OpenTimestamps

Sections

Use this page as a guide: start with the proof model, then look at where it helps, what to compare it against, and its limits.

Plain termsHashing, proofs, and Bitcoin anchoring. Where it helpsIntegrity and proof-of-existence cases. Compare againstCheck the centralised timestamp alternatives. LimitsWhat the proof shows and what remains outside scope.

In plain terms

The important idea is simple: hash the data, create a proof, and later verify that the proof was anchored before a time. [R1][R2]

Core mechanism

The file is hashed locally before upload. [R2]
The hash is used as the basis for the timestamp proof. [R1][R2]
Proofs can be aggregated before they are anchored. [R3]
Bitcoin provides the public anchoring layer. [R1][R3]

What verification shows

That the data existed before a particular time. [R1]
That the proof chain is still valid. [R2]
That the proof matches the original data hash. [R2]
That no trust in a single timestamp server is required later. [R3]

Where it helps

OpenTimestamps is useful wherever integrity, ordering, or later proof of existence matters more than a central timestamping service. [R1]

Document integrity

Prove that a file existed before a dispute, release, or audit. [R2]

Public records

Timestamp reports, disclosures, or evidence without a single keeper. [R3]

Software supply chains

Timestamp build artifacts or release hashes for later checking. [R2]

Research and publishing

Mark a result, draft, or submission before publication. [R2]

Compare against

The comparison is usually with central timestamping services or ordinary signed documents.

Conventional timestamping

Central services can be simpler to use. [R1]
They also require trust in the service operator. [R1]
OpenTimestamps is useful when independent verification matters more than simplicity. [R1]

Ordinary signed documents

Digital signatures can show who signed a document, while timing can remain less clear. [R1]
OpenTimestamps adds a time-linked proof without changing the underlying document. [R2]
That makes it a narrow complement rather than a general replacement. [R1]

Limits and trade-offs

What critics are right about

Authorship remains a separate question. [R1]
Truth and correctness still need separate evidence. [R1]
Private handling remains outside the proof itself. [R1]
Legal evidence rules still apply on top. [R1]

Boundaries

You still need a verifier and a proof file. [R2]
Availability depends on the tooling you keep around. [R3]
Anchoring frequency affects finality timing. [R3]
It is an integrity tool rather than a general storage system. [R1]

Primary sources

Documentation

Sources

References

[R1] OpenTimestamps website: opentimestamps.org
[R2] OpenTimestamps client repository: github.com/opentimestamps/opentimestamps-client
[R3] OpenTimestamps server repository: github.com/opentimestamps/opentimestamps-server