[Solved] Sending and receiving

OK so I have listened to a number of lectures on asymmetric encryption but there is one thing thats never been clarified to me

So in your example Bob is receiving a message from “sender”. To my understanding Bob gives his public key to the sender. The sender uses that public key to encrypt the data being sent to Bob. Bob then uses his private key to decrypt the data he receives.

So now for my question.

Lets say that Bob and the other person are both sending and receiving encrypted information.

Do Bob and the other person both use a separate instance of the same encryption type?

For example, Bob has his own private key, the other person also has his own private key. Bob and the other person both have unique public keys that were created and paired with each of their own private keys. Bob and the other person then exchange public keys. Bob uses the other persons public key to enrcypt information that he is sending, and the other person uses his private key to decrypt Bobs data. And at the same time the other person is using Bobs public key to encrypt data being sent to Bob. Bob then uses his own private key to decrypt the data that he gets from the other person.

if this is true I find it a little misleading that asymmetric encryption uses two keys. Its more like 2 x 2 keys.

Anyway I am really liking your lessons so far. Sorry for the very long wordy question.

You are correct is everything you say. The reason they are said to have two keys is because they are generated together and are cryptographically related. The other keys for the conversation are not part of the creation of the keys.

The number of keys required for communication is an important distinctions as you point out.

With symmetric if you want to exchange data between for example 10 people that would require 45 keys!
N(N – 1)/2 = number of keys required

Making asymmetric much better for this.

To add some extra fun in the mix. The asymmetric algorithms that we know today don’t have long to live due to quantum computers. Maybe 5-15 years. They will need to be replaced… by what, we don’t know. No one has created alternatives yet.

This will be covered in Volume 4.

Hope that helps.