How to prove code existed at a specific timeGit dates can be rewritten; date a fingerprint of the exact tree or archive

TimeBinder adds a layer of protection against AI and human fraud and disputes.

The file stays on your device. Your browser makes a digital fingerprint of the file. TimeBinder records the fingerprint and the time, not the file.

Short answer

Git commit dates can be rewritten or set when you commit, so they are not independent proof. A stronger record is a dated fingerprint of the exact tree, archive or release file. That shows those bytes existed no later than the recorded time and still match. It does not prove you wrote the code.

What git dates show, and where they fall short

A git commit carries an author date and a committer date. They are part of a useful history, especially on a shared remote. They are also fields you can set, and a rewritten history can change them. Signed commits and tags help show which key signed a commit; they still do not, on their own, fix a date you control. See git commit dates as proof and the longer guide prove source code existed before a date.

A dated fingerprint answers a narrower question: did this exact tree, zip, tarball or release file exist by this time? Make an archive of the commit or release you care about, compute its SHA-256 hash, and record that hash with a time you do not control. A TimeBind does this in the browser; the file is not uploaded; the record is anchored to Bitcoin. First Pooled TimeBind free, then from US$5; ASAP is US$15. You can also place a copy in a public archive; see Zenodo and Software Heritage versus a timestamp and source code timestamping.

What to date, and what a match shows

Date the snapshot you may need to show — a tagged release, a zip of the repo at a milestone, or the exact file you delivered. If you keep working, later commits are different bytes and need their own record if they matter. To check a file you still hold, use the SHA-256 file hash checker. A matching TimeBind shows that those exact bytes existed no later than the recorded time. It does not show you wrote the code, that it compiles, or that you own it.

Make a TimeBind: first one free →

First Pooled TimeBind free, no card, then from US$5. An ASAP TimeBind is US$15.

Frequently asked questions

Can git commit dates be faked?

They can be set when you commit and can change if history is rewritten. Treat them as a useful log, not as an independent clock. A dated fingerprint of an archive of that commit is harder to alter quietly.

Should I timestamp every commit?

Usually no. Date the milestones you might need to show: a release, a delivery, or a version you disclosed. You can date more often if a dispute is already likely.

Does a GitHub or GitLab timestamp count?

A push visible on a host you do not control can be supporting evidence. It still depends on that host’s logs. A hash timestamp you can check independently is a separate record of the same bytes.

Does a TimeBind prove I am the author of the code?

No. It shows that this exact file existed no later than the recorded time and still matches. It does not show who wrote the code or who owns it.

Sources

Git documentation, git-commit (author and committer dates can be set) and git-rebase (history can be rewritten).
TimeBinder, Prove source code existed before a date and git commit dates as proof.

Related guides and tools

Your file’s fingerprint, anchored to a global network secured by real electricity and cryptography.

Editing a file—including with AI—changes its fingerprint, not its existing network record.

How this works

Your file’s SHA-256 fingerprint, a short code worked out from its exact contents, is made in your browser, and the file itself stays on your device. A cryptographic commitment to that fingerprint, which may be combined with others, is then anchored in a block on the Bitcoin blockchain. Bitcoin is secured by proof of work: computers around the world spend real electricity to add each block, and changing an earlier block would mean redoing that work faster than the rest of the network. Until that block is confirmed, your proof is pending. Once the Bitcoin anchoring is confirmed, you can verify the proof against that recorded commitment. The confirmed record can then be checked; Pooled TimeBinds are checked through TimeBinder, while ASAP TimeBinds can also be checked independently. If you check the file later and its fingerprint still matches, that shows the file existed no later than the recorded time. The record doesn’t show who made the file, whether AI was used, or that its contents are true.

Your filestays on your device
FingerprintSHA-256
Network timestampon Bitcoin

Record a fingerprint of the file you rely on

Add a layer of protection against AI and human fraud and disputes: a dated, checkable record of the exact file you hold.

Open the app and sign in with email or Google.
Add your files. They stay on your computer.
Seal them and download your Proof of Time certificates.

Open TimeBinder →

First Pooled TimeBind free, no card, then from US$5. See pricing.