Cryptographic APIs Are All Poorly Designed!

I'll refrain from pointing fingers because it appears I'm dealing with either an unspoken natural law or an amazing coincidence of cosmic proportions, or just designed by the same sorts of people with the same mindsets. What I'm looking to do may not be a common use case, but it sure is a "simple" use case and I can't understand why some of it needs to be as difficult as it is and also why some of it isn't even possible! I'm about ready to start banging my head against the wall because the more I look at the problem the simpler my needs seem and the more complex and unmanageable it appears to be to get from thought in head to implemented code. Grrr...