Application of LED visible light communication signaling for the visually impaired

Recent progress in barrier-free technologies is encouraging helps for supporting handicapped persons and aged persons. For visually-impaired persons, though special aids including braille are prevailing, we need to provide further support. In this paper we are proposing a system for supporting moves of visually-impaired persons. Our system is not only for totally blind but also for weak sighted persons. It is based on LED-based visible light communication technologies and ubiquitous technologies for public signs. In addition, it is pointed out that such a system as proposed one is, from the security point of view, weak against side channel attack. This attack means that someone may disclose secret key of cryptography by analyzing time for its calculation through leak radio wave, and so on. The safeness of cryptography depends on confidentialness of secret key. We also consider protection against such attacks.