The How_Decrypt Ransomware is a ransomware program that was released around the end of February 2014 that targets all versions of Windows including Windows XP, Windows Vista, Windows 7, and Windows 8. The files are encrypted using RSA-2048 encryption, which makes them impossible to decrypt via brute force methods. At this time, there is method to decrypt your files that works 50% of the time. In order to purchase the decryptor for your files you need to pay a $500 USD ransom in Bitcoins.
Source: https://www.bleepingcomputer.com/virus-removal/cryptodefense-ransomware-information