Encrypt & Decrypt Text Online is an online tool that let you crypt text. You can set a key to crypt your string or leave it to the default key. After you crypt a text you can decrypt it to view the original message.
It's just HTML, CSS and Javascript (jQuery) so you can download this repo and launch index.html. You can host it where you want or use my online version here: https://albertoreineri.it/crypt/
Simply put you text into the Encrypt textarea, choose a numeric key and press "Crypt". Same procedure to Decrypt it.
Watch the video tutorial here: https://albertoreineri.it/crypt/tutorial.mp4
Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.
Please make sure to update tests as appropriate.