您的位置：首页 > 其它

对称加密中DES的加密与解密算法

2017-12-20 16:42 507 查看

package Encoder.symmetry;

import java.security.InvalidKeyException;

import java.security.NoSuchAlgorithmException;

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 javax.crypto.spec.SecretKeySpec;

/**

* 对称加密算法可逆加密算法

* DES/3DES/AES的不同加密算法

* @author CUICHUNCHI

*

*DES:通过keygenerator获取密钥生成器实例后，设置des的算法密钥为56，便可生成密钥

*并且每次生成的密钥都不相同，为了存储，将其密钥通过base64编码转为字符串，将密钥字符串解码后实例化SecretKey

*，只需要实例化SecretKeySpec即可，返回一个SecretKey

*加密与解密都需要Cipher对象，初始化时，需要传入加密与解密对应的模式，（Cipher.ENCRYPT_MODE/Cipher.DECRYPT_MODE）

*以及传入对应的SecretKey密钥即可加密与解密

*/

public class DESUtil {

private static final String DES = "DES";

/**
* 生成 DES 的密钥
* @throws NoSuchAlgorithmException
*/
public static byte[] getKeyDES() throws NoSuchAlgorithmException{
KeyGenerator key = KeyGenerator.getInstance(DES);
key.init(56);
SecretKey generateKey = key.generateKey();
byte[] encoded = generateKey.getEncoded();

// StringBuffer hexValue = new StringBuffer();

/* for (int i = 0; i < encoded.length; i++) {

int val = ((int) encoded[i]) & 0xff;

if (val < 16) {

hexValue.append("0");

}

hexValue.append(Integer.toHexString(val));

}*/

return encoded;
}
//加载生成一个SecrectKeySpec的实例，返回一个密钥SecretKey
private static SecretKey loadKeyDES(byte [] desStr){
SecretKey key = new SecretKeySpec(desStr,"DES");
return key;
}
/**
* 对原始字符进行DES加密
* @param str
* @param key
* @return
* @throws NoSuchAlgorithmException
* @throws NoSuchPaddingException
* @throws InvalidKeyException
* @throws IllegalBlockSizeException
* @throws BadPaddingException
*/
public static byte[] encryptDES(String str,SecretKey key) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException{
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] doFinal = cipher.doFinal(str.getBytes());
return doFinal;
}

/**
* 解密
* @param b
* @return
* @throws NoSuchPaddingException
* @throws NoSuchAlgorithmException
* @throws InvalidKeyException
* @throws BadPaddingException
* @throws IllegalBlockSizeException
*/
public static String decryptDES(byte [] b,SecretKey key) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException{
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.DECRYPT_MODE, key);
byte[] doFinal = cipher.doFinal(b);
return new String(doFinal);
}

public static void main(String[] args) throws NoSuchAlgorithmException, InvalidKeyException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {
String str ="崔春驰";
//生成密钥
byte[] keyStr = DESUtil.getKeyDES();
SecretKey key = loadKeyDES(keyStr);
System.out.println("生成的密钥："+key);
//调用加密
byte[] encryptDES = encryptDES(str, key);
System.out.println("加密后:"+encryptDES);
String decryptDES = decryptDES(encryptDES, key);
System.out.println("解密："+decryptDES);
}

}

内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理

标签：

相关文章推荐

新的分享

章节导航