For over more than 19 years Sijmen is an aficionado for anything related to internet security and developing secure software. Sijmen is specialized in hacking, IT security research and performing advanced penetration testing. His specialty is breaking IT security and then explaining in a comprehensible way how he did it.Before venturing into information security, Sijmen was lead software developer at various software companies. Sijmen is an expert at finding security vulnerabilities in websites and infrastructure, and knows how his findings relate to business risks, and he is able to translate these into a solid business strategy.Sijmen is primarily interested in security in its broadest incarnation, and more specifically, in investigating security weaknesses. Ever since 1997, Sijmen has actively studied the hacker scene to gain a better understanding and deeper knowledge of their modus operandi as well as frame of mind; thus enabling him to detect, to resolve and to prevent security holes in IT systems and business processes.Since 2005, Sijmen has performed professional security tests and have now completed more than 600 security assessments. He has developed over one hundred websites with PHP, MySQL, Apache and Linux as software stack.