assignment.tex

\tikzstyle{blok}=[draw, fill=blue!20, minimum height=10em, minimum width=11em]

\begin{tikzpicture}[node distance=2.5cm, auto]
    \node[blok] (client) [minimum height=35em] {client};
    \path (client.east)+(7cm, 4.5cm) node (owner) [blok] {Resource owner} ;
    \path (client.east)+(7cm, 0cm) node (auth) [blok] {Authentication server};
    \path (client.east)+(7cm, -4.5cm) node (server) [blok] {Resource Server};
    \path[draw, <-, transform canvas={shift={(0, 1cm)}}] (owner) -- node [above] {Authorization Request} (client.east |- owner) ;
    \path[draw, ->, transform canvas={shift={(0, -1cm)}}] (owner) -- node [above] {Authorization Grant} (client.east |- owner) ;
    \path[draw, <-, transform canvas={shift={(0, 1cm)}}] (auth) -- node [above] {Authorization Grant} (client.east |- auth) ;
    \path[draw, ->, transform canvas={shift={(0, -1cm)}}] (auth) -- node [above] {Access Token} (client.east |- auth) ;
    \path[draw, <-, transform canvas={shift={(0, 1cm)}}] (server) -- node [above] {Access Token} (client.east |- server) ;
    \path[draw, ->, transform canvas={shift={(0, -1cm)}}] (server) -- node [above] {Protected resource} (client.east |- server) ;
\end{tikzpicture}