# draw security protocol

It's about authenticated key exchange protocol, there are two parties party A and party B,they exchange some messages. At the end they compute the shared keys SK.

I know that it's vey cool to use Latex to set type, I really want to learn it. Any one can give me some advices? please help me! thanks

• Welcome to Tex.SX! I would suggest you rephrase your question into a more specific request. There are plenty of ways to "draw" that protocol in LaTeX, and knowing what you want in more detail might make it easier to help you. Jul 25, 2013 at 16:11

$\begin{array}{@{}l@{}c@{}l@{}} \toprule \hat{A} && \hat{B} \\ A_1=g^{a_1},\quad A_2=g^{a_2} && B_1=g^{b_1},\quad B_2=g^{b_2} \\ \bar{x}\gets_R \mathbb{Z}_q,\quad x=H_1(\bar{x},a_1,a_2) && \bar{y}\gets_R \mathbb{Z}_q,\quad y=H_1(\bar{y},b_1,b_2) \\ & \xrightarrow{\textstyle X=g^x} \\ & \xleftarrow {\textstyle Y=g^y} \\ \mathit{sid}=(X,Y,\hat{A},\hat{B}) && \mathit{sid}=(X,Y,\hat{A},\hat{B}) \\ Z_1=(YB_1)^x,\quad Z_2=(YB_2)^x && Z_1=X^{y+b_1},\quad Z_2=X^{y+b_2} \\ Z_3=Y^{x+a_1},\quad Z_4=Y^{x+a_2} && Z_3=(XA_1)^y,\quad Z_4=(XA_2)^y \\ \mathit{SK}=H(Z_1,Z_2,Z_3,Z_4,\mathit{sid}) && \mathit{SK}=H(Z_1,Z_2,Z_3,Z_4,\mathit{sid}) \\ \bottomrule \end{array}$