25-year-old Roy Chaoran Sun, a former student of Purdue University, has been sentenced to 90 days in prison for hacking into the schools computer systems to change his grades. Sun has been sentenced to four years, but he will spend most of the sentence on supervised probation. Sun wasnt the only one involved in the scheme. Mitsutoshi Shirasaki and Sujay Sharma were also charged back in June 2013. According to Jconline.com, Sharma was sentenced to …