notation.sty

%Copyright 2018, Andrea Proietto
%Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
%
%The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
%
%THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

%=============================================
% This is a reduced version of a larger package, and contains an environment definition that enables quick drawing of cryptographic games, with the purpose of being as least intrusive, and most readable as possibile to the document writer/programmer.
% It is partially founded on the work of "asmeikal", found in GitHub: (https://github.com/asmeikal/crypto16)

\ProvidesPackage{notation}[2018/09/21 v1.0-crypto The Notation]

% Required for crypto games
\RequirePackage{tikz}
\usetikzlibrary{arrows,shadows} % shadows for the entities, arrows for the messages
\RequirePackage{xparse} % Improved macro/environment definition commands

% Cryptography
%
% Evaluate UAR [math mode]
\newcommand{\pickUAR}{\mathrel{{\leftarrow}\vcenter{\hbox{\scriptsize\rmfamily\upshape\!\!\textsf{\$}}}}}
% Default challenger
\newcommand{\challenger}{\textsf{C}}
% Default adversary
\newcommand{\adversary}{\textsf{A}}
% Default distinguisher
\newcommand{\distinguisher}{\textsf{D}}
% Cryptogame [math mode]
\NewDocumentCommand{\cryptog}{m O{\Pi} O{\adversary}}{\textsc{Game}^{\textsc{#1}}_{#2, #3}}
% Hybrid game [math mode]
\NewDocumentCommand{\hybridg}{m O{\Pi} O{\adversary}}{\textsc{Hyb}^{\textsc{#1}}_{#2, #3}}

% Acronyms
%
% Independent and Identically Distributed
\newcommand{\iid}{\textsc{iid}}
% Uniformly At Random
\newcommand{\uar}{\textsc{uar}}
% Probabilistic Polynomial Time
\newcommand{\ppt}{\textsc{ppt}}

% Secret Key Encryption
\newcommand{\ske}{\textsc{ske}}
% Public Key Encryption
\newcommand{\pke}{\textsc{pke}}
% Message Authentication Code
\newcommand{\mac}{\textsc{mac}}

% One-Way Function
\newcommand{\owf}{\textsc{owf}}
% One-Way Permutation
\newcommand{\owp}{\textsc{owp}}
% PseudoRandom Generator
\newcommand{\prg}{\textsc{prg}}
% PseudoRandom Function
\newcommand{\prf}{\textsc{prf}}
% PseudoRandom Permutation
\newcommand{\prp}{\textsc{prp}}
% TrapDoor Permutation
\newcommand{\tdp}{\textsc{tdp}}

% Chosen Plaintext Attack
\newcommand{\cpa}{\textsc{cpa}}
% Chosen Ciphertext Attack
\newcommand{\cca}{\textsc{cca}}
% Universally unForgeable from Chosen Message Attack
\newcommand{\ufcma}{\textsc{ufcma}}

% Discrete Logarithm assumption
\newcommand{\dl}{\textsc{dl}}
% Decisional Diffie-Hellman assumption
\newcommand{\ddh}{\textsc{ddh}}
% Computational Diffie-Hellman assumption
\newcommand{\cdh}{\textsc{cdh}}

% Goldreich-Goldwasser-Micali construct
\newcommand{\ggm}{\textsc{ggm}}

% Function classes and relations
%
% Computational indistinguishability
\newcommand{\compindist}{\approx_\textsc{c}}
% Statistical indistinguishability
\newcommand{\statindist}{\approx_\textsc{s}}

%%%%%%%%%%%%%%%%%%%%%%%%
% Cryptosequences
%%%%%%%%%%%%%%%%%%%%%%%%

% Define counters
\newcounter{preinstance}
\newcounter{instancecount}
\newcounter{sequencecursor}
\newcounter{intransientfigure}
\setcounter{intransientfigure}{0}
\newcounter{looplabel}

\newcommand{\cseqcraftfloat}{
    \ifnum\@floatpenalty<0\relax
    \else
        \setcounter{intransientfigure}{1}
        \begin{figure}[htbp]
        \centering
    \fi
}

% Styles
\tikzstyle{msgstyle}=[->, >=angle 60]
\tikzstyle{inststyle}=[rectangle, draw, anchor=west, minimum height=0.8cm, minimum width=1.6cm, fill=white, drop shadow={opacity=1,fill=black}]

% Internal commands
%
% Diagram spacing
\newcommand{\cseqdelay}{\stepcounter{sequencecursor}}

% Message: from, fromtext, msgtext, to, totext
\newcommand{\cseqmessager}[5]{
    \stepcounter{sequencecursor}
    \path (#1)+(0, -\thesequencecursor*\unitfactor-0.7*\unitfactor) 
        node (tail) {} node [anchor = east] {#2};
    \path (#4)+(0, -\thesequencecursor*\unitfactor-0.7*\unitfactor)
        node (head) {} node [anchor = west] {#5};
    \draw [msgstyle] (tail) -- (head)
        node [midway, above] {#3};
}

% Message: from, fromtext, msgtext, to, totext
\newcommand{\cseqmessagel}[5]{
    \stepcounter{sequencecursor}
    \path (#1)+(0, -\thesequencecursor*\unitfactor-0.7*\unitfactor) 
        node (tail) {} node [anchor = west] {#2};
    \path (#4)+(0, -\thesequencecursor*\unitfactor-0.7*\unitfactor)
        node (head) {} node [anchor = east] {#5};
    \draw [msgstyle] (tail) -- (head)
        node [midway, above] {#3};
}

% New participant
% \cseqentity[edge distance]{var}{name:class}
\newcommand{\cseqentity}[3][0]{
    \stepcounter{instancecount}
    \path (inst\thepreinstance.east)+(#1,0)
        node[inststyle] (inst\theinstancecount) {#3};
    \path (inst\theinstancecount)+(0,-0.5*\unitfactor)
        node (#2) {};
    \tikzstyle{instcolor#2}=[]
    \stepcounter{preinstance}
}

% Entity computation
\newcommand{\cseqcompute}[3]{
    \stepcounter{sequencecursor}
    \path (#1)+(0,-\thesequencecursor*\unitfactor-0.7*\unitfactor)
        node [anchor = #3] {#2};
}


% API Commands
%
% Challenger computation
\newcommand{\cseqchallenger}[1]{
    \cseqcompute{C}{#1}{west};
}
% Adversary computation - optional orientation as first argument: [east|west]
\newcommand{\cseqadversary}[2][east]{
    \cseqcompute{A}{#2}{#1};
}
% Distinguisher computation
\newcommand{\cseqdistinguisher}[1]{
    \cseqcompute{D}{#1}{east};
}


% Message from adversary to challenger
\newcommand{\send}[3]{
    \cseqmessager{A}{#1}{#2}{C}{#3}
}
% Message from challenger to adversary
\newcommand{\receive}[3]{
    \cseqmessagel{C}{#1}{#2}{A}{#3}
}
% Message from adversary to distinguisher - cryptoredux only
\newcommand{\invoke}[3]{
    \cseqmessagel{A}{#1}{#2}{D}{#3}
}
% Message from distinguisher to adversary - cryptoredux only
\newcommand{\return}[3]{
    \cseqmessager{D}{#1}{#2}{A}{#3}
}


% Arguments: Identifier (used as label) | description | challengername
\NewDocumentEnvironment{cryptogame}{m m m O{2.2}}
{ % Crypto-game BEGIN

    \cseqcraftfloat

    \begin{tikzpicture}

        % Set unit measurements
        \setlength{\unitlength}{1cm}
        \def\unitfactor{0.6}

        % Set counters
        \setcounter{preinstance}{0}
        \setcounter{instancecount}{0}
        \setcounter{sequencecursor}{0}
        \node[coordinate] (inst0) {};
        
        % Loop macros
        \newcommand{\cseqbeginloop}{
            \ifnum\thelooplabel=0
            \setcounter{looplabel}{\thesequencecursor}
            \stepcounter{looplabel}
            \else \PackageError{notation}{Attempting to nest loops in a cryptosequence. Close the former loop first}
            \fi
        }

        \newcommand{\cseqendloop}{
            \ifnum\thelooplabel=0
                \PackageError{notation}{No loop to close here}
            \fi
            \ifnum\thelooplabel>\thesequencecursor\relax
                \PackageError{notation}{Closing an empty loop}
            \fi
            \draw[->](A)+(-0.2, -0.15-\thesequencecursor*\unitfactor-0.7*\unitfactor)
            .. controls +(-0.6, -1.3)
            and         +(-0.6, +1.3)
            ..          +(-0.2, 0.15-\thelooplabel*\unitfactor-0.7*\unitfactor);
            \setcounter{looplabel}{0}
        }

        % Add the game's participants
        \cseqentity{A}{$\adversary$}
        \cseqentity[#4]{C}{$\challenger^{\textsc{#3}}$}

}
{ % Crypto-game END

        \ifnum\value{instancecount}>0
            \foreach \t [evaluate=\t] in {1,...,\theinstancecount}{
                \draw[dotted] (inst\t) -- ++(0,-\thesequencecursor*\unitfactor-2.2*\unitfactor);
            }
        \fi
    \end{tikzpicture}

    \ifnum\value{intransientfigure}=1
        \caption{#2}
        \label{cryptogame:#1}
        \end{figure}
        \setcounter{intransientfigure}{0}
    \fi
}



% Arguments: Identifier (used as label) | description | challengername | Second adversary name
\NewDocumentEnvironment{cryptoredux}{m m m m O{2.2}}
{ % Crypto-game BEGIN

    \cseqcraftfloat

    \begin{tikzpicture}

        % Set unit measurements
        \setlength{\unitlength}{1cm}
        \def\unitfactor{0.6}

        % Set counters
        \setcounter{preinstance}{0}
        \setcounter{instancecount}{0}
        \setcounter{sequencecursor}{0}
        \node[coordinate] (inst0) {};
        
        % Loop macros
        \newcommand{\cseqbeginloop}{
            \ifnum\thelooplabel=0
            \setcounter{looplabel}{\thesequencecursor}
            \stepcounter{looplabel}
            \else \PackageError{notation}{Attempting to nest loops in a cryptosequence. Close the former loop first}
            \fi
        }

        \newcommand{\cseqendloop}{
            \ifnum\thelooplabel=0
                \PackageError{notation}{No loop to close here}
            \fi
            \ifnum\thelooplabel>\thesequencecursor\relax
                \PackageError{notation}{Closing an empty loop}
            \fi
            \draw[->](D)+(-0.2, -0.15-\thesequencecursor*\unitfactor-0.7*\unitfactor)
            .. controls +(-0.6, -1.3)
            and         +(-0.6, +1.3)
            ..          +(-0.2, 0.15-\thelooplabel*\unitfactor-0.7*\unitfactor);
            \setcounter{looplabel}{0}
        }

        % Add the reduction's participants
        \cseqentity{D}{$\distinguisher^{\textsc{#4}}$}
        \cseqentity[#5]{A}{$\adversary$}
        \cseqentity[#5]{C}{$\challenger^{\textsc{#3}}$}

}
{ % Crypto-game END

        \ifnum\value{instancecount}>0
            \foreach \t [evaluate=\t] in {1,...,\theinstancecount}{
                \draw[dotted] (inst\t) -- ++(0,-\thesequencecursor*\unitfactor-2.2*\unitfactor);
            }
        \fi
    \end{tikzpicture}
    
    \ifnum\value{intransientfigure}=1
        \caption{#2}
        \label{cryptoredux:#1}
        \end{figure}
        \setcounter{intransientfigure}{0}
    \fi
}