What if the government obtains the ciphers from their creators?
Doesn't matter much. It's the keys that are important, not the design of the mechanism for applying them.
What would that have to do with anything? The AES standard, for example, was not developed by Americans. All candidates were thoroughly analyzed based on a variety of factors by a mostly academic community. It’s unlikely a backdoor exists in any of them. All encryption ciphers are “known” in the sense that all of their security rests on prevention of disclosure of the key. You can look at the algorithm, but it’s not going to give you any information to link the ciphertext with the plaintext.