public static byte[] Decode(byte[] data, string key, string extension = "")
    {
        string @string = Encoding.UTF8.GetString(data, 0, 4);
        if (@string != ResourceFileElement.SIGNATURE)
        {
            Debug.LogError("not .fe");
            return null;
        }
        int num = (int)BitConverter.ToInt16(data, 12);
        int num2 = (int)BitConverter.ToInt16(data, 14);
        byte[] array = new byte[16];
        Array.Copy(data, 16, array, 0, 16);
        byte[] array2 = new byte[16];
        Array.Copy(data, 32, array2, 0, 16);
        int size = data.Length - 48;
        byte[] array3 = ResourceFileElement.DecodeAES(data, 48, size, array2, Encoding.UTF8.GetBytes(key));
        if (num2 > 0)
        {
            Array.Resize<byte>(ref array3, array3.Length - num2);
        }
        if (num == 1)
        {
            array3 = ResourceFileElement.DecompressGZip(array3);
        }
        byte[] data2 = null;
        using (MD5CryptoServiceProvider mD5CryptoServiceProvider = new MD5CryptoServiceProvider())
        {
            data2 = mD5CryptoServiceProvider.ComputeHash(array3);
        }
        if (Utility.Bin2Hex(array, -1) != Utility.Bin2Hex(data2, -1))
        {
            Debug.LogError("md5 check error.");
            return null;
        }
        string text = string.Empty;
        bool flag = false;
        switch (extension)
        {
        case ".unity3d":
            text = Encoding.UTF8.GetString(array3, 0, 8);
            if (text != "UnityWeb" && text != "UnityRaw")
            {
                flag = true;
            }
            break;
        case ".jpg":
            text = BitConverter.ToString(array3, 0, 2);
            if (text != "FF-D8")
            {
                flag = true;
            }
            break;
        case ".png":
            text = BitConverter.ToString(array3, 0, 4);
            if (text != "89-50-4E-47")
            {
                flag = true;
            }
            break;
        case ".acb":
        case ".acf":
            text = Encoding.UTF8.GetString(array3, 0, 4);
            if (text != "@UTF")
            {
                flag = true;
            }
            break;
        }
        if (flag)
        {
            Debug.LogError("signature = " + text + " error.");
            return null;
        }
        return array3;
    }

    public static byte[] DecompressGZip(byte[] data)
    {
        byte[] array = new byte[32768];
        MemoryStream memoryStream = new MemoryStream(data, 0, data.Length);
        MemoryStream memoryStream2 = new MemoryStream();
        GZipStream gZipStream = new GZipStream(memoryStream, CompressionMode.Decompress);
        int count;
        while ((count = gZipStream.Read(array, 0, array.Length)) > 0)
        {
            memoryStream2.Write(array, 0, count);
        }
        byte[] result = memoryStream2.ToArray();
        memoryStream2.Close();
        gZipStream.Close();
        memoryStream.Close();
        return result;
    }
    public static byte[] DecodeAES(byte[] data, int seek, int size, byte[] iv, byte[] key)
    {
        AesManaged aesManaged = new AesManaged();
        aesManaged.BlockSize = 128;
        aesManaged.KeySize = 128;
        aesManaged.Mode = CipherMode.CBC;
        aesManaged.Padding = PaddingMode.Zeros;
        aesManaged.IV = iv;
        aesManaged.Key = key;
        byte[] result = null;
        using (MemoryStream memoryStream = new MemoryStream(data, seek, size, false, true))
        {
            using (CryptoStream cryptoStream = new CryptoStream(memoryStream, aesManaged.CreateDecryptor(), CryptoStreamMode.Read))
            {
                using (MemoryStream memoryStream2 = new MemoryStream())
                {
                    byte[] array = new byte[32768];
                    while (true)
                    {
                        int num = cryptoStream.Read(array, 0, array.Length);
                        if (num <= 0)
                        {
                            break;
                        }
                        memoryStream2.Write(array, 0, num);
                    }
                    result = memoryStream2.ToArray();
                }
            }
        }
        return result;
    }