marchfeld

Currently supported password encryptions are mysql OLD_PASSWORD and mysql PASSWORD, so if you have migrate from application with user’s passwords encrypted with those two methods it will enable them to login.
This is useful if you don’t want to force all existing users to reset password.

Custom password encryption

Custom password encryption enable to login for imported users with other password encryption then the default md5 encryption.

wp2pgpmail

With PGP Key Generator, your visitors can generate their own private and public PGP keys. It is also possible to use the plugin to encrypt and unencrypt a PGP message.
Check <a href="https://wp2pgpmail.com" rel="nofollow ugc">https://wp2pgpmail.com</a> for more info.
Is it secure ?
<ul>
<li>All code is implememented in readable Javascript.</li>
<li>You can verify the source code.</li>
<li>No binaries are loaded from a server or used embedded.</li>
<li>No hidden transfer of plain text.</li>
</ul>
This plugin is based on the tool developed by <a href="http://ianpurton.com/" rel="nofollow ugc">Ian Purton</a>.

PGP Key Generator

A plugin to generate private and public PGP keys. No need to install any software to encrypt and decrypt PGP messages.

Custom password encryption vs PGP Key Generator