The Ransomware in question has been identified as a variant of ransomware known as WannaCry (also known as 'Wana Decrypt0r,' 'WannaCryptor' or 'WCRY').
Like other ransomware variants, WannaCry also blocks access to a computer, encrypts its files and demands money (bitcoin) to unlock it.
Another independent security researcher, MalwareTech, reported that a large number of U.S. organizations (at least 1,600) have been hit by WannaCry, compared to 11,200 in Russia and 6,500 in China.
How to Protect Yourself from WannaCry
Firstly, if you haven't patched your Windows machines and servers against EternalBlue exploit (MS17-010), do it right now.
To safeguard against such ransomware infection, you should always be suspicious of uninvited documents sent an email and should never click on links inside those documents unless verifying the source.
Keep a good backup routine in place that makes copies of your data to an external storage device that is not always connected to your PC.
Make sure that you run an active anti-virus security suite of tools on your system (though there are some reports that some anti virus suites may not have stopped this infection), and most importantly, always browse the Internet safely.