Svartnod is a free browser-based tool for creating and verifying proof-of-existence timestamps anchored to Bitcoin through OpenTimestamps.
Website:
https://svartnod.comSwedish version:
https://svartnod.seBrowser client source:
https://github.com/swedoc/svartnod-clientHow it worksThe selected file is read and hashed locally in the browser. The original file never leaves the user's device.
The browser then creates a nonce-protected commitment. Only that blinded commitment is sent through the Svartnod relay to public OpenTimestamps calendars.
The resulting proof can later be upgraded and verified against Bitcoin block data retrieved through my own Bitcoin full node.
What I wanted to add on top of OpenTimestamps- A simple web interface for people who do not use command-line tools
- Local file hashing in the browser
- A blinded commitment instead of exposing the raw file hash to the server
- Verification through my own Bitcoin node rather than a third-party block explorer
- Support for Swedish, English, Spanish, French, Korean and Chinese
- No accounts, document storage, token or payment system
What it provesA valid upgraded proof shows that the exact file content existed no later than the Bitcoin block containing the timestamp commitment.
It does not by itself prove authorship, ownership or that the document contents are true. For authorship claims, the file should first be digitally signed and then timestamped.
Source code and scopeThe published repository contains the exact browser-side client files currently used in production, together with SHA-256 checksums and the retained license for the vendored noble-hashes code.
The relay server, Bitcoin node adapter, deployment configuration and private metrics are not currently included in the public repository.
InfrastructureThe service runs on a Raspberry Pi 5 connected to my own Bitcoin full node. The goal was to build and operate the entire chain myself, from the browser client to final Bitcoin verification.
This is not a new timestamp protocol. It is a privacy-focused and accessible interface built on OpenTimestamps.
Technical criticism and review of the trust model, nonce blinding and verification design are welcome.
