In academic pursuits, we often have people (and their ideas) who are considered fundamental to the subject, such as Bayes and probability.
In cryptography, it's obvious to see that the Diffie-Hellman problem is fundamental to modern key exchange algorithms.
Can modern day symmetric encryption methods be similarly traced back to particular fundamental roots or building-blocks? If so, what are they?
Is there a common grandparent (or few) that most modern symmetric crypto such as AES or ChaCha can be undeniability related to?