java实现微信小程序加密数据解密算法

<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>

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;

  }

}

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;

  }

}

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));

  }

}