des 加解密的封装和 使用的例子.txt

本文介绍了在JAVA开发环境中如何对文件和数据进行有效的加密

DES 加解密的封装和 使用的例子（转）

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DES加密封装 

package org.jtool.desutils; 
import java.security.SecureRandom; 
import javax.crypto.*; 
import javax.crypto.spec.DESKeySpec; 
public class DESEncrypt { 
private byte[] desKey; 
public DESEncrypt(byte[] desKey) { 
this.desKey = desKey; 
} 
public byte[] doEncrypt(byte[] plainText) throws Exception { 
// DES算法要求有一个可信任的随机数源 
SecureRandom sr = new SecureRandom(); 
byte rawKeyData[] = desKey;/* 用某种方法获得密匙数据 */ 
// 从原始密匙数据创建DESKeySpec对象 
DESKeySpec dks = new DESKeySpec(rawKeyData); 
// 创建一个密匙工厂，然后用它把DESKeySpec转换成 
// 一个SecretKey对象 
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES"); 
SecretKey key = keyFactory.generateSecret(dks); 
// Cipher对象实际完成加密操作 
Cipher cipher = Cipher.getInstance("DES"); 
// 用密匙初始化Cipher对象 
cipher.init(Cipher.ENCRYPT_MODE, key, sr); 
// 现在，获取数据并加密 
byte data[] = plainText;/* 用某种方法获取数据 */ 
// 正式执行加密操作 
byte encryptedData[] = cipher.doFinal(data); 
return encryptedData; 
} 
} 


DES解密封装 

package org.jtool.desutils; 
import java.security.SecureRandom; 
import javax.crypto.*; 
import javax.crypto.spec.DESKeySpec; 
public class DESDecrypt { 
private byte[] desKey; 
public DESDecrypt(byte[] desKey) { 
this.desKey = desKey; 
} 
public byte[] doDecrypt(byte[] encryptText) throws Exception { 
// DES算法要求有一个可信任的随机数源 
SecureRandom sr = new SecureRandom(); 
byte rawKeyData[] = desKey; /* 用某种方法获取原始密匙数据 */ 
// 从原始密匙数据创建一个DESKeySpec对象 
DESKeySpec dks = new DESKeySpec(rawKeyData); 
// 创建一个密匙工厂，然后用它把DESKeySpec对象转换成 
// 一个SecretKey对象 
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES"); 
SecretKey key = keyFactory.generateSecret(dks); 
// Cipher对象实际完成解密操作 
Cipher cipher = Cipher.getInstance("DES"); 
// 用密匙初始化Cipher对象 
cipher.init(Cipher.DECRYPT_MODE, key, sr); 
// 现在，获取数据并解密 
byte encryptedData[] = encryptText;/* 获得经过加密的数据 */ 
// 正式执行解密操作 
byte decryptedData[] = cipher.doFinal(encryptedData); 
return decryptedData; 
} 
} 


DES加解密使用样例 

package org.jtool.desutils; 
/** 
* 
*/ 
public class DESTest { 
public static void main(String[] args) throws Exception { 
String key = "ABCDEFGH"; 
String value = "AABBCCDDEE"; 
DESEncrypt desEncrypt = new DESEncrypt(key.getBytes()); 
byte[] encryptText = desEncrypt.doEncrypt(value.getBytes()); 
System.out.println("doEncrypt - " + toHexString(encryptText)); 
System.out.println("doEncrypt - " + new String(encryptText)); 
DESDecrypt desDecrypt = new DESDecrypt(key.getBytes()); 
byte[] decryptText = desDecrypt.doDecrypt(encryptText); 
System.out.println("doDecrypt - " + new String(decryptText)); 
System.out.println("doDecrypt - " + toHexString(decryptText)); 
} 
/** 
* 16进制显示数据 
* 
* @param value 字节数组 
* @return 
*/ 
public static String toHexString(byte[] value) { 
String newString = ""; 
for (int i = 0; i < value.length; i++) { 
byte b = value[i]; 
String str = Integer.toHexString(b); 
if (str.length() > 2) { 
str = str.substring(str.length() - 2); 
} 
if (str.length() < 2) { 
str = "0" + str; 
} 
newString += str; 
} 
return newString.toUpperCase(); 
} 
}