Burrows–Abadi–Needham logic
Burrows–Abadi–Needham logic (also known as the BAN logic) is a set of rules for defining and analyzing information exchange protocols. Specifically, BAN logic helps its users determine whether exchanged information is trustworthy, secured against eavesdropping, or both.
Source: Wikipedia — Burrows–Abadi–Needham logic (CC BY-SA 4.0)