# Demo how to distribute web application with encrypted data
**URL:** https://forum.castle-engine.io/t/demo-how-to-distribute-web-application-with-encrypted-data/2039
**Category:** News
**Created:** [October 18, 2025, 10:07pm UTC](https://forum.castle-engine.io/t/demo-how-to-distribute-web-application-with-encrypted-data/2039 "2025-10-18T22:07:06Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@michalis](https://forum.castle-engine.io/u/michalis)
#### Post date: [October 18, 2025, 10:07pm UTC](https://forum.castle-engine.io/t/demo-how-to-distribute-web-application-with-encrypted-data/2039/1 "2025-10-18T22:07:06Z")
| [](https://castle-engine.io/wp/wp-content/uploads/2025/10/Zrzut-ekranu-z-2025-10-18-20-35-22.png "Web application with encrypted data") |
We present a demo showing how you can keep your web application data encrypted (with decryption key embedded in your application code).
By default, when you build a [web application](https://castle-engine.io/web), the data is packed into a ZIP file, and a person that wants to access your data can download this ZIP and unpack the data on their own system (and e.g. extract your 3D models or textures).
The demo on [demo\_encrypt\_decrypt\_data](https://github.com/castle-engine/demo_encrypt_decrypt_data) shows how to prevent this. The data gets encrypted using `BlowFish` with your password, and then it is decrypted as you access it from your WebAssembly application. Read the `README.md` instructions in the demo for
- how to build it,
- how it works,
- how to adopt it to your own applications,
- and, to be clear and explicit, what are the limitations of this approach. It’s not a fool-proof solution to keep your data secret from a dedicated attacker, and there’s no such solution (in any game engine).
The [README in the demo\_encrypt\_decrypt\_data project](https://github.com/castle-engine/demo_encrypt_decrypt_data) already explains all the details, so if this sounds interesting, please read it 🙂
_Big thank you go to [UND DREAM Lab](https://dream.crc.und.edu/) for sponsoring this demo through Patreon! Your [donations to Castle Game Engine](https://castle-engine.io/donate) make our engine sustainable._
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### Author:  [@michalis](https://forum.castle-engine.io/u/michalis)
#### Post date: [October 18, 2025, 10:15pm UTC](https://forum.castle-engine.io/t/demo-how-to-distribute-web-application-with-encrypted-data/2039/2 "2025-10-18T22:15:53Z")