e> - File existence check</li>
<li><code>ls</code> - Directory listing</li>
<li><code>cd</code> - Change directory</li>
</ul>
<h4 id="cryptography"><strong>Cryptography</strong></h4>
<ul>
<li><code>rsa</code> - RSA key generation</li>
<li><code>sign</code> - RSA signing</li>
<li><code>verify</code> - RSA verification</li>
<li><code>ec</code> - EC key generation</li>
<li><code>dh</code> - DH key generation</li>
<li><code>hash</code> - Hash encoding</li>
</ul>
<h4 id="data-structures"><strong>Data Structures<