I couldn't find one, so I decided to make it myself, I went ahead and made it.
I believe you'll understand it once you see the code, but just so you know, no data is sent to any servers.
Feel free to give it a try!
https://kuenytum.jp/crypt
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意外となかったので作ってみた。
コードを見たら理解できると思うけど、一切サーバーへデータは送られない。
ぜひ使って下さいな！
https://kuenytum.jp/crypt