Questions people ask

Reading and privacy

Does the recipient need an account?

No. Anyone with Stegstr can open an "Open" image. A "Recipients" image needs the matching key.

Do I need Network on to read an image?

No. Detect runs entirely on your device, in the web version entirely in the browser tab.

Is anything stored on a server?

Only what you choose to publish with Network on: posts and reactions go to Nostr relays (public), direct messages go encrypted. Uploaded pictures go to nostr.build unencrypted. Nothing else. See privacy.

Can the hidden data be detected?

Robust and QIM images look like ordinary JPEGs and pass the classical steganalysis battery at normal settings. No hiding method is undetectable to a determined analyst with the original photo; Stegstr's goal is that the message is encrypted and the image looks unremarkable.

Compatibility

Which image formats?

Any common photo as a cover. Output is JPEG for Robust and QIM, PNG for Dot.

Can I crop, rotate or screenshot the image?

No. Recompression and resizing are survived by the default method; crops beyond about two percent, any rotation, and screenshots are not.

Do images from older versions still open?

Yes. Detect tries every method Stegstr has ever shipped.

Does it run on a phone?

The web version runs in a mobile browser for embedding and detecting. Native mobile apps are not part of the current release.

Can I use the images with other Nostr clients?

The image is just a photo to them. The events inside are standard NIP-01 events; once published to a relay through Stegstr, other clients see them normally.

Payments

Can I send money with Stegstr?

Yes, two ways. Connect a Lightning wallet in Settings (Nostr Wallet Connect) and notes can carry invoices you pay with one tap, and Zap pays the author. Notes can also carry Cashu ecash tokens, which the reader redeems into their wallet. Both work inside hidden images. See Lightning and ecash.

Does Stegstr hold my bitcoin?

No. Your wallet keeps the funds and the spending limit; Stegstr keeps only the connection string. Ecash lives at its mint until someone redeems it.

Capacity

How much fits?

Robust: 48, 163 or about 1,217 bytes depending on mode. QIM: depends on the cover and target platform, typically a few kilobytes at 1080 px. Dot: far more, but only for lossless channels. The app shows the capacity before you embed.

Why does my image fail with "too small"?

Each mode needs a minimum short edge (320, 384 or 960 pixels) and enough texture. Use a larger, more detailed photo or a smaller mode.