Authenticated upload, exact bytes
The file matches a ProStamp server signature issued after an authenticated Team upload. It proves upload provenance and byte integrity; device attestation is a separate future level.
Tamper-evident by design
Verify a ProStamp proof photo.
Check whether exact bytes match an authenticated Team upload receipt, or whether an older file is only internally consistent with ProStamp's legacy shared-key label. No account required.
- Read the embedded capture time and place
- Compare exact media bytes with the recorded integrity trail
- Works for JPEG photos and Evidence Pack ZIPs
Web verifier
JPEG & Evidence Pack · server-side
For the strongest current result
Use a Team Evidence Pack carrying a ProStamp server receipt. A standalone legacy JPEG can still be checked for internal consistency, but its shared client key is not independent proof that an authentic app captured it.
Results
Three trust levels, plainly explained.
Verification follows the evidence, not just the screenshot.
Shared-key label matches
The media and embedded fields are internally consistent with the legacy HMAC. Because its key shipped in the app, this does not independently authenticate origin.
No trusted conclusion
The file may differ from its labeled bytes, lack usable metadata, or have no valid Team server receipt.
How it works
Verification follows the evidence.
Legacy captures carry an HMAC integrity label over capture fields and media bytes. Team evidence can additionally carry a server-held asymmetric receipt that the app binary cannot forge.
Capture in ProStamp
The app records the visual watermark, location context, and verification metadata at capture time.
Keep the original
Share by AirDrop, email attachment, ZIP archive, or Evidence Pack when evidence-grade verification matters.
Verify before relying on it
Use this page for signed ProStamp JPEGs, or the iOS app for videos and deeper in-app review.
Evidence Pack
Use an Evidence Pack when the file needs to survive handoff.
An Evidence Pack keeps the original media together with readable reports and context, so reviewers don’t have to guess which image, location, or timestamp belongs together.
Original files
Includes the byte-identical JPEGs or videos referenced by the report and manifest.
Reports
Adds PDF summaries that are easier to read, forward, archive, or attach to a work order.
Context
Keeps site, date range, address, GPS, verification details, and Team server receipts organized in one export.
Best use
For disputes, client approvals, inspections, or team handoff, share an Evidence Pack instead of screenshots or chat-compressed photos.
What to send for the best result
- Original ProStamp JPEG
- Evidence Pack or ZIP originals folder
- Email attachment, not an inline preview
- AirDrop transfer between Apple devices
What can weaken verification
- Messaging-app compression
- A screenshot of a photo
- Edited or resized exports
- Missing metadata or the wrong verification code