Crypto-ransomware is a type of harmful program that encrypts files stored on a computer or mobile device in order to extort money. Encryption 'scrambles' the contents of a file, so that it is unreadable. To restore it for normal use, a decryption key is needed to 'unscramble' the file. Crypto-ransomware essentially takes the files hostage, demanding a ransom in exchange for the decryption key needed to restore the files. The first crypto ransomware was probably the infamous AIDS Trojan 3 in 1990. It was distributed on a floppy disk handed out to attendees at an international conference about the AIDS disease, and the software encrypted file names (not the files themselves), and then displayed a demand for payment to a location in Panama. The perpetrator's motivation might have been rooted more in a desire for revenge on the conference organizers than in financial gain, but in any case, the attack was ineffective. The exact reason for this wasn't published...