Encryption Prototype

Hello,
This is a simple encryption prototype that i made :)!

All the encrypted text is unique.

Please do not redistribute this project!

(make sure to tell the key to your friends personally and always use that key unless it gets leaked, otherwise they wont be able to read the text)
2 versions:
command line version (66mb)
Rust version(944kb)

downloads are below

keyfinding challenge:

9095910791069099911090939112911190289107910690289098910191069096910191069099902891129100909790289103909791179029902891129117910890979028911291009097902890989107910491049107911591019106909990289105909791119111909390999097902891019106902891129100909790289095910791059105909791069112911190289107909890289112910090979028910891109107909991109093910590549028909490939106909391069093