We're trying to authenticate to a webservice, but the
provider uses a system that we are not familiar with. They sent us
our credentials, but one piece was a .key file that we are supposed
to use as our key to sha-1 hash our xml content. I'm familiar with
Amazon and Google in hashing content, however, we always had the
key in a string that was easily usable in cf_hmac. This key file is
not a string that can just be populated and I'm trying to figure
out how to use it.