Where your file actually goes
Most sharing services work in two steps: you upload your file to their computers, and the other person downloads it back off them. Your file sits on a stranger's hard drive in between.
This tool skips that. Once both browsers are open, they connect to each other and the file goes straight across, scrambled the whole way. We only help the two of you find each other — a bit like giving out a phone number. We never see the file itself.