If anyone is interested, after firefox send shutdown, i wrote <a href="https://www.relaysecret.com" rel="nofollow">https://www.relaysecret.com</a>, its footprint is extremely small (1 lambda function that does all signing for s3 upload/download, simple frontend code that does encryption in browser using web crypto api with no 3rd party Js, no 3rd party css, no tracking. Anchor tag is used for additional random key material (so it wont leave ya browser and files will always be encrypted regardless).<p>You can roll your own too with the terraform code in it. It costs me barely anything (never go over free tier limit) to run it because files never live more than 10 days (there is a catchall lifecycle rule on the bucket) and when users select durations, i also put them in bucket prefix that has lifecycle rule place on objects under them for that duration. Note that we can't rely on lifecycle rule all the time so i also make sure when lambda is called to access the object, it checks the time-stamp, the duration and if it is meant to expire and not yet cleaned up by s3 - lambda function deletes it.<p>I learnt a ton of cool things about s3 after this neat little project and really dig the API, the lifecycle rule, signing url etc...<p>Ps: for these type of tool, you should definitely mitm it to see if plaintext file or password ever leave the browser... Relaysecret does leave one item unencrypted and that is the file name. You can change it upon upload but i like to leave it there so people know what they are downloading. I have simple idea of encrypting that with just the anchor key but haven't gotten around to put that in yet.