Many types of ransomware demand payment in bitcoin.[38][39] One program called CryptoLocker, typically spread through legitimate-looking email attachments, encrypts the hard drive of an infected computer, then displays a countdown timer and demands a ransom in bitcoin, to decrypt it.[40] Massachusetts police said they paid a 2 bitcoin ransom in November 2013, worth more than $1,300 at the time, to decrypt one of their hard drives.[41] Bitcoin was used as the ransom medium in the WannaCry ransomware.[42] One ransomware variant disables internet access and demands credit card information to restore it, while secretly mining bitcoins.[40]