>Is anyone using Authorize.net for credit card processing from a VFP desktop app, using Authorize.net's SIM method, (for use without an SSL certificate)? The SIM option (Server Integration Method) that Authorize.net has, offers the ability to integrate CC processing "without an SSL certificate". It requires that you generate a “transaction fingerprint,” which is a hash of merchant and transaction specific information using the HMAC-MD5 hashing algorithm in order to authenticate the transaction. One piece of this is a UTC TimeStamp, which is the UTC time in seconds since January 1, 1970, and must be based on GMT time, not the local timezone. I'm using Rick's WW classes to do the http post and have a test account working, but need to add the authentication key I mention here. Just wondering if anyone has already done this. I would really appreciate any sample code for generating the timestamp and HMAC-MD5 hashing algorithm. TIA! -Mark
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>Here's a link to info on their "transaction fingerprint" for the SIM method. See the topic: "Section Three", and then "Custom Transaction Fingerprint" under that:
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>http://developer.authorize.net/guides/SIM/

I have used the SIM method for Authorize.net and I never had to send a transaction fingerprint. Is this something you require or something they require?