Did you find that Authorize.net was using the HMAC-MD5 flavor?

>Rodd,
>I'm currently working on my Authorize.net implementation. I ran into some confusion about MD5. There are actually 2 flavors. MD5 and HMAC-MD5. HMAC-MD5 uses a "key" along with other values to determine the hash value. I used a ActiveX control called Hash ActiveX Objects Version 1.3 available for download at http://www.newobjects.com/product.asp?Category=49. It runs about $37.50 for a single computer license. It was easy to implement and the help is pretty good even though the samples are for VB.
>
>BTW, the sample control only returns back the first 8 bytes and I did modify the hash so that it was in lower case like Authorize.net
>
>Chad Newman