java加密 des
DES-Data Encryption Standard,即数据加密算法。是IBM公司于1975年研究成功并公开发表的。DES算法的入口参数有三个:Key、Data、Mode。其中Key为8个字节共64位,是DES算法的工作密钥;Data也为8个字节64位,是要被加密或被解密的数据;Mode为DES的工作方式,有两种:加密或解密。
DES算法把64位的明文输入块变为64位的密文输出块,它所使用的密钥也是64位。
import java.security.Key;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
/**
* DES安全编码组件
*
* <pre>
* 支持 DES、DESede(TripleDES,就是3DES)、AES、Blowfish、RC2、RC4(ARCFOUR)
* DES key size must be equal to 56
* DESede(TripleDES) key size must be equal to 112 or 168
* AES key size must be equal to 128, 192 or 256,but 192 and 256 bits may not be available
* Blowfish key size must be multiple of 8, and can only range from 32 to 448 (inclusive)
* RC2 key size must be between 40 and 1024 bits
* RC4(ARCFOUR) key size must be between 40 and 1024 bits
* 具体内容 需要关注 JDK Document http://.../docs/technotes/guides/security/SunProviders.html
* </pre>
*
* @author 梁栋
* @version 1.0
* @since 1.0
*/
public class DESTest extends Coder {
/**
* ALGORITHM 算法 <br>
* 可替换为以下任意一种算法，同时key值的size相应改变。
*
* <pre>
* DES key size must be equal to 56
* DESede(TripleDES) key size must be equal to 112 or 168
* AES key size must be equal to 128, 192 or 256,but 192 and 256 bits may not be available
* Blowfish key size must be multiple of 8, and can only range from 32 to 448 (inclusive)
* RC2 key size must be between 40 and 1024 bits
* RC4(ARCFOUR) key size must be between 40 and 1024 bits
* </pre>
*
* 在Key toKey(byte[] key)方法中使用下述代码
* <code>SecretKey secretKey = new SecretKeySpec(key, ALGORITHM);</code> 替换
* <code>
* DESKeySpec dks = new DESKeySpec(key);
* SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
* SecretKey secretKey = keyFactory.generateSecret(dks);
* </code>
*/
public static final String ALGORITHM = "DES";
/**
* 转换密钥<br>
*
* @param key
* @return
* @throws Exception
*/
private static Key toKey(byte[] key) throws Exception {
DESKeySpec dks = new DESKeySpec(key);
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
SecretKey secretKey = keyFactory.generateSecret(dks);
// 当使用其他对称加密算法时，如AES、Blowfish等算法时，用下述代码替换上述三行代码
// SecretKey secretKey = new SecretKeySpec(key, ALGORITHM);
return secretKey;
}
/**
* 解密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] decrypt(byte[] data, String key) throws Exception {
Key k = toKey(decryptBASE64(key));
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, k);
return cipher.doFinal(data);
}
/**
* 加密
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] encrypt(byte[] data, String key) throws Exception {
Key k = toKey(decryptBASE64(key));
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, k);
return cipher.doFinal(data);
}
/**
* 生成密钥
*
* @return
* @throws Exception
*/
public static String initKey() throws Exception {
return initKey(null);
}
/**
* 生成密钥
*
* @param seed
* @return
* @throws Exception
*/
public static String initKey(String seed) throws Exception {
SecureRandom secureRandom = null;
if (seed != null) {
secureRandom = new SecureRandom(decryptBASE64(seed));
} else {
secureRandom = new SecureRandom();
}
KeyGenerator kg = KeyGenerator.getInstance(ALGORITHM);
kg.init(secureRandom);
SecretKey secretKey = kg.generateKey();
return encryptBASE64(secretKey.getEncoded());
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
}
}
测试：
import static org.junit.Assert.*;
import org.junit.Test;
public class DESCoderTest2 {
@Test
public void test() throws Exception {
String inputStr = "DES";
String key = DESTest.initKey();
System.err.println("原文:/t" + inputStr);
System.err.println("密钥:/t" + key);
byte[] inputData = inputStr.getBytes();
inputData = DESTest.encrypt(inputData, key);
System.err.println("加密后:/t" + DESTest.encryptBASE64(inputData));
byte[] outputData = DESTest.decrypt(inputData, key);
String outputStr = new String(outputData);
System.err.println("解密后:/t" + outputStr);
assertEquals(inputStr, outputStr);
}
}
按着我理解的意思来进行再次分析：
import static org.junit.Assert.*;
import org.junit.Test;
public class DESCoderTest {
@Test
public void test() throws Exception {
String inputStr = "DES";
String key = DESTest.initKey();
System.err.println("原文:/t" + inputStr);
System.err.println("密钥:/t" + key);
byte[] inputData = inputStr.getBytes();
inputData = DESTest.encrypt(inputData, key);
System.err.println("des加密后:/t" + new String(inputData));
//进行加密
String encryptstr = DESTest.encryptBASE64(inputData);
System.err.println("base加密后:/t" + encryptstr);
//解密:
byte []b = DESTest.decryptBASE64(encryptstr);
System.err.println("base解密后:/t" + new String(b));
byte[] outputData = DESTest.decrypt(inputData, key);
String outputStr = new String(outputData);
System.err.println("des解密后:/t" + outputStr);
assertEquals(inputStr, outputStr);
}
}