diff --git a/index.html b/index.html
index 803012e..5875e13 100644
--- a/index.html
+++ b/index.html
@@ -61,7 +61,7 @@ <H1 align=center><font color="#0000FF" face="Arial">
 PwdHash generates theft-resistant passwords.
 The PwdHash browser extension invisibly generates these passwords when it is installed in your browser.
 You can activate this protection by pressing F2 before you type
-your password, or by choosing passwords that start with <tt>@@</tt>.
+your password, or by choosing passwords that start with PwdHash automatically replaces the contents of these password fields with a one-way hash of the pair (password, domain-name).  <tt>@@</tt>.
 If you don't want to install PwdHash on your computer, you can generate the passwords right here.
 <ul>
 <li>Visit the <a href="http://crypto.stanford.edu/PwdHash/">Stanford project website</a>.</li>