\documentclass[tikz]{standalone}
\usepackage{microtype}

\usetikzlibrary{calc}

\begin{document}
\begin{tikzpicture}[scale=0.7, every node/.style={scale=0.7}]
\foreach \x in {0, 1, 2} {
% Draw the PRF application instances.
\node (f\x) at ($2.5cm + \x*(2.5cm,0)$) [minimum size=1.25cm,rounded corners=1ex,draw] {\Large $F_k$};

% Plaintext blocks.
\node (m\x) [above of=f\x, node distance=2cm] {$m_\x$};
% Ciphertext blocks.
\node (c\x) [below of=f\x, node distance=1.5cm] {$c_\x$};
% Circle for XORs.
\node (p\x) [above of=f\x, node distance=1.2cm, circle, draw] {};

% Draw the cross'' of the XORs.
\draw[-] (p\x.north) -- (p\x.south);
\draw[-] (p\x.east) -- (p\x.west);

% Arrow: Plaintext input'd to XOR.
\draw[-latex] (m\x) -- (p\x);
% Arrow: From XOR to PRF.
\draw[-] (p\x) -- (f\x);
% Arrow: Output of PRF: the ciphertext.
\draw[-latex] (f\x.south) -- (c\x);
}

% Bent'' arrow: from the IV to the first XOR.
\node (piv) [left of=p0, node distance=1.2cm] {};
\node (iv) [left of=c0, node distance=1.5cm] {$IV$};
\draw[-latex] (iv.north) -- +(0cm,2.45cm) -- ($(piv.west) + (1.15cm,0)$);

% Bent'' arrows: going from ciphertext block c_i to XOR of plaintext block m_{i+1}.
\foreach \x in {0, 1} {
\draw[-latex] (f\x.south) -- +(0cm,-0.24cm) -| +(1.25cm,1.85cm) -- ($(p\x.west) + (2.5cm,0)$);
}
\end{tikzpicture}
\end{document}