Connecting Cyber Security Leaders. Welcome to ISSA-UK, the UK Chapter of the ISSA. With active participation from individuals and chapters all over the world, the Information Systems Security Association (ISSA) is the largest international, not-for-profit association specifically for information security professionals. Having welcomed over 1,800 members since our beginnings in 2003, the ISSA-UK Chapter is the world's largest Chapter. At only $95 per year for membership, we offer the most value out of any security association globally.