I will try to answer this as best I can. I am no expert....
The AKC is the American Kennel Club was the original kennel club in the USA in the early 1900's. The parents must be registered with the AKC or equal international kennel club. They have requirements that must be kept in order to have breeding dogs and they inspect the kennels.
The CKC (Canadian Kennel Club) is the Canadian equivalent of the AKC.
The CKC (Continental Kennel Club) your dog does not need to be registered in order to get papers, you can send in pics of the dog and get papers (lol) and viola its registered.
They also register mixed breed dogs
A lot of puppy mills and BYB use this registry as they do not have any requirements of the way the animals are kept and they do not inspect them.