.NET Core 对接微信小程序数据解密

/// <summary>
/// 解密微信数据
/// </summary>
/// <param name="encryptedData">加密的数据</param>
/// <param name="encryptIv">iv向量</param>
/// <param name="sessionKey">调用 wx auth.code2Session 来获得</param>
/// <returns></returns>
public static string WechatDecrypt(string encryptedData, string encryptIv, string sessionKey)
{
    //base64解码为字节数组
    var encryptData = Convert.FromBase64String(encryptedData);
    var key = Convert.FromBase64String(sessionKey);
    var iv = Convert.FromBase64String(encryptIv);

    //创建aes对象
    var aes = Aes.Create();

    if (aes == null)
    {
        throw new InvalidOperationException("未能获取Aes算法实例");
    }
    //设置模式为CBC
    aes.Mode = CipherMode.CBC;
    //设置Key大小
    aes.KeySize = 128;
    //设置填充
    aes.Padding = PaddingMode.PKCS7;
    aes.Key = key;
    aes.IV = iv;

    //创建解密器
    var de = aes.CreateDecryptor();
    //解密数据
    var decodeByteData = de.TransformFinalBlock(encryptData, 0, encryptData.Length);
    //转换为字符串
    var data = Encoding.UTF8.GetString(decodeByteData);

    return data;
}