i'm at the office of an electronics frontier foundation in san francisco to talk with cooper quinton about how ransom ware works. what is ransom ware? >> a type of malicious computer software, malware, that encrypts all your files so you no longer have access to them, you can no longer review them. then it charges you to decrypt them. it usually asks for payment in bit coin, a type of digital currency. >> and on a computer screen, if you're attacked, what does that look like? >> i have a demonstration here. here's my computer screen. and i have all my important files. here's my picture of my cat. here's other pictures of my family. tax forms, et cetera. and i have this file here which is a file that was maybe sent to me by somebody that i know or it was on a usb drive or maybe i downloaded it from the internet. and it says silly fun time and tacos. i'm about to run it because tacos sound great. when i run it, though, i get -- oops. all of your important files have been encrypted. suddenly none of my files are accessible anymore. if i try to open my cat picture, it's no longer there.