Stegstr

---

name: stegstr

summary: Embed and decode hidden messages in PNG images. Steganographic Nostr client for hiding data in images—works offline, no registration.

description: Decode and embed Stegstr payloads in PNG images. Use when the user needs to extract hidden Nostr data from a Stegstr image, encode a payload into a cover PNG, or work with steganographic social networking (Nostr-in-images). Supports CLI (stegstr-cli decode, detect, embed, post) for scripts and AI agents.

license: MIT

tags: steganography, nostr, images, crypto, integration, file-management, automation, cli

install:

requirements: |

- Rust (latest stable) - https://rustup.rs

- Git

steps: |

1. git clone https://github.com/brunkstr/Stegstr.git

2. cd Stegstr/src-tauri && cargo build --release --bin stegstr-cli

3. Binary: target/release/stegstr-cli (Windows: stegstr-cli.exe)

permissions:

- filesystem

metadata:

homepage: https://stegstr.com

for-agents: https://www.stegstr.com/wiki/for-agents.html

repo: https://github.com/brunkstr/Stegstr

---

# Stegstr

Stegstr hides Nostr messages and arbitrary payloads inside PNG images using steganography. Users embed their feed (posts, DMs, JSON) into images and share them; recipients use Detect to load the hidden content. No registration, works offline.

When to use this skill

CLI (headless)

Build the CLI from the Stegstr repo:

git clone https://github.com/brunkstr/Stegstr.git
cd Stegstr/src-tauri
cargo build --release --bin stegstr-cli

Binary: `target/release/stegstr-cli` (or `stegstr-cli.exe` on Windows).

Decode (extract payload)

stegstr-cli decode image.png

Writes raw payload to stdout. Valid UTF-8 JSON is printed as text; otherwise `base64:<data>`. Exit 0 on success.

Detect (decode + decrypt app bundle)

stegstr-cli detect image.png

Decodes and decrypts; prints Nostr bundle JSON `{ "version": 1, "events": [...] }`.

Embed (hide payload in image)

stegstr-cli embed cover.png -o out.png --payload "text or JSON"
stegstr-cli embed cover.png -o out.png --payload @bundle.json
stegstr-cli embed cover.png -o out.png --payload @bundle.json --encrypt

Use `--payload @file` to load from file. Use `--encrypt` so any Stegstr user can detect. Use `--payload-base64 <base64>` for binary payloads.

Post (create kind 1 note bundle)

stegstr-cli post "Your message here" --output bundle.json
stegstr-cli post "Message" --privkey-hex <64-char-hex> --output bundle.json

Creates a Nostr bundle; use `stegstr-cli embed` to hide it in an image.

Example workflow

# Create a post bundle
stegstr-cli post "Hello from OpenClaw" --output bundle.json

# Embed into a cover image (encrypted for any Stegstr user)
stegstr-cli embed cover.png -o stego.png --payload @bundle.json --encrypt

# Recipient detects and extracts
stegstr-cli detect stego.png

Image format

PNG only (lossless). JPEG or other lossy formats will corrupt the hidden data.

Payload format

Decrypted bundle: `{ "version": 1, "events": [ ... Nostr events ... ] }`. Schema: [bundle.schema.json](https://raw.githubusercontent.com/brunkstr/Stegstr/main/schema/bundle.schema.json).

Links