\lstdefinelanguage{AnB}{
keywords=[1]{Agent, Number, Function, Symmetric_key, PublicKey},
keywords=[2]{Protocol, Types, Knowledge, Goals, Actions},
keywords=[3]{section, inits, rules, step, initial_state, attack_state, not, where, authenticates, on, secret, between},
keywordstyle=[1]\color{violet},
keywordstyle=[2]\color{magenta},
keywordstyle=[3]\bf,
sensitive=false, % keywords are not case-sensitive
morecomment=[l]{\#}, % line comment
morecomment=[l]{\%}, % line comment
%morecomment=[s]{/*}{*/}, % start and end delimiter
basicstyle=\footnotesize,
literate=%
{->}{\begingroup{\color{blue}$\rightarrow$}\endgroup}2%
{\{}{\begingroup{\color{blue}\{}\endgroup}1%
{\}}{\begingroup{\color{blue}\}}\endgroup}1%
% Catch {| |} s.t. we can add them to a math env. = less space between chars
{\{|}{\begingroup{\color{red}$\{\vert$}\endgroup}2%
{|\}}{\begingroup{\color{red}$\vert\}$}\endgroup}2%
{*}{$\bullet$}1,
}