微信小程序解密过程(java)

方法一

package com.ecarpo.bms.wx.common;
 
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;
  }
}

　　

package com.ecarpo.bms.wx.common;

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));
    }
}

　　

package com.ecarpo.bms.wx.common;

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;
  }
}

　　引入maven依赖:

package com.ecarpo.bms.wx.common;

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;
  }
}

　　

方法二

package com.ecarpo.bms.wx.utils;

import java.io.UnsupportedEncodingException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.Security;
import java.util.Arrays;

import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

public class WxAESUtils {

  //算法名称
  final String KEY_ALGORITHM = "AES";

  // 加解密算法/模式/填充方式
  final String algorithmStr = "AES/CBC/PKCS7Padding";

  private Key key;

  private Cipher cipher;

  /**
   * 解密
   * 
   * @param encryptedDataStr
   * @param keyBytesStr
   * @param ivStr
   * @return
   * @author wangyue
   * @since 2018.08.15
   */
  public byte[] decrypt(String encryptedDataStr, String keyBytesStr, String ivStr) {
    byte[] encryptedText = null;
    byte[] encryptedData = null;
    byte[] sessionkey = null;
    byte[] iv = null;

    try {
      sessionkey = Base64.decodeBase64(keyBytesStr);
      encryptedData = Base64.decodeBase64(encryptedDataStr);
      iv = Base64.decodeBase64(ivStr);

      init(sessionkey);

      cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(iv));
      encryptedText = cipher.doFinal(encryptedData);
    } catch (Exception e) {
      e.printStackTrace();
    }
    return encryptedText;
  }

  public 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);
    } catch (NoSuchAlgorithmException e) {
      e.printStackTrace();
    } catch (NoSuchPaddingException e) {
      e.printStackTrace();
    }
  }

  public static void main(String[] args) {
    WxAESUtils s = new WxAESUtils();
    String encryptedDataStr = "CiyLU1Aw2KjvrjMdj8YKliAjtP4gsMZM\"\n"
        + "    \"QmRzooG2xrDcvSnxIMXFufNstNGTyaGS\"\n"
        + "    \"9uT5geRa0W4oTOb1WT7fJlAC+oNPdbB+\"\n"
        + "    \"3hVbJSRgv+4lGOETKUQz6OYStslQ142d\"\n"
        + "    \"NCuabNPGBzlooOmB231qMM85d2/fV6Ch\"\n"
        + "    \"evvXvQP8Hkue1poOFtnEtpyxVLW1zAo6\"\n"
        + "    \"/1Xx1COxFvrc2d7UL/lmHInNlxuacJXw\"\n"
        + "    \"u0fjpXfz/YqYzBIBzD6WUfTIF9GRHpOn\"\n"
        + "    \"/Hz7saL8xz+W//FRAUid1OksQaQx4CMs\"\n"
        + "    \"8LOddcQhULW4ucetDf96JcR3g0gfRK4P\"\n"
        + "    \"C7E/r7Z6xNrXd2UIeorGj5Ef7b1pJAYB\"\n"
        + "    \"6Y5anaHqZ9J6nKEBvB4DnNLIVWSgARns\"\n"
        + "    \"/8wR2SiRS7MNACwTyrGvt9ts8p12PKFd\"\n"
        + "    \"lqYTopNHR1Vf7XjfhQlVsAJdNiKdYmYV\"\n"
        + "    \"oKlaRv85IfVunYzO0IKXsyl7JCUjCpoG\"\n"
        + "    \"20f0a04COwfneQAGGwd5oa+T8yO5hzuy\"\n" + "    \"Db/XcxxmK01EpqOyuxINew==";
    String keyBytesStr = "tiihtNczf5v6AKRyjwEUhQ==";
    String ivStr = "r7BXXKkLb8qrSNn05n0qiA==";

    byte[] decrypt = s.decrypt(encryptedDataStr, keyBytesStr, ivStr);
    String str;
    try {
      str = new String(decrypt, "utf-8");
      System.out.println(str);
    } catch (UnsupportedEncodingException e) {
      e.printStackTrace();
    }

  }

}