While seeking out for questions for (pre-quantum) public-key cryptography, I find that the questions being asked are variatiful. Askers' confusion can come from anywhere, and lack commonality. 

Despite this, I believe the main cause is probably novices didn't properly grasp the purpose and meaning of public-key encryption, key exchange, digital signature, and sometimes other minor functionalities of PKC.

The few questions that I think has the widest audience are:

- https://crypto.stackexchange.com/q/12823/36960
- https://crypto.stackexchange.com/q/586/36960
- https://crypto.stackexchange.com/q/66760/36960
- https://crypto.stackexchange.com/q/5782/36960
- https://crypto.stackexchange.com/q/8687/36960
- *Can we find an archetypal textbook RSA question for here?*
- https://crypto.stackexchange.com/q/3820/36960