Privacy Policy

Controller and V1 scope

The data controller is the CindrenCalc operator identified in the service details below. Privacy requests can be sent to contact@cindrencalc.com.

CindrenCalc V1 has no user accounts, login, profiles, password database, or account billing.

Data stored in your browser

Cindren Forge, calculation history, and selected larger tools may store projects, preferences, or workspace state in localStorage. History may use sessionStorage as a short-lived fallback. These data stay in the browser until you or the application remove them.

Purposes and data categories

• Serving page and API requests and protecting the service: technical connection and response metadata.
• Handling a voluntary report and any reply: form content, optional email, and limited page context.
• Running a selected remote Cindren Forge operation: the controlled mathematical model needed for the calculation.
• Local calculations, search, and Circuit Analysis Solver run in the browser and do not send their inputs to the backend.

Legal bases

• Minimal security and diagnostic logs used to protect and stabilize the service: the operator's legitimate interests under GDPR Article 6(1)(f).
• Investigation of an actual security incident: the operator's legitimate interests under GDPR Article 6(1)(f).
• Handling voluntary reports, diagnosing and improving the service, and replying to an optional email address: the operator's legitimate interests under GDPR Article 6(1)(f). The field's optional nature is not treated as GDPR consent.
• Ephemeral processing by a remote Cindren Forge function: performance of the function explicitly requested by the user under GDPR Article 6(1)(b).

Feedback form

Voluntarily submitting the form sends the report type and content, an optional email address, and limited page context: interface language, page address, calculator or tool identifier, page type, application version, page title, broad screen-size class, and submission time. The email address is voluntary and is used only to provide a reply.

The report is delivered to a mailbox operated through OVHcloud Zimbra. CindrenCalc stores no form copy in an application database or file. The report is deleted or anonymized no later than 12 months after the matter is closed or resolved if it is no longer needed.

For short-lived abuse prevention, the application keeps an in-memory hash of the connection source with a random per-process salt; this mechanism does not persist the raw IP address.

• The form does not attach the full browser identifier (User-Agent), precise geolocation, advertising identifiers, or device-fingerprinting data.
• Do not include confidential or sensitive information in a submission.

Voluntary support through PayPal

The support page contains only an ordinary external link to PayPal. Before you select it, CindrenCalc does not load PayPal resources or transfer data to PayPal.

After you knowingly select the link, you leave CindrenCalc and any further data processing and payment take place independently on PayPal under its own rules. CindrenCalc does not collect or process card data, payment tokens, or other payment data, and PayPal does not act as CindrenCalc's processor in this link-only flow.

Remote Cindren Forge operations

Most Forge operations run locally. When you choose one of the labelled remote operations and accept the interface notice, the browser may send the validated expression or equation tree, symbols, variables, assumptions, supplied values, and parameters needed for that calculation.

The data are passed to the internal Python/SymPy service and exist in memory only for the execution. They are not written to files, a database, structured logs, error logs, or analytics. Unrelated projects and documents are not included.

Server logs

A minimal access log may contain only timestamp, method, path or route, HTTP status, response time, and client IP according to the trusted-proxy configuration. It is retained for 14 days; ordinary operational-error metadata follows the same limit.

The application does not log request bodies, feedback messages, Forge inputs, Authorization headers, cookies, SMTP credentials, or environment secrets. User-Agent and referrer are not part of the target access-log scope. Additional security-incident logs may be retained for up to 90 days only where needed to investigate an actual incident.

Data recipients

• The CindrenCalc operator as controller.
• The technical server administrator acting only on the operator's instructions as processor under a GDPR Article 28 arrangement; the server is physically located in Poland and CindrenCalc uses no external hosting or data centre. Article 28 is not a separate Article 6 legal basis.
• OVHcloud Zimbra as the email provider for reports and correspondence.

Retention

• Access logs: 14 days.
• Server backups: no more than 30 days; the backup mechanism and enforcement belong to deployment configuration.
• Feedback reports and related correspondence: up to 12 months after closure or resolution, followed by deletion or anonymization if no longer needed.
• Logs for an actual security incident: up to 90 days, only when required for its investigation.
• localStorage and sessionStorage data: until removed by the user, browser, or an application control.

Your rights and complaints

Where applicable under data-protection law, you may request access, rectification, erasure, or restriction and exercise data portability. Send requests to contact@cindrencalc.com.

For processing based on legitimate interests under GDPR Article 6(1)(f), you may object on grounds relating to your particular situation. No account is required; send the objection to contact@cindrencalc.com.

If you believe the processing infringes data-protection law, you have the right to lodge a complaint with the President of the Personal Data Protection Office (Prezes Urzędu Ochrony Danych Osobowych), the competent Polish supervisory authority.

International transfers

Application hosting, technical administration, and the internal Forge service are located in Poland. The mailbox used for feedback forms runs on OVHcloud Zimbra, and OVHcloud states that Zimbra messages are stored in France.

OVHcloud affiliates or subprocessors may participate in providing and maintaining the service under its DPA. This does not mean that data definitely leaves the EEA or that the complete chain always remains exclusively in the EEA. If data are processed outside the EEA, the appropriate safeguards required by law are applied.

Contact and updates

Privacy questions can be sent to the public general-contact address shown below. This policy will be updated if new services or cookies are introduced later.