In fact, public key encryption is an old technology:

The History of Cryptography - Stanford CS - Stanford University
https://cs.stanford.edu/people/eroberts/courses/.../public-key-cryptography/history.htm...
The idea of public key cryptography was first presented by Martin Hellman, Ralph Merkle, and Whitfield Diffie at Stanford University in 1976. They used a method which they referred to as the subset-sum problem, but which has been come to be known as the knapsack problem.

Understanding Public Key Cryptography and the History of RSA ...
https://www.securityweek.com/understanding-public-key-cryptography-and-history-rsa
Feb 23, 2012 - Public key cryptography uses two different keys at once, a combination of a private key and a public key. Learn more about public-key encryption and how it works and a history of RSA, the ones responsible for the breakthrough algorithm back in 1978