This paper introduces the special section on EMC and Information Security. As information security becomes more important every day, safeguarding security at the physical level is as important as at the higher levels. In recent years, instrumentation has become cheaper and more precise, computation has become faster, and storage capacity has increased. With these changes, the threat has increased of advanced attacks that were previously too difficult to carry out, not just in the military and diplomatic fields but also for general-use commercial manufactured goods. This special session focuses on the problem of reduced security concerning electromagnetic waves (electromagnetic information security), which has made attack detection particularly difficult at the physical level. As well as introducing the mechanisms of these information leaks and countermeasures, this session presents the latest research trends.