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3DES算法简介
3DES又称Triple DES，是DES加密算法的一种模式，它使用两条不同的56位密钥对数据进行三次加密。
DES使用56位密钥和密码块的方法，而在密码块的方法中，文本被分成64位大小的文本块然后再进行加密。相对DES，3DES更为安全。
3DES是DES向AES过渡的加密算法，其具体实现如下：
设Ek()和Dk()代表DES算法的加密和解密过程，K代表DES算法使用的密钥，M代表明文，C代表密文，这样：
· 3DES加密过程为：C=Ek3(Dk2(Ek1(M)))。
· 3DES解密过程为：M=Dk1(Ek2(Dk3©))。
关于3DES概念性的内容不做过多介绍，大家可以自行百度。
Maven 依赖
工具类对于加密后使用Base64进行编码，所以需要依赖Apache Commons Codec。
<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
<version>1.9</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
工具类实现
DES3Util提供了针对文本内容、字节数组内容的加解密实现，DES3Util工具类可以直接复制使用，代码如下：
package com.arhorchin.securitit.enordecryption.des;
import java.security.Key;
import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import javax.crypto.spec.IvParameterSpec;
import org.apache.commons.codec.binary.Base64;
import org.apache.log4j.Logger;
/**
* @author Securitit.
* @note 3DES加密算法实现.
*/
public class DES3Util {
/**
* logger.
*/
private static Logger logger = Logger.getLogger(DES3Util.class);
/**
* 数据编码.
*/
private static final String CHARSET_UTF8 = "UTF-8";
/**
* 算法编号.
*/
public static final String DES3_NAME = "DESEDE";
/**
* CBC模式串.
*/
public static final String DES3_NAME_ECB = "desede/CBC/PKCS5Padding";
/**
* 初始向量.
*/
public static final byte[] DES3_KEY_IV = {
1, 2, 3, 4, 5, 6, 7, 8 };
/**
* 根据密码生成Key.要求：密码长度不得小于24.
* @param des3KeyPwd 密码字符串.
* @return 3DES密钥.
* @throws Exception 可能异常.
*/
public static String generateDes3Key(String des3KeyPwd) throws Exception {
DESedeKeySpec des3KeySpec = null;
SecretKeyFactory keyFactory = null;
byte[] keyBytes = null;
des3KeySpec = new DESedeKeySpec(des3KeyPwd.getBytes(CHARSET_UTF8));
keyFactory = SecretKeyFactory.getInstance(DES3_NAME);
keyBytes = keyFactory.generateSecret(des3KeySpec).getEncoded();
return Base64.encodeBase64String(keyBytes);
}
/**
* 对文本内容进行加密.
* @param plainText 待加密明文内容.
* @param des3Key 3DES密钥.
* @return 加密的密文.
*/
public static String encodeText(String plainText, String des3Key) throws Exception {
byte[] des3KeyBytes = null;
byte[] plainBytes = null;
byte[] cipherBytes = null;
try {
des3KeyBytes = Base64.decodeBase64(des3Key);
plainBytes = plainText.getBytes(CHARSET_UTF8);
cipherBytes = encodeByCbc(plainBytes, des3KeyBytes, DES3_KEY_IV);
return Base64.encodeBase64String(cipherBytes);
} catch (Exception ex) {
logger.error("DES3Util.encodeText.", ex);
return "";
}
}
/**
* 对文本密文进行解密.
* @param cipherText 待解密密文.
* @param des3Key 3DES密钥.
* @return 解密的明文.
*/
public static String decodeText(String cipherText, String des3Key) throws Exception {
byte[] des3KeyBytes = null;
byte[] cipherBytes = null;
byte[] plainBytes = null;
try {
des3KeyBytes = Base64.decodeBase64(des3Key);
cipherBytes = Base64.decodeBase64(cipherText);
plainBytes = decodeByCbc(cipherBytes, des3KeyBytes, DES3_KEY_IV);
return new String(plainBytes, CHARSET_UTF8);
} catch (Exception ex) {
logger.error("DESUtil.decodeText.", ex);
return "";
}
}
/**
* 对字节数组内容进行加密.
* @param plainText 待加密明文内容.
* @param dseKey 3DES密钥.
* @return 加密的密文.
*/
public static byte[] encodeBytes(byte[] plainBytes, String des3Key) throws Exception {
byte[] desKeyBytes = null;
byte[] cipherBytes = null;
try {
desKeyBytes = Base64.decodeBase64(des3Key);
cipherBytes = encodeByCbc(plainBytes, desKeyBytes, DES3_KEY_IV);
return cipherBytes;
} catch (Exception ex) {
logger.error("DESUtil.encodeBytes.", ex);
return new byte[0];
}
}
/**
* 对字节数组密文进行解密.
* @param cipherText 待解密密文.
* @param des3Key 3DES密钥.
* @return 解密的明文.
*/
public static byte[] decodeBytes(byte[] cipherBytes, String des3Key) throws Exception {
byte[] desKeyBytes = null;
byte[] plainBytes = null;
try {
desKeyBytes = Base64.decodeBase64(des3Key);
plainBytes = decodeByCbc(cipherBytes, desKeyBytes, DES3_KEY_IV);
return plainBytes;
} catch (Exception ex) {
logger.error("DESUtil.decodeBytes.", ex);
return new byte[0];
}
}
/**
* 3DES算法使用CBC模式进行加密.
* @param plainBytes 原文内容.
* @param des3Key 3DES密钥.
* @param keyIv 3DES初始向量.
* @return 加密后的内容.
* @throws Exception .
*/
public static byte[] encodeByCbc(byte[] plainBytes, byte[] des3Key, byte[] keyIv) throws Exception {
Key deskey = null;
DESedeKeySpec desSpec = null;
SecretKeyFactory keyFactory = null;
Cipher cipher = null;
IvParameterSpec ivSpec = null;
byte[] cipherOut = null;
desSpec = new DESedeKeySpec(des3Key);
keyFactory = SecretKeyFactory.getInstance(DES3_NAME);
deskey = keyFactory.generateSecret(desSpec);
cipher = Cipher.getInstance(DES3_NAME_ECB);
ivSpec = new IvParameterSpec(keyIv);
cipher.init(Cipher.ENCRYPT_MODE, deskey, ivSpec);
cipherOut = cipher.doFinal(plainBytes);
return cipherOut;
}
/**
* 3DES算法使用CBC模式进行解密.
* @param plainBytes 密文内容.
* @param des3Key 3DES密钥.
* @param keyIv 3DES初始向量.
* @return 解密后的内容.
* @throws Exception .
*/
public static byte[] decodeByCbc(byte[] plainBytes, byte[] des3Key, byte[] keyIv) throws Exception {
Key deskey = null;
DESedeKeySpec desSpec = null;
SecretKeyFactory keyFactory = null;
Cipher cipher = null;
IvParameterSpec ivSpec = null;
byte[] cipherOut = null;
desSpec = new DESedeKeySpec(des3Key);
keyFactory = SecretKeyFactory.getInstance(DES3_NAME);
deskey = keyFactory.generateSecret(desSpec);
cipher = Cipher.getInstance(DES3_NAME_ECB);
ivSpec = new IvParameterSpec(keyIv);
cipher.init(Cipher.DECRYPT_MODE, deskey, ivSpec);
cipherOut = cipher.doFinal(plainBytes);
return cipherOut;
}
}
工具类测试
package com.arhorchin.securitit.enordecryption.des;
import java.util.Arrays;
/**
* @author Securitit.
* @note TripleDES3Util测试类.
*/
public class DES3UtilTester {
public static void main(String[] args) throws Exception {
String desKeyPwd = "123456788765432112345678";
String desKey = null;
String plainText = "This is 一段明文内容！";
String cipherText = null;
System.out.println("----------------------- 获取DES秘钥 -------------------------");
desKey = DES3Util.generateDes3Key(desKeyPwd);
System.out.println("秘钥：" + desKey);
System.out.println();
// 文本加解密测试.
System.out.println("----------------------- 文本加解密测试 -------------------------");
System.out.println("明文：" + plainText);
cipherText = DES3Util.encodeText(plainText, desKey);
System.out.println("密文：" + cipherText);
plainText = DES3Util.decodeText(cipherText, desKey);
System.out.println("解密明文：" + plainText);
System.out.println();
System.out.println("----------------------- 字节数组加解密测试 -------------------------");
byte[] plainBytes = plainText.getBytes("UTF-8");
byte[] cipherBytes = null;
System.out.println("明文：" + Arrays.toString(plainBytes));
cipherBytes = DES3Util.encodeBytes(plainBytes, desKey);
System.out.println("密文：" + Arrays.toString(cipherBytes));
plainBytes = DES3Util.decodeBytes(cipherBytes, desKey);
System.out.println("解密明文：" + Arrays.toString(plainBytes));
System.out.println();
}
}
控制台输出
查看Console中的控制台内容，明文和解密后明文对比，可以确认DES3Util可以正常工作，控制台如下图：
----------------------- 获取DES秘钥 -------------------------
秘钥：MTIyNDQ3Nzg4Nzc0NDIyMTEyMjQ0Nzc4
----------------------- 文本加解密测试 -------------------------
明文：This is 一段明文内容！
密文：JxYMtG6qIvxci4gDOtBSV4YG4FQhDatKk5k8edb2res=
解密明文：This is 一段明文内容！
----------------------- 字节数组加解密测试 -------------------------
明文：[84, 104, 105, 115, 32, 105, 115, 32, -28, -72, -128, -26, -82, -75, -26, -104, -114, -26, -106, -121, -27, -122, -123, -27, -82, -71, -17, -68, -127]
密文：[39, 22, 12, -76, 110, -86, 34, -4, 92, -117, -120, 3, 58, -48, 82, 87, -122, 6, -32, 84, 33, 13, -85, 74, -109, -103, 60, 121, -42, -10, -83, -21]
解密明文：[84, 104, 105, 115, 32, 105, 115, 32, -28, -72, -128, -26, -82, -75, -26, -104, -114, -26, -106, -121, -27, -122, -123, -27, -82, -71, -17, -68, -127]
总结
算法实现都很类似，本文只是对算法实现做了整理，在Maven依赖引入的情况下，DES3Util已经做了简单测试，可以直接使用。
若文中存在错误和不足，欢迎指正！
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