Naturally elearning copy protection can only be achieved by the use of cryptography in order to ensure that anyone copying a file can only make any use of it if they have access to the decryption key for that file.
Having access to the right cryptographic key is not the only thing that they must have. They must have the tools and the software that know how to use the key, and the form and format it must be in if it is to be used.
As a result, if someone wants to make use of a copy of an encrypted file they need to be able to subvert the overarching administration system that grants access to keys. And that is why online administration servers are so effective at controlling access to information. Where they stand as the gatekeepers then the copier has little chance of evading the control system and producing an unencrypted version of the document for use.
Elearning copy protection is a matter of making sure that if someone who is not licensed to use your material cannot make use of a copy of your files unless you have granted them a license (which is not the same thing as them having paid to use your material(s) although in most instances that would be the case. Even when you are promoting something by giving it away ‘free’ you may still wish to retain control over the IPR that you are distributing. (In other words, free might mean that someone did not pay you a sum of money, but you are still not granting them the ability to copy and make use of your work in any way other than those that you choose to permit.)