微信小程序的加密与解密--java

　　可能是微信认为java 对称加密算法做的比较好。没有给出java的例子。

微信签名加密：利用最简单的AES加密方式

关键代码：

public static String encode(String str) {
        if (str == null) {
            return null;
        }
        try {
            MessageDigest messageDigest = MessageDigest.getInstance("SHA1");
            messageDigest.update(str.getBytes("UTF-8"));
            return getFormattedText(messageDigest.digest());
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

　　微信解密方式：

　　　　需要密钥，需要偏移量

关键代码：

/**
     * AES解密
     *
     * @param content 密文
     * @return
     * @throws InvalidAlgorithmParameterException
     * @throws NoSuchProviderException
     */
    public static byte[] decrypt(byte[] content, byte[] keyByte, byte[] ivByte) throws InvalidAlgorithmParameterException {
        try {
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
            SecretKeySpec sKeySpec = new SecretKeySpec(keyByte, "AES");
            cipher.init(Cipher.DECRYPT_MODE, sKeySpec, generateIV(ivByte));
            byte[] result = cipher.doFinal(content);
            return result;
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }

整个类：

package com.paic.aims.common.util;


import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.AlgorithmParameters;
import java.security.InvalidAlgorithmParameterException;
import java.security.MessageDigest;
import java.security.NoSuchProviderException;

/**
 * @author zhongzheng664
 * @date 2018/9/26.
 */
public class Sha1Utils {
    private static final char[] HEX_DIGITS = {'0', '1', '2', '3', '4', '5', '6',
            '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};

    /**
     * 把密文转换成十六进制的字符串形式
     * @param bytes
     * @return  十六进制的字符串
     */
    private static String getFormattedText(byte[] bytes) {
        int len = bytes.length;
        StringBuilder buf = new StringBuilder(len * 2);
        // 把密文转换成十六进制的字符串形式
        for (int j = 0; j < len; j++) {
            buf.append(HEX_DIGITS[(bytes[j] >> 4) & 0x0f]);
            buf.append(HEX_DIGITS[bytes[j] & 0x0f]);
        }
        return buf.toString();
    }

    public static String encode(String str) {
        if (str == null) {
            return null;
        }
        try {
            MessageDigest messageDigest = MessageDigest.getInstance("SHA1");
            messageDigest.update(str.getBytes("UTF-8"));
            return getFormattedText(messageDigest.digest());
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * AES解密
     *
     * @param content 密文
     * @return
     * @throws InvalidAlgorithmParameterException
     * @throws NoSuchProviderException
     */
    public static byte[] decrypt(byte[] content, byte[] keyByte, byte[] ivByte) throws InvalidAlgorithmParameterException {
        try {
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
            SecretKeySpec sKeySpec = new SecretKeySpec(keyByte, "AES");
            cipher.init(Cipher.DECRYPT_MODE, sKeySpec, generateIV(ivByte));
            byte[] result = cipher.doFinal(content);
            return result;
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }


    // 生成iv
    public static AlgorithmParameters generateIV(byte[] iv) throws Exception {
        AlgorithmParameters params = AlgorithmParameters.getInstance("AES");
        params.init(new IvParameterSpec(iv));
        return params;
    }


    public static void main(String[] agrs) {
        String str = "{\"nickName\":\"Band\",\"gender\":1,\"language\":\"zh_CN\",\"city\":\"Guangzhou\",\"province\":\"Guangdong\",\"country\":\"CN\",\"avatarUrl\":\"http://wx.qlogo.cn/mmopen/vi_32/1vZvI39NWFQ9XM4LtQpFrQJ1xlgZxx3w7bQxKARol6503Iuswjjn6nIGBiaycAjAtpujxyzYsrztuuICqIM5ibXQ/0\"}HyVFkGl5F5OQWJZZaNzBBg==";
        //微信加密
        String encode = encode(str);
        String session_key = "HyVFkGl5F5OQWJZZaNzBBg==";
        String appId = "wx4f4bc4dec97d474b";
        String encryptedData = "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";
        String sessionKey = "tiihtNczf5v6AKRyjwEUhQ==";
        String iv = "r7BXXKkLb8qrSNn05n0qiA==";
        System.out.println(encode);
        try {
            byte[] resultByte=decrypt(Base64.decodeBase64(encryptedData),Base64.decodeBase64(sessionKey),
                    Base64.decodeBase64(iv));
            String jsonStr=new String(resultByte, "utf-8");
            //字符串转json
            JSONObject jsonObject= JSON.parseObject(jsonStr);
            System.out.println(new String(resultByte, "utf-8"));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}