Time Based Token Mechanism for Message Security in Critical Infrastructures

Abstract

Critical infrastructure is the term used for describing public infrastructure such as Energy, Water, and Telecommunications etc. These are usually widely distributed and networked. Such infrastructures may consist of various levels or zones and have their own security levels according their importance. Hence some of the zones may be weakly protected as may have lesser importance. These zones can thereby targeted and once compromised may be easily used to compromise other higher level zones as being in the same network, which is generally referred as Stepping Stone Attack. A Layered Security Mechanism can be implemented in such systems/infrastructure by using the principles of hash chain based methodology to prevent possible attacks. Though this eliminates stepping stone attack but does provide enough security if the communication channel is easily available for tampering. The attacker can physically tamper with the communication medium and obtain the required security level by listening to the key exchange. A time based token generation mechanism can mitigate this risk. Tokens would eventually be generated from the authentication key itself though being generated by a function involving time as one of its parameters. Thus even listening to communication medium by physical tampering wouldn’t reveal the actual user authentication key.