OpenTimestamps
A scheme that anchors a hash into the Bitcoin blockchain so a document can be proved to have existed at a time. It proves existence and integrity; it proves nothing about whether the content was correct.
Glossary · area 8 of 19
Proof and provenance
Showing a record existed at a date without asking anyone to trust us.
13 terms. Each opens its own page with what it can and cannot support, how the scanner measures it, and where it comes up in the guides.
13terms in this area
0with a live finding rate
anchoring
Committing a hash to a public ledger so it cannot be backdated. Useful for a report whose value depends on the date it was taken.
Content hash
A deterministic digest of a payload. Two parties can confirm they read identical bytes by comparing one short string instead of the whole document.
Manifest tampering
Editing a change log or metadata record after the fact. Hash-chained records make it detectable: the edit no longer matches the digest that was sealed at the time.
C2PA
The Coalition for Content Provenance and Authenticity specification: a signed manifest bound to an image, video or audio file recording how it was created and what was done to it, often surfaced as Content Credentials. It establishes provenance, the chain of edits, and nothing about rights: a manifest does not prove copyright ownership, and an asset with no manifest is not thereby unowned or synthetic. Most assets on the web carry none, so absence is the ordinary case, not a finding.
CAWG training and data mining assertion
An assertion from the Creator Assertions Working Group that travels inside a C2PA manifest and states the creator's preference about AI training and data mining for that specific asset. Because it is signed into the file, it survives copying in a way a robots.txt rule cannot. Attaching it requires signing the asset, which almost no publishing pipeline does, so adoption rather than validity is the limit; it also binds only readers who look inside manifests, which crawlers largely do not.
content-addressed storage
Storage where an object's identifier is derived from a hash of its bytes, as in an IPFS CID, so the address itself proves what it delivers: change one byte and the identifier changes. It is a stronger immutability claim than a change receipt, which proves a difference between two dated observations. It says nothing about authorship or time: anyone can store any bytes, and the identifier does not say when. Paired with a timestamp proof it becomes a dated, verifiable copy; alone it is only a verifiable copy.
Merkle tree
A structure in which many hashes are paired and hashed upward until one root remains, so that a single root commits to every leaf and any one leaf can be proven to belong with a short path of sibling hashes. It is how one Bitcoin transaction can timestamp thousands of daily records at once.
SHA-256
The hash function that turns any input into a fixed 256-bit digest, such that changing one byte of the input changes the digest unpredictably and no two different inputs are known to share one. A published digest commits to a record's exact bytes without publishing the record.
daily seal
The once-a-day act of hashing every report produced that day into one root and anchoring that root in the Bitcoin blockchain through OpenTimestamps. It proves a record existed by that date in that exact form; it does not prove the record was correct, or that anyone read it.
byline
The named author on a page, and the machine-readable author node that should match it. Engines and readers use it as one proxy for accountability; a byline that names a person no other page corroborates carries little, and a page with none has told a reader nobody stands behind it.
dateline
The published and modified dates on a page, visible and in structured data, and whether they agree. A modified date that changes on every build is discarded as noise; a page with no date at all cannot be judged for freshness, which for a fast-moving subject is a reason to be passed over.
trust center
A page stating what a service collects, how long it keeps it, which headers and email protections it sends, which outside services it depends on, and how to reach it. Every line should be a checkable fact with the path to check it; a trust center of adjectives is marketing under another name.