\documentclass[a4paper,12pt]{article}

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{listings}
\usepackage{xcolor}
\usepackage[hidelinks]{hyperref}
\usepackage{geometry}

\geometry{margin=2.5cm}

\title{\textbf{libft\_ssl} \\ \large Cryptographic Hash Functions}
\author{lohhiiccc}
\date{}

\begin{document}

\maketitle
\tableofcontents
\newpage

\input{preliminaries}
\input{introduction}
\input{generic_interface}
\input{md5}
\input{sha256}
\input{whirlpool}

\end{document}