Hi, I'm working on setting up an interface with Authorize.net also (using the SIM method), from a VFP app. I'm stuck in that I can't find a tool that will generate the HMAC-MD5 hash value that allows passing a seed key to generate the hash. If you have found or can share anything, I would certainly appreciate it. TIA! -Mark

>I was finally able to match Authorize.net's hash value. It seems as though their Advanced Integration Method uses straight MD5 rather than HMAC-MD5 ... and upper and lower case characters make a HUGE difference! <g>
>
>>We're using the AIM method (Advanced Integration Method). The AIM documentation just referred to it as MD5 Hash but I bet they're using the HMAC-M5 just as their SIM does.
>>
>>I'll have to try that and see if the hash values match.
>>
>>Thanks for your help!
>>
>>Rodd
>>
>>>Rodd,
>>>That is correct Authorize.net is using HMAC-M5 as per there documentation on page: 7 of the Simple Integration Method Implementation Guide v1.0
>>>
>>>Chad Newman