Java之——实现微信小程序加密数据解密算法

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。

1<dependency>
2    <groupId>org.bouncycastle</groupId>
3    <artifactId>bcprov-jdk16</artifactId>
4    <version>1.46</version>
5</dependency>
6 
7 <dependency>
8    <groupId>commons-codec</groupId>
9    <artifactId>commons-codec</artifactId>
10    <version>1.4</version>
11</dependency>
12 
13<dependency> 
14    <groupId>net.sf.json-lib</groupId> 
15    <artifactId>json-lib</artifactId> 
16    <version>2.2.3</version> 
17    <classifier>jdk15</classifier> 
18</dependency>

3、实现AES类

1package com.chwl.medical.crypto.wx;
2 
3import java.security.AlgorithmParameters;
4import java.security.InvalidAlgorithmParameterException;
5import java.security.InvalidKeyException;
6import java.security.Key;
7import java.security.NoSuchAlgorithmException;
8import java.security.NoSuchProviderException;
9import java.security.Security;
10 
11import javax.crypto.BadPaddingException;
12import javax.crypto.Cipher;
13import javax.crypto.IllegalBlockSizeException;
14import javax.crypto.NoSuchPaddingException;
15import javax.crypto.spec.IvParameterSpec;
16import javax.crypto.spec.SecretKeySpec;
17import org.bouncycastle.jce.provider.BouncyCastleProvider;
18 
19/**
20 * AES加密
21 * @author liuyazhuang
22 *
23 */
24public class AES {
25    
26    public static boolean initialized = false;
27 
28    /**
29     * AES解密
30     * 
31     * @param content
32     *            密文
33     * @return
34     * @throws InvalidAlgorithmParameterException
35     * @throws NoSuchProviderException
36     */
37    public byte[] decrypt(byte[] content, byte[] keyByte, byte[] ivByte) throws InvalidAlgorithmParameterException {
38        initialize();
39        try {
40            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
41            Key sKeySpec = new SecretKeySpec(keyByte, "AES");
42            cipher.init(Cipher.DECRYPT_MODE, sKeySpec, generateIV(ivByte));// 初始化
43            byte[] result = cipher.doFinal(content);
44            return result;
45        } catch (NoSuchAlgorithmException e) {
46            e.printStackTrace();
47        } catch (NoSuchPaddingException e) {
48            e.printStackTrace();
49        } catch (InvalidKeyException e) {
50            e.printStackTrace();
51        } catch (IllegalBlockSizeException e) {
52            e.printStackTrace();
53        } catch (BadPaddingException e) {
54            e.printStackTrace();
55        } catch (NoSuchProviderException e) {
56            // TODO Auto-generated catch block
57            e.printStackTrace();
58        } catch (Exception e) {
59            // TODO Auto-generated catch block
60            e.printStackTrace();
61        }
62        return null;
63    }
64 
65    public static void initialize() {
66        if (initialized)
67            return;
68        Security.addProvider(new BouncyCastleProvider());
69        initialized = true;
70    }
71 
72    // 生成iv
73    public static AlgorithmParameters generateIV(byte[] iv) throws Exception {
74        AlgorithmParameters params = AlgorithmParameters.getInstance("AES");
75        params.init(new IvParameterSpec(iv));
76        return params;
77    }
78}

4、实现WxPKCS7Encoder类

1package com.chwl.medical.crypto.wx;
2 
3import java.nio.charset.Charset;
4import java.util.Arrays;
5 
6 
7/**
8 * 微信小程序加解密
9 * @author liuyazhuang
10 *
11 */
12public class WxPKCS7Encoder {
13    private static final Charset CHARSET = Charset.forName("utf-8");
14    private static final int BLOCK_SIZE = 32;
15 
16    /**
17     * 获得对明文进行补位填充的字节.
18     *
19     * @param count
20     *            需要进行填充补位操作的明文字节个数
21     * @return 补齐用的字节数组
22     */
23    public static byte[] encode(int count) {
24        // 计算需要填充的位数
25        int amountToPad = BLOCK_SIZE - (count % BLOCK_SIZE);
26        if (amountToPad == 0) {
27            amountToPad = BLOCK_SIZE;
28        }
29        // 获得补位所用的字符
30        char padChr = chr(amountToPad);
31        String tmp = new String();
32        for (int index = 0; index < amountToPad; index++) {
33            tmp += padChr;
34        }
35        return tmp.getBytes(CHARSET);
36    }
37 
38    /**
39     * 删除解密后明文的补位字符
40     *
41     * @param decrypted
42     *            解密后的明文
43     * @return 删除补位字符后的明文
44     */
45    public static byte[] decode(byte[] decrypted) {
46        int pad = decrypted[decrypted.length - 1];
47        if (pad < 1 || pad > 32) {
48            pad = 0;
49        }
50        return Arrays.copyOfRange(decrypted, 0, decrypted.length - pad);
51    }
52 
53    /**
54     * 将数字转化成ASCII码对应的字符，用于对明文进行补码
55     *
56     * @param a
57     *            需要转化的数字
58     * @return 转化得到的字符
59     */
60    public static char chr(int a) {
61        byte target = (byte) (a & 0xFF);
62        return (char) target;
63    }
64}

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。

1package com.chwl.medical.crypto.wx;
2 
3import org.apache.commons.codec.binary.Base64;
4 
5import net.sf.json.JSONObject;
6 
7 
8/**
9 * 封装对外访问方法
10 * @author liuyazhuang
11 *
12 */
13public class WXCore {
14    
15    private static final String WATERMARK = "watermark";
16    private static final String APPID = "appid";
17    /**
18     * 解密数据
19     * @return
20     * @throws Exception
21     */
22    public static String decrypt(String appId, String encryptedData, String sessionKey, String iv){
23        String result = "";
24        try {
25            AES aes = new AES();  
26            byte[] resultByte = aes.decrypt(Base64.decodeBase64(encryptedData), Base64.decodeBase64(sessionKey), Base64.decodeBase64(iv));  
27            if(null != resultByte && resultByte.length > 0){  
28                result = new String(WxPKCS7Encoder.decode(resultByte));  
29                JSONObject jsonObject = JSONObject.fromObject(result);
30                String decryptAppid = jsonObject.getJSONObject(WATERMARK).getString(APPID);
31                if(!appId.equals(decryptAppid)){
32                    result = "";
33                }
34            }  
35        } catch (Exception e) {
36            result = "";
37            e.printStackTrace();
38        }
39        return result;
40    }
41    
42    
43    public static void main(String[] args) throws Exception{
44       String appId = "wx4f4bc4dec97d474b";
45       String encryptedData = "CiyLU1Aw2KjvrjMdj8YKliAjtP4gsMZMQmRzooG2xrDcvSnxIMXFufNstNGTyaGS9uT5geRa0W4oTOb1WT7fJlAC+oNPdbB+3hVbJSRgv+4lGOETKUQz6OYStslQ142dNCuabNPGBzlooOmB231qMM85d2/fV6ChevvXvQP8Hkue1poOFtnEtpyxVLW1zAo6/1Xx1COxFvrc2d7UL/lmHInNlxuacJXwu0fjpXfz/YqYzBIBzD6WUfTIF9GRHpOn/Hz7saL8xz+W//FRAUid1OksQaQx4CMs8LOddcQhULW4ucetDf96JcR3g0gfRK4PC7E/r7Z6xNrXd2UIeorGj5Ef7b1pJAYB6Y5anaHqZ9J6nKEBvB4DnNLIVWSgARns/8wR2SiRS7MNACwTyrGvt9ts8p12PKFdlqYTopNHR1Vf7XjfhQlVsAJdNiKdYmYVoKlaRv85IfVunYzO0IKXsyl7JCUjCpoG20f0a04COwfneQAGGwd5oa+T8yO5hzuyDb/XcxxmK01EpqOyuxINew==";
46       String sessionKey = "tiihtNczf5v6AKRyjwEUhQ==";
47       String iv = "r7BXXKkLb8qrSNn05n0qiA==";
48       System.out.println(decrypt(appId, encryptedData, sessionKey, iv));
49    }
50}