Decayfmt – a file format that corrupts itself a little every time you open it

Decayfmt is a Rust-based tool that deliberately corrupts files each time it opens them, using an “instability” parameter x encoded in the filename (e.g., photo.idcy3, note.tdcy7) to control how much data is altered per read. Images and text degrade progressively into unreadable but printable characters, and the original cannot be recovered without an external backup. The program is intended as a novelty, not as encryption, DRM, or malware.