Thanks again, Sergey! Crypt works beautifully. This is scarey.. My Authorize.net interface is actually working! <g> A big Mahalo to you!

>Hi Mark,
>
>Sorry, I didn't read your post carefully enough. Maybe Chilkat Crypt ActiveX (commercial) will work for you? It comes with VFP sample code http://www.example-code.com/foxpro/hmac_md5.asp and has 30 days trial.