# Security Considerations

This series of web pages uses direct calls to the unix shell and is therefore potentially vunerable to tampering and spoofing unix commands to be run as part of the typed in data.
The Apache server is configured to run PHP and unix command shell as user 'apache' and has limited privilages.
All input fields from forms and hidden variables are syntax checked (they must only contain digits).
The processing requirements on this server are very high. The processor load will regularly go to 99% when performing RSA size calculations. The size of input values are therefore checked. If extremely large values were requested for instance, the server would appear to hang.