Privacy Policy
Last updated: 31 October 2026. This policy describes what Project Cherenkov ("we") does with personal data. It was drafted by the project team, is not legal advice, and should be reviewed by a qualified lawyer before launch. An Indonesian version is published on the site at /id/privacy; if the two differ, please tell us.
1. Who is responsible
Project Cherenkov is a student-run project. The person responsible for your data is the project owner, reachable at projectcherenkov@gmail.com.
2. What we collect
Without an account we collect nothing about you beyond ordinary server logs kept by our hosting provider. The study timer, the "try it first" preference and site search run in your browser and are not sent to us.
With an account we store your email address, your sign-in credentials (passwords are stored hashed; if you use Google sign-in we receive your Google account email and name), and the study data you create: quiz answers and retries, study sessions (when, how long, subject), pages you marked as understood, and planner settings and self-ratings. You can see this on your Progress and Missed questions pages and delete individual study sessions there.
3. The Neutrino chat companion (third-party AI)
If you use the Neutrino chat, the messages you type, and the context needed to answer them, are sent to Google's Gemini API to generate a reply. Google processes this data under its own terms and privacy policy and may retain it for a limited period. Do not enter personal information, passwords, or anything you would not want a third-party service to see. If you provide your own Google API key, requests are made with that key under your own agreement with Google. We do not use chat messages for advertising.
4. Why we use it (legal basis)
We use your data to provide the account, quiz and planner features you ask for (performance of the service you request), to keep the site secure, and to answer your messages. For Neutrino chat and any optional features we rely on your consent, which you can withdraw by not using the feature or by deleting your account.
5. Who receives it
Service providers that run the site for us: hosting (currently Vercel), the database (currently Neon), Google (sign-in and the Neutrino chat), and our email provider if email is enabled. They process data only to provide those services. We do not sell personal data.
6. Where it is processed
These providers may process data outside Indonesia, including in the United States and Europe. By using the account and chat features you understand your data may be transferred there.
7. How long we keep it
Account and study data are kept until you delete your account or ask us to delete it. Server logs are kept by the hosting provider for its standard period. Chat messages are not stored by us beyond the conversation in your browser; Google's retention is set by Google.
8. Your rights
Under Indonesian Law No. 27 of 2022 on Personal Data Protection you may ask to access, correct, delete or restrict the use of your personal data, to withdraw consent, and to receive a copy of data you provided. Email us and we will respond within a reasonable time. If you are in another jurisdiction, you may have additional rights.
9. Children and teenagers
Some features are aimed at secondary-school students. If you are under 18, please use an account and the Neutrino chat only with the knowledge and permission of a parent or guardian. We do not knowingly collect more data than the features above require, and we will delete a child's data on a parent's or guardian's request.
<!-- OWNER DECISION: Google's Gemini API terms restrict use in services likely to be accessed by under-18s, and Indonesia's PP 17/2025 (PP Tunas) sets duties for services children may use. Decide whether Neutrino is limited to adults or replaced before launch, then update this section. -->10. Cookies
We use only the cookies needed to keep you signed in and to remember your language and theme. We do not run advertising or tracking cookies. If analytics are added, we will update this page first.
11. Security and incidents
We use access controls, hashed passwords and encrypted connections. If a personal-data breach affects you, we will notify you and the relevant authority as the law requires.
12. Changes
We will change this policy when our practices change and show the new date at the top. For changes that matter (for example a new third-party recipient), we will tell signed-in users before they take effect rather than treating continued use as agreement.
13. Contact
Project email: projectcherenkov@gmail.com