  This paper proposes a method for identification of a user`s fixed string set
(which can be a command/instruction set for a terminal or microprocessor). This
method is fast and has very small memory requirements, compared to a
traditional full string storage and compare method. The user feeds characters
into a microcontroller via a keyboard or another microprocessor sends commands
and the microcontroller hashes the input in order to identify valid commands,
ensuring no collisions between hashed valid strings, while applying further
criteria to narrow collision between random and valid strings. The method
proposed narrows the possibility of the latter kind of collision, achieving
small code and memory-size utilization and very fast execution. Hashing is
achieved using additive & rotating hash functions in an iterative form, which
can be very easily implemented in simple microcontrollers and microprocessors.
Such hash functions are presented and compared according to their efficiency
for a given string/command set, using the program found in the appendix.
