Message Authentication Code

A MAC is an authentication tag that can be computed and verified with a secret parameter (e.g., a secret cryptographic key).


Modbus is a serial communications protocol originally published by Modicon (now Schneider Electric) in 1979 for use with its programmable logic controllers (PLCs). Simple and robust, it has since become a de facto standard communication protocol, and it is now a commonly available means of connecting industrial electronic devices.


  • Semigroup
  • Identity axiom: ∃a unique identity element e ∈ S such that ∀a ∈ S: a ∗ e = e ∗ a = a
    • Has identity element respect to *


MySQL is an open-source relational database management system (RDBMS). The MySQL development project has made its source code available under the terms of the GNU General Public License, as well as under a variety of proprietary agreements.