java微信小程序解密AES/CBC/PKCS7Padding

微信小程序解密 
建议使用1.6及以上的环境 
使用maven下载jar包

<!--  -->  
  <dependency>  
    <groupId>org.bouncycastle</groupId>  
    <artifactId>bcprov-jdk15on</artifactId>  
    <version>1.55</version>  
  </dependency>  

加密类代码

import org.bouncycastle.jce.provider.BouncyCastleProvider;  
import org.bouncycastle.util.Arrays;  
import javax.crypto.Cipher;  
import javax.crypto.NoSuchPaddingException;  
import javax.crypto.spec.IvParameterSpec;  
import javax.crypto.spec.SecretKeySpec;  
import java.security.Key;  
import java.security.NoSuchAlgorithmException;  
import java.security.NoSuchProviderException;  
import java.security.Security;  
/**  
 * Created by wind on 2016/12/24.  
 */  
/**  
 *  
 * @author ngh  
 * AES128 算法  
 *  
 * CBC 模式  
 *  
 * PKCS7Padding 填充模式  
 *  
 * CBC模式需要添加一个参数iv--对称解密算法初始向量 iv  
 *  
 * 介于java 不支持PKCS7Padding，只支持PKCS5Padding 但是PKCS7Padding 和 PKCS5Padding 没有什么区别  
 * 要实现在java端用PKCS7Padding填充，需要用到bouncycastle组件来实现  
 */  
public class Pkcs7Encoder {  
    // 算法名称  
    static  final String KEY_ALGORITHM = "AES";  
    // 加解密算法/模式/填充方式  
    static  final String algorithmStr = "AES/CBC/PKCS7Padding";  
    private static Key key;  
    private static Cipher cipher;  
    boolean isInited = false;  
    //默认对称解密算法初始向量 iv  
    static byte[] iv = { 0x30, 0x31, 0x30, 0x32, 0x30, 0x33, 0x30, 0x34, 0x30, 0x35, 0x30, 0x36, 0x30, 0x37, 0x30, 0x38 };  
    public static void init(byte[] keyBytes) {  
        // 如果密钥不足16位，那么就补足.  这个if 中的内容很重要  
        int base = 16;  
        if (keyBytes.length % base != 0) {  
            int groups = keyBytes.length / base + (keyBytes.length % base != 0 ? 1 : 0);  
            byte[] temp = new byte[groups * base];  
            Arrays.fill(temp, (byte) 0);  
            System.arraycopy(keyBytes, 0, temp, 0, keyBytes.length);  
            keyBytes = temp;  
        }  
        // 初始化  
        Security.addProvider(new BouncyCastleProvider());  
        // 转化成JAVA的密钥格式  
        key = new SecretKeySpec(keyBytes, KEY_ALGORITHM);  
        try {  
            // 初始化cipher  
            cipher = Cipher.getInstance(algorithmStr, "BC");  
        } catch (NoSuchAlgorithmException e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        } catch (NoSuchPaddingException e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        } catch (NoSuchProviderException e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        }  
    }  
    /**  
     * 加密方法  
     *      --使用默认iv时  
     * @param content  
     *            要加密的字符串  
     * @param keyBytes  
     *            加密密钥  
     * @return  
     */  
    public static byte[] encrypt(byte[] content, byte[] keyBytes) {  
        byte[] encryptedText =  encryptOfDiyIV(content,keyBytes,iv);  
        return encryptedText;  
    }  
    /**  
     * 解密方法  
     *      --使用默认iv时  
     * @param encryptedData  
     *            要解密的字符串  
     * @param keyBytes  
     *            解密密钥  
     * @return  
     */  
    public static byte[] decrypt(byte[] encryptedData, byte[] keyBytes) {  
        byte[] encryptedText = decryptOfDiyIV(encryptedData,keyBytes,iv);  
        return encryptedText;  
    }  
    /**  
     * 加密方法  
     *      ---自定义对称解密算法初始向量 iv  
     * @param content  
     *              要加密的字符串  
     * @param keyBytes  
     *              加密密钥  
     * @param ivs  
     *         自定义对称解密算法初始向量 iv  
     * @return 加密的结果  
     */  
    public static byte[] encryptOfDiyIV(byte[] content, byte[] keyBytes, byte[] ivs) {  
        byte[] encryptedText = null;  
        init(keyBytes);  
        System.out.println("IV：" + new String(ivs));  
        try {  
            cipher.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(ivs));  
            encryptedText = cipher.doFinal(content);  
        } catch (Exception e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        }  
        return encryptedText;  
    }  
    /**  
     * 解密方法  
     *  
     * @param encryptedData  
     *            要解密的字符串  
     * @param keyBytes  
     *            解密密钥  
     * @param ivs  
     *         自定义对称解密算法初始向量 iv  
     * @return  
     */  
    public static byte[] decryptOfDiyIV(byte[] encryptedData, byte[] keyBytes,byte[] ivs) {  
        byte[] encryptedText = null;  
        init(keyBytes);  
        System.out.println("IV：" + new String(ivs));  
        try {  
            cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(ivs));  
            encryptedText = cipher.doFinal(encryptedData);  
        } catch (Exception e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        }  
        return encryptedText;  
    }  
}  

测试类

public class Test {  
    public static void main(String[] args) throws Exception {   
        String  encryptedData = "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";  
        String iv="r7BXXKkLb8qrSNn05n0qiA==";  
        String sessionKey = "tiihtNczf5v6AKRyjwEUhQ==";  
        toStr(sessionKey,encryptedData,iv);  
    }  
    private static void  toStr(String sessionKey,String  encryptedData ,String iv) throws Exception{  
        byte[] sessionKeyBy = BASE64.decryptBASE64(sessionKey.getBytes());  
        byte[] encryptedDataBy = BASE64.decryptBASE64(encryptedData.getBytes());  
        byte[] ivBy = BASE64.decryptBASE64(iv.getBytes());  
        byte[] dec = Pkcs7Encoder.decryptOfDiyIV(encryptedDataBy, sessionKeyBy,ivBy);  
        System.out.println(new String(dec));  
    }  
}  

测试类中的Base64 带测试方法

import org.apache.commons.codec.binary.Base64;  
/** * BASE64加密解密 */    
public class BASE64 {    
    /** * BASE64解密 * @param key * @return * @throws Exception */    
    public static byte[] decryptBASE64(byte[] key) throws Exception {    
        return (new Base64()).decode(key);    
    }    
    /** * BASE64加密 * @param key * @return * @throws Exception */    
    public static byte[] encryptBASE64(byte[] key) throws Exception {    
        return (new Base64()).encode(key);    
    }    
    public static void main(String[] args) throws Exception {    
         byte[] data = BASE64.encryptBASE64("".getBytes());    
        System.out.println("加密前：" + new String(data));    
        byte[] byteArray = BASE64.decryptBASE64(data);    
        System.out.println("解密后：" + new String(byteArray));    
    }    
}    

完成

会出现的一些错误： 
cannot load mian class 
打包成jar包以后，在正式运行执行：Java bcprov-jdk150on-1.55.jar之前，需要删除 .jar包中的一个文件：META-INF/BCKEY.DSA 
no such provider: BC 
在jdk中的jre\lib\security修改java.security文件， security.provider.6=com.sun.security.sasl.Provider 下面添加 security.provider.7=org.bouncycastle.jce.provider.BouncyCastleProvider 
在\jre\lib\ext中添加bcprov-jdk15-135.jar的jar包 
bcprov-jdk16-143.jar提供加密，解密，生成密钥对等方法

下载网址： 
文件下载：bcprov-jdk15(16)-135(143).rar

文章大部分代码来自