微信小程序加密数据解密-java

通过 java 实现微信小程序用户加密数据的解密

• 环境：
  window 或 linux
  jdk1.7
• 所需依赖：

<!-- https://mvnrepository.com/artifact/commons-codec/commons-codec -->
    <dependency>
      <groupId>commons-codec</groupId>
      <artifactId>commons-codec</artifactId>
      <version>1.12</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.bouncycastle/bcprov-jdk15on -->
    <dependency>
      <groupId>org.bouncycastle</groupId>
      <artifactId>bcprov-jdk15on</artifactId>
      <version>1.57</version>
    </dependency>

• 代码实现：

package com.test.utils;

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

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.Security;
import java.security.spec.AlgorithmParameterSpec;

public class DecryptionUtils {

    public static String decode(String sessionKey,String encryptedData,String iv)
            throws Exception{
        byte[] encrypData = Base64.decodeBase64(encryptedData);
        byte[] ivData = Base64.decodeBase64(iv);
        byte[] sessionKeyB = Base64.decodeBase64(sessionKey);
        Security.addProvider(new BouncyCastleProvider());
        AlgorithmParameterSpec ivSpec = new IvParameterSpec(ivData);
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding","BC");
        SecretKeySpec keySpec = new SecretKeySpec(sessionKeyB, "AES");
        cipher.init(Cipher.DECRYPT_MODE, keySpec, ivSpec);
        byte[] doFinal = cipher.doFinal(encrypData);
        return new String(doFinal);
    }
}

注意

如果解密报错 javax.crypto.BadPaddingException: pad block corrupted 极有可能是因为sessionKey或encryptedData或iv不匹配