转载请注明出处：http://blog.csdn.net/l1028386804/article/details/79450115
一、概述
微信推出了小程序，很多公司的客户端应用不仅具有了APP、H5、还接入了小程序开发。但是，小程序中竟然没有提供Java版本的加密数据解密算法。这着实让广大的Java开发人员蛋疼。
微信小程序提供的加密数据解密算法链接为：https://mp.weixin.qq.com/debug/wxadoc/dev/api/signature.html
最新地址为：https://developers.weixin.qq.com/miniprogram/dev/framework/open-ability/signature.html
我们下载的算法示例如下：
木有Java！！ 木有Java！！ 木有Java！！
那么如何解决这个问题，我们一起来实现Java版本的微信小程序加密数据解密算法。
二、实现Java版本的微信小程序加密数据解密算法
1、创建项目
这里，我们创建一个Maven工程，具体创建步骤略。
2、配置pom.xml
我们在pom.xml中加入如下配置。
<dependency>
<groupId>org.bouncycastle</groupId>
<artifactId>bcprov-jdk16</artifactId>
<version>1.46</version>
</dependency>
<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
<version>1.4</version>
</dependency>
<dependency>
<groupId>net.sf.json-lib</groupId>
<artifactId>json-lib</artifactId>
<version>2.2.3</version>
<classifier>jdk15</classifier>
</dependency>
3、实现AES类
package com.chwl.medical.crypto.wx;
import java.security.AlgorithmParameters;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Security;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
/**
* AES加密
* @author liuyazhuang
*
*/
public class AES {
public static boolean initialized = false;
/**
* AES解密
*
* @param content
* 密文
* @return
* @throws InvalidAlgorithmParameterException
* @throws NoSuchProviderException
*/
public byte[] decrypt(byte[] content, byte[] keyByte, byte[] ivByte) throws InvalidAlgorithmParameterException {
initialize();
try {
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
Key sKeySpec = new SecretKeySpec(keyByte, "AES");
cipher.init(Cipher.DECRYPT_MODE, sKeySpec, generateIV(ivByte));// 初始化
byte[] result = cipher.doFinal(content);
return result;
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
} catch (NoSuchProviderException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
public static void initialize() {
if (initialized)
return;
Security.addProvider(new BouncyCastleProvider());
initialized = true;
}
// 生成iv
public static AlgorithmParameters generateIV(byte[] iv) throws Exception {
AlgorithmParameters params = AlgorithmParameters.getInstance("AES");
params.init(new IvParameterSpec(iv));
return params;
}
}
4、实现WxPKCS7Encoder类
package com.chwl.medical.crypto.wx;
import java.nio.charset.Charset;
import java.util.Arrays;
/**
* 微信小程序加解密
* @author liuyazhuang
*
*/
public class WxPKCS7Encoder {
private static final Charset CHARSET = Charset.forName("utf-8");
private static final int BLOCK_SIZE = 32;
/**
* 获得对明文进行补位填充的字节.
*
* @param count
* 需要进行填充补位操作的明文字节个数
* @return 补齐用的字节数组
*/
public static byte[] encode(int count) {
// 计算需要填充的位数
int amountToPad = BLOCK_SIZE - (count % BLOCK_SIZE);
if (amountToPad == 0) {
amountToPad = BLOCK_SIZE;
}
// 获得补位所用的字符
char padChr = chr(amountToPad);
String tmp = new String();
for (int index = 0; index < amountToPad; index++) {
tmp += padChr;
}
return tmp.getBytes(CHARSET);
}
/**
* 删除解密后明文的补位字符
*
* @param decrypted
* 解密后的明文
* @return 删除补位字符后的明文
*/
public static byte[] decode(byte[] decrypted) {
int pad = decrypted[decrypted.length - 1];
if (pad < 1 || pad > 32) {
pad = 0;
}
return Arrays.copyOfRange(decrypted, 0, decrypted.length - pad);
}
/**
* 将数字转化成ASCII码对应的字符，用于对明文进行补码
*
* @param a
* 需要转化的数字
* @return 转化得到的字符
*/
public static char chr(int a) {
byte target = (byte) (a & 0xFF);
return (char) target;
}
}
5、实现WXCore类
这个类主要是对具体算法的封装，统一对外提供方法。
package com.chwl.medical.crypto.wx;
import org.apache.commons.codec.binary.Base64;
import net.sf.json.JSONObject;
/**
* 封装对外访问方法
* @author liuyazhuang
*
*/
public class WXCore {
private static final String WATERMARK = "watermark";
private static final String APPID = "appid";
/**
* 解密数据
* @return
* @throws Exception
*/
public static String decrypt(String appId, String encryptedData, String sessionKey, String iv){
String result = "";
try {
AES aes = new AES();
byte[] resultByte = aes.decrypt(Base64.decodeBase64(encryptedData), Base64.decodeBase64(sessionKey), Base64.decodeBase64(iv));
if(null != resultByte && resultByte.length > 0){
result = new String(WxPKCS7Encoder.decode(resultByte));
JSONObject jsonObject = JSONObject.fromObject(result);
String decryptAppid = jsonObject.getJSONObject(WATERMARK).getString(APPID);
if(!appId.equals(decryptAppid)){
result = "";
}
}
} catch (Exception e) {
result = "";
e.printStackTrace();
}
return result;
}
public static void main(String[] args) throws Exception{
String appId = "wx4f4bc4dec97d474b";
String encryptedData = "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";
String sessionKey = "tiihtNczf5v6AKRyjwEUhQ==";
String iv = "r7BXXKkLb8qrSNn05n0qiA==";
System.out.println(decrypt(appId, encryptedData, sessionKey, iv));
}
}
