The Aurora Ransomware is a Windows infection that encrypts your files and then demands a ransom in bitcoins in order to get the decryption key. This ransomware has had numerous variants released with the most active current one being the one that appends the .Nano extension.

https://www.bleepingcomputer.com/news/security/how-to-decrypt-the-aurora-ransomware-with-auroradecrypter/