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27. 09. 2026 Where does my money go? This is the question everyone asks themselves when they look at a bank statement and wonder when they even spent that much. Vadnica-bank is an open-source web application for recording banking transactions, built on the zero-knowledge principle — your financial data is encrypted in the browser before it ever reaches the server.
What is Vadnica-bank?
Vadnica-bank is a simple banking transaction diary — the one you may have wanted to build in Excel but never got around to. It lets you record income and expenses, categorize them, and keep an overview of your balance — without registering with a third party that would store your data in plain text.
- Recording transactions (income and expenses)
- Zero knowledge — data is encrypted with AES256 in the browser
- The master password is never stored in readable form
- Bilingual interface (Slovenian and English)
How Zero Knowledge Works
When you enter a transaction, the AES256 algorithm encrypts it in the browser immediately. The encryption key is derived from your master password, so only your computer knows it — it never reaches the server. The server therefore receives only encrypted data that cannot be read without your password, not even by the administrator.
user → transaction entry
↓
AES256 encryption in the browser
↓
server receives only encrypted data
↓
without the master password, the data is unreadable
Open Source
The entire code is publicly available on GitHub, which means anyone can inspect it, verify it, and even run the application on their own server. Trust in security solutions is built through transparency, not promises.
| Feature | Vadnica-bank | Typical application |
|---|---|---|
| Data encryption | AES256 in the browser | Depends on the provider |
| Server access to data | No (zero-knowledge) | Often yes |
| Source code | Public (GitHub) | Closed |
Links
Web application: bank.vadnica.org. Source code: github.com/vadnica/vadnica-bank. This project is part of the Vadnica ecosystem, where I would like to add as many useful everyday applications as possible. This is my hobby project — my original education is not in programming, so I also rely on AI for help, mainly with translation and writing text, which I of course review myself afterwards.