You can find the pubkey of a memo user in their txs - I can use this information to encrypt a message for you https://imgur.com/a/myJAAz7
Please don't consider that a secure means of communicating. There are many issues with simply encrypting a message.
Like what? I just wanted to try it...
Encrypting provides confidentiality and some authentication but does not address things like forward secrecy or repudiation.
