微信支付平台证书返回解密方法封装

废话不多说，直接上代码：

package com.isuidian.util;

import java.io.IOException;
import java.security.*;
import java.util.Base64;

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

public class WechatStaticUtil {

    private static final int KEY_LENGTH_BYTE = 32;
    private static final int TAG_LENGTH_BIT = 128;

    public static String decryptToString(byte[] apiV3Key, byte[] associatedData, byte[] nonce, String ciphertext) throws GeneralSecurityException, IOException {

        if (apiV3Key.length != KEY_LENGTH_BYTE) {
            throw new IllegalArgumentException("无效的ApiV3Key，长度必须为32个字节");
        }

        try {
            Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");

            SecretKeySpec key = new SecretKeySpec(apiV3Key, "AES");
            GCMParameterSpec spec = new GCMParameterSpec(TAG_LENGTH_BIT, nonce);
            cipher.init(Cipher.DECRYPT_MODE, key, spec);
            cipher.updateAAD(associatedData);

            return new String(cipher.doFinal(Base64.getDecoder().decode(ciphertext)), "utf-8");
        } catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
            throw new IllegalStateException(e);
        } catch (InvalidKeyException | InvalidAlgorithmParameterException e) {
            throw new IllegalArgumentException(e);
        }
    }

}