Free
$0
- Seal files or folders in your browser
- Bitcoin record and two signed timestamps
- Public receipt and printable certificate
- Reveal files whenever you choose
- No account: the record holds no name, email or address
pith seal
Seal now. Keep it private. Prove later.
A seal proves that a manuscript, a dataset or a code repository existed at a moment, without anyone seeing it. When you're ready, you reveal the files you choose, and the date comes with them.
An example
Maya finishes a manuscript in March. She isn't ready to post it; the proofs need another month. She drops the PDF onto the seal page. The file never leaves her laptop: Pith receives one number, records it in Bitcoin and gets two signed timestamps. Maya keeps the small seal file the page gives her next to the PDF.
In May a preprint with a similar result appears. Maya posts her paper and reveals the sealed PDF on the seal's public receipt. Anyone can now check, with Pith or without it, that this exact file existed in March.
How it works
- Fingerprint. Your browser fingerprints every file and mixes in a secret random number. Only one combined number leaves your computer.
- Anchor. Pith records that number in the Bitcoin blockchain and gets signed timestamps from DigiCert and FreeTSA.
- Reveal. When you choose, reveal any file on the seal's public receipt. Anyone holding the file can check its date. The files you don't reveal stay hidden.
What a seal proves, and what it doesn't
A seal proves that these exact files existed no later than the recorded time. Change one character and a file no longer matches. Pith can't backdate a seal either: the Bitcoin record and the authorities' signatures are outside its control, and standard tools check them.
It doesn't prove who wrote the files or whether they're right. And proving a file existed is not the same as proving you committed to it. Someone could seal several opposite predictions and reveal only the one that came true. For dating a paper, that doesn't matter. For a prediction or a preregistration, it does.
Predictions and preregistration
A commitment is a seal that others knew about before the outcome, and that you then reveal in full:
- Name the seal publicly before the outcome. Put its id in a record that exists once for the study, such as its trial registry entry, its ethics approval or a registered-report protocol. The content stays private; the fact that a sealed plan exists is public. Another account or another seal can't take the place of the one that record names.
- Reveal every file. Once every file in the seal is revealed, its receipt says so. Nothing sealed alongside the plan can stay hidden.
For example: seal the analysis plan before data collection, enter the seal id in the trial registry, and reveal the plan with the paper. Readers can check that the plan came before the data.
Plans
Seal Pro
$10 a month
- Everything in Free
- Seal from the command line, or on every push
- A private history of every seal, with your labels
- On reveal, the receipt can show which verified account made the seal (not who wrote the work)
- Permanent encrypted copies included, 50 MB a month
Institutions
Talk to us
- Seal Pro for your members, billed once
- Help fitting Seal into your group's workflow
When you need more
- Timed release: lock sealed files until a date you choose, after which they open by themselves.
- Permanent copies: keep an encrypted copy on Arweave that 24 recovery words, or two of three trusted people, can open if you lose everything.
- Command line, CI and API: seal every version of a repository automatically.
Questions
Can Pith see my files?
No. Pith receives one number made from salted fingerprints. It can't tell a seal of one sentence from a seal of a whole repository, and it never receives the salts.
What if Pith shuts down?
Your seals still prove what they prove. The Bitcoin proof and the timestamp tokens are standard files, downloadable from every receipt and kept in your seal file, and open tools check them without Pith.
What if I lose my seal file?
It holds the random numbers that tie your files to the seal, so keep it with the files. A permanent copy brings back both if you lose everything.
Is a seal a patent?
No. It is dated evidence that specific files existed, and it discloses nothing about their content. If you plan to patent an invention, talk to counsel before you publish it.