diglabo

Privacy Policy

This Privacy Policy explains how dig hacks, Inc. ("we" or "us") handles personal information in our service.

1. Information We Collect

  • Nickname
  • Birth month and year (e.g., 2008-04; we do not collect the exact day)
  • Authentication information issued by Supabase Auth (identifiers, tokens, and minimal data needed for authentication, such as email address)
  • Technical information (IP address, browser and device info, error logs in minimal scope)
  • If you use the scan grading feature, images of your answer sheets and the results of reading them (see Section 5)
  • Print conditions received through the AI connection (MCP), and a value used to count how many drafts are created (see Section 6)
  • Messages sent through the contact form (email address, name, role, organisation name, and the message itself)
  • Feedback you send (its type, the option you chose on the screen, the page or worksheet concerned, the message, and basic information about your environment; when you report that a problem solved on screen was marked incorrectly, the answer you entered for that problem). We do not ask for an email address or name

2. Purposes of Use

  • Content optimization based on birth month/year to improve user experience
  • Identity verification and authentication using Supabase Auth (login/session management)
  • Account operation (basic settings, support, important notices)
  • Safety and security (fraud prevention, incident response)
  • Legal compliance (fulfilling legal obligations, protecting rights)
  • Service improvement: reviewing feedback and correcting materials and features

3. How We Obtain Information

  • Information users enter and submit (nickname, birth month/year)
  • Identifiers and tokens obtained via Supabase Auth
  • Technical information automatically transmitted during communication

4. Cookies and Similar Technologies

We use only the minimum necessary cookies/storage for authentication and session maintenance (including Supabase Auth). We do not use third-party cookies for behavioral tracking or advertising at this time. We will update this policy if that changes.

5. Scan Grading (Reading Answer Sheets)

The Service includes a feature that photographs the answers you wrote on a printed worksheet and grades them automatically. The following applies only when you use that feature.

  • What we obtain: the photographed image of the answer sheet. After the page is de-skewed in your browser, we store the corrected image in our storage (Cloudflare R2).
  • What we send to an external AI: only the cropped images of the answer boxes, together with formatting hints for each box (expected number of characters, unit symbols, and whether it is a fraction). We do not send the whole page image, the name field image, any information identifying the worksheet, or the correct answers. Boxes are identified by anonymous sequential numbers unrelated to their content.
  • Recipients: we entrust optical character recognition to QwenCloud (Qwen) or Vertex AI (Gemini) on Google Cloud. These services may process data outside Japan. Under the providers’ terms, we do not consent to the use of the data we send for model training.
  • Retention: corrected images are deleted automatically after 90 days. The results of the reading (recognized characters, correct/incorrect marks, timestamp, and which worksheet) are kept until you delete them.
  • Purposes: displaying and keeping a history of grading results, and improving recognition accuracy. Corrections you make to misread values are used to improve accuracy.
  • How to delete: you can delete each grading record individually, or delete them all at once from your dashboard. If you delete your account, all images and reading results are deleted.

6. AI Connection (MCP)

The Service provides an endpoint (an MCP server) that lets your AI client (such as Claude or ChatGPT) create draft kanji and math worksheets. The AI connection requires no login, and we handle information as follows.

  • What we receive: the worksheet conditions your AI sends (kanji, words, format, school grade or Kanken level, title) and which question to replace. For math, we receive the school grade, unit, and search words your AI sends to find problem types, the problem types it selects, the number of problems, the language, and the title. We do not ask for information that identifies you, such as your name or email address. We do not receive your conversation with the AI or information stored in your AI client.
  • What we store: the conditions and the selected questions (a "draft"), and a value used to count how many drafts can be created per day (a one-way transformation of the IP address; the IP address itself is not stored). Answers are not stored.
  • Where and how long: stored in Supabase (Tokyo region). A draft stops working 30 days after it is created and is then deleted automatically.
  • Purposes: showing the draft through its review link, and preventing abuse (limiting how many drafts can be created).
  • Who can see it: anyone who has the review link can open the draft and save it as their own worksheet until it expires. Please be careful about whom you share the link with.
  • Saved worksheets: a worksheet saved on the linked page is handled in the same way as any other worksheet.
  • Feedback: your AI client may send a report about an error in the result of a tool or a suggestion for improvement. We receive only the content of the report (its type, severity and summary, the tool or draft concerned, the input given to the tool, the expected and actual results, and the names of the AI client and model), not your conversation. Storage and retention are the same as for feedback in Section 10.
  • Learning summary links: from the learning records screen, a parent can turn their child's math learning summary (school grade, the problem types the child still gets wrong or has overcome, the problems answered incorrectly with the child's answers, progress by unit, and the list of sessions) into a link. It does not include the child's name or date of birth. Anyone who has the link, and any AI given the link, can read the summary for 7 days after it is created. The parent can revoke it at any time, after which it can no longer be read. Summaries are stored in Supabase (Tokyo region) and deleted automatically after they expire.
  • Deletion: drafts are deleted automatically when they expire. To request deletion before then, contact us at the address in Section 16 with the link.

Photo-based kanji worksheets (pilot)

We send only the cropped, resized image selected by you to the QwenCloud (Qwen) or Google Cloud (Gemini) service shown on the screen to identify learning characters and words. Our servers, history and logs do not retain the original or submitted image. Retention by the AI provider depends on its service, API and settings.

Extracted characters and words are temporarily kept in this tab for review and returning after sign-in. Confirmed proposals follow section 6; their shared links do not contain photos. Usage limits use identifiers hashed with a secret. Daily registered-user counts are deleted after 90 days; trial-used counts are retained to prevent repeated trials; monthly budget counts are deleted after 13 months.

7. Sharing with Third Parties

We do not provide personal information to third parties without your consent, except as required by law, to protect life or property, or when necessary to achieve the purposes described above through service providers.

8. Entrusted Processing and Joint Use

  • We entrust authentication functions to Supabase (Supabase Inc.). Our processors implement appropriate security measures under our control. For Supabase privacy information, seehere.
  • We entrust the storage of answer sheet images to Cloudflare (Cloudflare, Inc.) and the character recognition of answer boxes to Google Cloud (Google LLC). See their privacy information atCloudflare and Google.
  • We entrust the sending of emails related to contact form enquiries to Resend (Resend, Inc.). For Resend privacy information, see here.
  • We do not conduct joint use at this time. If started, we will disclose scope, items, and controller.

9. International Transfers

Supabase servers are located in the Tokyo region (Japan). By contrast, Cloudflare, which stores answer sheet images, and Google Cloud, which performs character recognition, may process data outside your country (for example, in the United States). In every case we handle data with appropriate safeguards in accordance with applicable laws.

Resend, which we use to send contact form emails, may also process data outside Japan (for example in the United States).

10. Retention

We retain information for as long as necessary to fulfill the purposes and delete or anonymize it when no longer needed. When you delete your account, we delete related data except where retention is required by law.

Images of answer sheets stored by scan grading are deleted automatically after 90 days, as described in Section 5.

Contact form enquiries are deleted automatically one year after receipt, and feedback two years after receipt. To count the number of submissions, we store a value derived from the IP address in a form that cannot be reversed (the IP address itself is not stored).

11. Security Measures

We implement technical and organizational measures such as access control, least-privilege design, encryption in transit, and logging. We limit the data collected to the minimum necessary (e.g., birth is stored as year-month only).

12. Your Rights

You may request disclosure, correction, suspension of use, or deletion of your personal information. Please contact us at the address below. We will respond within a reasonable scope unless otherwise required by law.

13. Minors

Minors should use the service with the consent of a guardian.

14. Compliance

We comply with applicable privacy laws and guidelines. Where regional laws (e.g., GDPR) apply, we handle data in accordance with those laws to the extent applicable.

15. Changes to This Policy

We may update this Policy due to legal changes or service updates. For material changes, we will notify you in the service. The latest version will apply after updates.

16. Company and Contact

17. Effective Date and Last Updated

Effective: 2025-10-16 / Last Updated: 2026-10-13