Hot answers tagged public-key
The problem you described is addressed and solved in different way by the Broadcast Encryption: roughly the problem is how to encrypt a message intended to more than one recipient. You described a naive approach to the problem, your solution is, indeed, probably the simplest one. The Broadcast Encryption concept was formalized and defined by Fiat and Naor ...
You will always need to have some way of identifying the other party, be it a pre-distributed key or out-of-band procedures as you are describing. There is no purely digital method that can do this without some kind of shared knowledge.
Only top voted, non community-wiki answers of a minimum length are eligible