How encryption with asymmetric keys works?

Question

I understand that:
1. A pair public/private key is used
2. Public key can be shared publicly, but private one is never shared
3. Something encrypted with the private key can only be decrypted with the respective public key and vice-and-versa
4. Private key can be used to confirm authenticity of the message

The thing I don’t understand is how it allows a secure communication between to parties, since anyone with the public key can decrypt at least one side of the communication (i.e. the messages encrypted with the private key).

In: Technology

Answer 1

You wouldn’t encrypt with your private key to keep the message secret. Encrypting with your private key is ‘signing’ the message as you said anyone can decrypt it, but people would know it could only have come from you. What you end up doing is encrypting twice. Once with the receivers public key so only they can decrypt it and once with your private key so they know that it came from you.