Security threats evolve at the rate of the latest technology
and older equipment often lacks the capacity to implement
current best-practice security algorithms within real-time constraints.
Factors such as key length and algorithm complexity
are limited by processing power when attempting to implement
any form of cryptography. In addition, other aspects
of low level industrial protocols make implementation of
security difficult. The low data transfer rate of many protocols
means that they would be adversely affected by the additional
overhead required for secure communication. Conventional
cryptographic mechanisms are also very sensitive to all levels
of electronic noise