I seem to think it is static, what i did was put amount:currency:email
into SignatureFields in the worldpay admin area in test and did a test purchase and everything worked great.
I went back into the test environment on worldpay and removed the email and left ie: amount:currency and did a test purchase and received this message on the worldpay site:
Secure Payment Page
Sorry, there was an error in processing this transaction:
The information sent from the merchant's site is invalid or incomplete. Please send the following information to the merchant:
The transaction cannot be processed due to the following:
* the MD5 signature could not be verified
Server information 02/Jan/2011 11:07:25 Server ID mm2imscs4p (WPReq-442646)
I went back in and added the email again and the test purchase went through with no errors.
I have added this into my production environment and will see if there are any problems with orders coming in. I'll post results as i have orders coming through today and should know before long.
Only Phil i would think would know if it is static or dynamic but this seems to work without changing any of the scripting i guess you could change the order of you SignatureField in the script and change it in the worldpay setup, just to make yours different then others for added security.
Cheers.




