Prof. Keith Martin is a professor of information security at Royal Holloway, University of London. He has broad research interests, with a focus on application of cryptography and geopolitical aspects of cyber security. Keith has authored three books on cryptography and cyber security, over 100 research publications in cyber security, as well as articles in the popular and professional press. He co-designed Royal Holloway’s online postgraduate programmes in cyber security and has overseen its cyber security doctoral programme. He has also presented courses on cyber security to a wide range of audiences, including specialist industrial short courses, the general public and schools.
This is just such an excellent resource. For people new to the subject, there are clear explanations and examples. Anyone wanting a refresher will find that all basic areas are covered. This is also very well organized so it's easy to find whatever topic you're looking for.