Add random notes about possible weaknesses

    <p>The use of the <code>-b</code> option is discouraged, since when it is

    used the unencrypted password appears on the command line.</p>

    <p>When using the <code>crypt()</code> algorithm, note that only the first

    8 characters of the password are used  to form the password. If the supplied

    password is longer, the extra characters will be silently discarded.</p>

    <p>The SHA encryption format does not use salting: for a given password,

    there is only one encrypted representation. The <code>crypt()</code> and

    MD5 formats permute the representation by prepending a random salt string,

    to make dictionary attacks against the passwords more difficult.</p>

</section>

<section id="restrictions"><title>Restrictions</title>