Locky encrypts your data using AES encryption and then demands bitcoins to decrypt your files. Ransomware targets a large amount of file extensions and encrypts data on unmapped network shares. Like CryptoWall, Locky also completely changes the filenames for encrypted files to make it more difficult to restore the right data. At this time, there is no known way to decrypt files encrypted by Locky. Locky is currently being distributed via email that contains Word document attachments with malicious macros.
Source: https://www.bleepingcomputer.com/news/security/the-locky-ransomware-encrypts-local-files-and-unmapped-network-shares/