Suppose I want to encrypt data, send it over the network, and decrypt it on the receiver side.
I know the elegant way to do this is by using a symmetric key to encrypt the data and an asymmetric key to send the symmetric key to the receiver so he can decrypt the data.
But I just read about another way which is to use a password based key derivation function to calculate a key on both sides. This way, no key exchanged. But this requires both sides to use the same password in the calculation of the key, so I suppose I have to send the password to the receiver at some point so he can calculate the same key and use it to decrypt.
If what I understood is correct, then I don't see the goal of using a PBKDF since I have to send something at some point. If not, then what I'm I missing?