Downloading software like MATLAB R2013a via torrents is generally unsafe and often illegal, as it typically involves bypassing licensing through "cracks" or unauthorized serial keys.
Trial Version: You can sign up for a 30-day free trial of the latest version, which includes full technical support and cloud storage. Free Alternatives (Open Source)
Downloading "full" versions of MATLAB R2013a via torrents is considered software piracy.
Instead of using untrusted sources, you can access MATLAB legally and safely through official channels. Safe & Official Ways to Get MATLAB
Version Selection: Visit the MathWorks downloads page, sign in, and use the "Select release" menu on the top left to find R2013a.
Authorized Resellers: Purchasing through authorized resellers or directly from MathWorks ensures you're getting legitimate software and support.