Security in ad-hoc sensor networks with pre-loaded Time Limited Memory Keys

Securing information in ad-hoc networks [1] is a non-trivial task due to the nature of their structure. Radio communication between sensors requires encryption of the messages and physical implementation of the sensor nodes in real environment requires from the node to be tamper-protected. It is very hard to comply with these two demands, because physical tamper-protection, in most cases, is unachievable. Encryption is usually either non-symmetric or symmetric. The latter is very sensitive to key revival. It is hard to distribute key securely and more - to keep at secret during operating time. This article describes Time Limited Memory Keys (TLMK) protocol of key distribution/storage for the ad hoc sensor network based on smart sensors with limited CPU power resources. Originally protocol is designed to fulfill MICA2/MICA2DOT platform [2] specification.