These functions are only available if the interpreter has been
compiled with the --with-cybercash=[DIR].
This extension has been moved from PHP as of PHP 4.3.0 and now
CyberCash lives in PECL.
If you have questions as to the latest status of CyberCash then
the following CyberCash Faq
will be helpful. In short, CyberCash was bought out by VeriSign and
although the CyberCash service continues to exist, VeriSign encourages
users to switch. See the above faq and PECL link for details.