Requested feature overview description.
Add in text field in upload form for MD5 hash. If the uploads hash does not match the one provided in the field, upload is prevented.

Why would it be useful?
With large files, this would prevent uploads that are corrupted during the upload. This also lessens steps when uploading large files as now you do not need to compared the MD5 of the upload to local copy after the upload.

Additionally, upload form could check if post with stated MD5 already exsists and notify the uploader.

What part(s) of the site page(s) are affected?
Upload form.
Uploading.

Out of curiosity, could an admin please inform us how often do file upload corruptions occur?

We do recommend using direct URL upload so that takes care of those couple instances where images were corrupted with users using connection that's less reliable than dial up.

With large video files, I don't have straight up data until I go and manually look, but I would say there to be under twenty broken or corrupted video files where handful of them were corrupted during upload process and rest were corrupted by users encode (mostly by user using VLC).

Still, just like when downloading large files like disc image files, checking MD5 after download is pretty crusial step to ensure the file is indeed intact, no matter how reliable your connection is. That's why I do always check hash of videos I upload here, especially when they are hitting 100 MB mark.

Wait, is this something that I should do whenever I upload a post?

MyNameIsOver20charac said:
Wait, is this something that I should do whenever I upload a post?

If you're uploading a post it's best to check https://saucenao.com/ to see if there's similar versions on E6, otherwise people can upload the same image in a worse quality.

You could check the MD5 before uploading but E6 normally calculates it and throws an error if there's already a matching post. Really, for images, you're better off using that site first, as it'll check for different quality and resolutions of the same post.

Obviously a 1080p image has a different MD5 compared to a 4k one so the upload form would allow both versions, despite that one should really be flagged for deletion.

MyNameIsOver20charac said:
Wait, is this something that I should do whenever I upload a post?

If you want to check that your file wasn't corrupted or othervice altered during upload, yes.
However usually this is problem with large files and/or if you have bad and unreliable internet connection.