SecureMark

SecureMark combines visible watermarking for images and PDF documents with invisible steganography for images. Customize visible text and image watermarks, preview the result, and export protected copies before sharing them.

Steganography embeds hidden text signatures or files within images. SecureMark includes least-significant-bit (LSB) embedding, encrypted hidden-file embedding, and experimental robust watermarking in the discrete cosine transform (DCT) domain. Its file analyzer can detect hidden content and verify digital signatures.

This community package downloads the official Linux AppImage at install time and runs the upstream build unmodified.

Files and output directories are selected through the desktop file chooser. Optional network sharing is disabled by default.

• Enable local network sharing: flatpak override --user --share=network org.ginies.secure_mark
• Allow drag and drop from a directory: flatpak override --user --filesystem=/path/to/directory org.ginies.secure_mark
• Undo these overrides: flatpak override --user --reset org.ginies.secure_mark