Privacy Policy
Last updated: June 10, 2026
Kyoto Makotoya ("we," "us," or "our") operates the Seal mobile application (the "App"). This page informs you of our policies regarding the collection, use, and disclosure of personal information when you use the App.
Information We Do Not Collect
Seal is designed with privacy as a core principle. The App does not collect, store, or transmit:
- Your name, email address, or any personally identifiable information
- Your NFC tag contents in plain text
- Decryption keys (keys are generated on your device and never leave it)
- Device identifiers for tracking purposes
- Browsing history or usage analytics
How the App Works
When you write a Contact or Message to your Grain Patch:
- Your information is encrypted on your device using AES-256-GCM encryption before anything is sent.
- Only the encrypted data (ciphertext, initialization vector, authentication tag, schema version, and algorithm identifier) is stored on our server.
- The decryption key is embedded only in the NFC tag URL fragment (
#k=) and is never transmitted to or stored on our server. - No one — including Kyoto Makotoya — can read the contents of your Grain Patch without physical access to the tag.
For Link and Location categories, data is written directly to the NFC tag and is not sent to our server.
Location Data
The App requests access to your location only when you choose to write your current location to a Grain Patch. Location data is used solely to generate a maps link and is not stored or transmitted beyond that action.
NFC Usage
The App uses your device’s NFC capability to write information to Grain Patch tags. NFC is used solely for this writing function and is not used to read data from other tags or devices.
Third-Party Services
The App does not use third-party analytics, advertising SDKs, or tracking services.
Data Retention
Encrypted data stored on our server can be deleted at any time by the tag owner using the delete function within the App. Upon deletion, all associated data is permanently removed from our servers.
Children’s Privacy
The App does not knowingly collect information from children under 13. The App is rated 4+ and contains no age-restricted content.
Changes to This Policy
We may update this Privacy Policy from time to time. Any changes will be posted on this page with an updated date.
Contact Us
If you have any questions about this Privacy Policy, please contact us:
Kyoto Makotoya
Email: info@kyoto-makotoya.com
Website: https://kyoto-makotoya.com