Per-recipient attribution
Each shared copy gets an invisible mark tied to the recipient name you assign, so a leaked version can be traced back to that copy.
PrivateMark
PrivateMark on-device app for watermarking photos and documents to trace leaked copies, plus Hidden Photo for revealing a concealed image.
Overview
PrivateMark is an iPhone, iPad, and Mac app for embedding invisible, per-recipient watermarks in photos and documents so you can identify which copy was leaked. You assign a recipient name, protect the file on-device, and later import a surfaced copy to see whose version it matches, with statistical confidence.
The same product also includes Hidden Photo, a separate workflow for sending a real image behind an innocent cover image. In that mode, the recipient opens the protected file inside PrivateMark to reveal the hidden photo, with the source describing both a fully offline file mode and a photo mode that can use an encrypted iCloud copy to survive chat-app recompression.
Core features
On-device processing
Watermarking and reading happen directly on the device, with no PrivateMark servers or uploads involved.
Covert sharing
The shared file keeps a normal filename and clean metadata, and the mark is embedded in the pixels rather than metadata.
Leak-resistant mark
PrivateMark is built for real-world sharing paths and is described as surviving WhatsApp and iMessage recompression, screenshots, and cropping.
Document watermarking
The app also protects PDF, Word, and PowerPoint files using marks in embedded images, text, and file fingerprinting.
Hidden Photo sharing
Hidden Photo lets you send a cover image while a trusted contact reveals the real photo inside PrivateMark with a shared passphrase or encrypted iCloud-backed flow.
Common use cases
Trace leaked copies
Send a sensitive photo or document to a specific person and keep a record of which copy went to which recipient if it later appears elsewhere.
Protect business documents
Share board decks, contracts, reports, or other office files while preserving the ability to identify the source of a forwarded copy.
Hide a private photo behind a cover image
Send an image that looks ordinary in the chat or camera roll but reveals a different photo to the intended recipient inside PrivateMark.
Keep a hidden photo fully offline
Use the file mode when you want the hidden image to stay entirely on your device and travel only as an encrypted file through AirDrop, Mail, or Files.
Share hidden photos through chat
Use the photo mode when you want a hidden photo to pass through chat apps and survive recompression, while keeping the real image protected by encryption and your passphrase.
Pros and Cons
Pros
- Works on-device with no PrivateMark backend, no uploads, and no user accounts.
- Supports photos and several document formats, not just image files.
- Designed to survive common sharing damage such as recompression, screenshots, and cropping.
- Includes a second workflow, Hidden Photo, for sending a concealed image behind a cover photo.
- The privacy policy says recipient names are encrypted at rest and can sync through a user's own private iCloud setup.
Cons
- The pricing page is unavailable, so only the launch-offer and in-app pricing shown on the home page can be confirmed from the source.
- Some limits are acknowledged by the product itself: a screenshot of a text-only document is not attributable, and very degraded copies may fall back to file recognition without naming a recipient.
FAQ
Which devices does PrivateMark run on?
PrivateMark runs on iPhone, iPad, and Mac. The source also notes iOS 17+ for iPhone and iPad, and that one purchase covers all of those devices.
Do my photos or recipient registry get uploaded anywhere?
No. The app is designed to work on-device, with no PrivateMark backend. The privacy policy says photos, registry data, and investigations stay on your devices, with only anonymous content-free analytics leaving the app.
How do I share protected files or hidden photos?
The source says watermarked photos can be shared through WhatsApp, iMessage, Mail, AirDrop, and other normal sharing paths. Hidden Photo also has a file mode for AirDrop, Mail, Files, and “send as Document,” plus a photo mode for chats.
What happens if a leaked copy is too damaged to identify?
PrivateMark says the watermark is imperceptible and survives common degradation such as recompression, screenshots, and cropping. If a copy is too degraded to read, the app can fall back to a perceptual fingerprint to confirm the file is yours, but it will not guess a recipient.
Is PrivateMark legal to use?
The product pages describe watermarking your own photos and documents before sharing them and say this is generally lawful. PrivateMark itself only provides the attribution fact; it does not tell you what action to take with it.
Quick Facts
- Category
- Privacy / Security
- Platforms
- iPhone, iPad, Mac
- Source domain
- privatemark.app
- Primary use
- Per-recipient watermarking and hidden-photo sharing
- Pricing shape
- App Store purchase with a launch offer; pricing page currently returns 404
- Account required
- No
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