To obtain a verified, safe, and functional version of AutoCAD, follow the official Autodesk protocol below.
[insert download link]
Below is the information regarding official access and a technical "paper" summary regarding AutoCAD 2016 for 64-bit systems. Official Access to AutoCAD 2016 Autodesk typically provides access to the current version plus three previous versions through the Autodesk Account portal Subscribers: download verified autocad 2016 portable 64 bit