The KM[x] (Cipher Message[with xxx]) set of crypto instructions seems to do the same things as PCC (Perform Cryptographic Computation). I haven't checked every option in excruciating detail, but for the common ones (DES, 3DES, AES) there is at least a lot of overlap.
For new code, what should I choose, and why? Both seem to support encrypted keys, so that isn't the differentiator. For old code, where I have (say) a DES routine in software that I would like to replace, are the criteria different? (Of course I am aware that perhaps calls to ICSF are the overall better choice, but I would still like to understand the reasons for the existence of these two sets of instructions.) Thanks... Tony H.