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One platform for content provenance Mark your work. Anyone can check it.

Encypher puts a signed label on text, images, audio, video and documents such as PDF and Word. The label shows who signed, what they declared about AI, and whether the work changed. Checking it is free.

Start freeCheck a file
Four products around one signed work: Mark adds the label as you publish, Verify lets anyone check who signed, Meter records where signed work turned up, and Trace finds your work on other sites.
Mark, Verify, Meter and Trace all work from the same signed label.
Mark
Live. Signs AI output, published work and official files. About Mark
Verify
Free. Anyone checks a label, with no account. About Verify
Meter
Early partner program. Usage reports both sides can review. About Meter
Trace
Early access. Shows where your signed work appears on selected sites. About Trace
Coverage
75+ formats for signing and verification.

Mark writes the label

Signing takes four steps: your content, sign it with your key, the label goes inside, publish as usual.
Sign once before you publish. The label travels inside the content from then on.

Mark signs work when you publish it or when your AI makes it. The label is a C2PA manifestC2PA manifest: The signed label itself: a small package inside a file that records who signed it, what they declared and how to check it., a signed record that travels with the file.

Where the format allows, Mark also adds an invisible watermarkWatermark: A mark placed in the content itself, visible or hidden, so it can be found again after the file is copied.. If the record is stripped, a soft bindingSoft binding: A watermark or fingerprint that can find a content label again after the file was copied or its metadata stripped. can lead a checker back to it.

How Mark works

Anyone can check it

Four of the five answers a provenance check can give: Verified, Modified after signing, Issuer not recognized, and No provenance found. The fifth is Could not verify.
A check reports who signed and whether the content changed. It never says whether the content is true.

The free checker reads C2PA credentials and supported watermarks. It reports each result on its own: the signature, the watermark, and any record it recovered.

A valid label shows who signed and whether the work changed. It does not say the content is true.

How Verify works

Meter and Trace use the same record

Five things an AI system can report about a story: fetched, used in an answer, cited, shown and clicked. The story's label rides through all five; only the fetch shows up in the publisher's own logs.
Of the five steps, a publisher sees only the fetch in its own logs. The rest has to be reported.
  • Meter joins signed sources with usage a partner reports. Each report says which facts Encypher saw and which the partner supplied.
  • Trace watches selected sites for your signed work. It shows each page where it appears and when, and flags new sites you do not own.

Where it plugs in

A reader requests a page through a CDN edge worker; the worker fetches the page from your unchanged server, has Encypher sign the text, and serves the signed page, caching the signed copy for the next visit. If anything fails, the original page goes through.
The edge worker adds the label on the way out. Your server stays the same, signed copies are cached, and the page always loads.
Your site
The WordPress plugin, or an edge functionEdge function: A small program that runs on a CDN's servers and can change a page as it passes through to the reader. on Cloudflare, Fastly, Akamai, CloudFront, Vercel or Netlify.
Your ads
A PrebidPrebid: Widely used open-source code that runs the ad auction before the page loads its ads. module carries the label into bid requests. How it works
Your code
A REST APIAPI: Application programming interface: a way for one program to ask another to do a job, such as sign a file. you can call from any language.
Your browser
The Chrome extension checks labels on any page.

Built on the standard we helped write

Readers see only the words of a paragraph: The town pool opens Monday at noon. Lifeguards are on duty until 6 p.m. A faint gold stitch under the lines stands for the signed label carried unseen inside the words. A checker reads it back: signed by Town Daily, made with AI: no, unchanged since signing.
The signed label travels inside the words without changing how they look. Anyone can check who signed, what they declared about AI, and whether the text changed.

Encypher wrote the C2PA method for unstructured textUnstructured text: Text with no file around it, such as an article body, a post or a chat reply, so there is no container to hold a label.. It was published as Section A.7C2PA text-provenance standard: The part of the C2PA standard that puts a signed label inside plain text, using invisible Unicode characters. of C2PA 2.3C2PA 2.3: The version of the C2PA specification, published January 8, 2026, that added the standard for unstructured text. on January 8, 2026. C2PA 2.4 carries it forward as Section A.8.

Labels follow the open C2PAC2PA: The Coalition for Content Provenance and Authenticity: the group that publishes the open standard for content labels. standard, so any C2PA checker can read them.

See our public records

For engineers

Show the technical detail
curl -X POST https://api.encypher.com/api/v1/sign \
  -H "Authorization: Bearer $ENCYPHER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text": "Your article text.", "document_title": "Headline"}'
Clients
Call the REST API with any HTTP client, against the OpenAPI 3.1 spec. Our SDKs are not yet published to PyPI or npm.
Retries
Media signing calls take an Idempotency-Key header, so a retried upload is signed once.
Limits
Volume, support and service levels are set by plan and contract. The public check needs no login.
Diligence
API reference, OpenAPI spec, service status, security documents, subprocessors.
What each standards claim means, and what it does not
StatusWhat it means
C2PA 2.2Official conformance recordGenerator product at assurance Level 1, covering 20 media types. Narrower than the formats Encypher signs and verifies.
C2PA 2.4Current targetUnstructured-text signing follows the method in Appendix A.8. Separate from the product record.
RSL 1.0 and W3C ODRL 2.2Rights outputMark can attach machine-readable rights terms at signing. Not a third-party certification.
EU AI Act transparency codeEvidence workflowMark records marking evidence for Article 50 review. It does not certify legal compliance.

Keep reading

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