator keyGenerator;
	private SecretKey secretKey;
	private Cipher cipher;

	public DesUtil(String key) {
		this.init(key);
	}

	private void init(String key) {
		Security.addProvider(new SunJCE());
		try {
			this.keyGenerator = KeyGenerator.getInstance(ALGORITHM);
			this.keyGenerator.init(new SecureRandom(key.getBytes()));
			this.secretKey = this.keyGenerator.generateKey();
			this.cipher = Cipher.getInstance(ALGORITHM);
		} catch (NoSuchAlgorithmException e) {
			logger.error(e);
		} catch (NoSuchPaddingException e) {
			logger.error(e);
		}

	}

	/**
	 * 加密
	 * @param expreStr
	 * @return
	 */
	public String encry(String expreStr) {
		byte[] cipByte = null;// 密文数组
		byte[] expreByte = null;// 明文数组
		String cipStr = ""; // 密文
		BASE64Encoder base64Encoder = new BASE64Encoder();
		try {
			expreByte = expreStr.getBytes("UTF-8");
			this.cipher.init(Cipher.ENCRYPT_MODE, this.secretKey);
			cipByte = this.cipher.doFinal(expreByte);
			cipStr = base64Encoder.encode(cipByte);
		} catch (UnsupportedEncodingException e) {
			logger.error(e);
		} catch (InvalidKeyException e) {
			logger.error(e);
		} catch (IllegalBlockSizeException e) {
			logger.error(e);
		} catch (BadPaddingException e) {
			logger.error(e);
		}
		return cipStr;
	}

	/**
	 * 解密
	 * @param cipStr
	 * @return
	 */
	public String decry(String cipStr) {
		byte[] cipByte = null;// 密文数组
		byte[] expreByte = null; // 明文数组
		String expreStr = "";// 明文
		BASE64Decoder base64Decoder = new BASE64Decoder();
		try {
			cipByte = base64Decoder.decodeBuffer(cipStr);
			this.cipher.init(Cipher.DECRYPT_MODE, this.secretKey);
			expreByte = this.cipher.doFinal(cipByte);
			expreStr = new String(expreByte, "UTF-8");
		} catch (IOException e) {
			logger.error(e);
		} catch (InvalidKeyException e) {
			logger.error(e);
		} catch (IllegalBlockSizeException e) {
			logger.error(e);
		} catch (BadPaddingException e) {
			logger.error(e);
		}
		return expreStr;
	}
	
	public static void main(String[] args) {
		String pwd = "12345 6";
		System.out.println("加密前：" + pwd);
		DesUtil desUtil = new DesUtil("abc");
		String encStr = desUtil.encry(pwd);
		System.out.println("加密后：" + encStr);
		String decStr = desUtil.decry(encStr);
		System.out.println("解密后：" + decStr);
	}
}