>Considering that we need a distinct key for each individual, that exchanging keys with each person would be a significant computational burden, and that there are more cryptographic functions needed than simply exchanging keys, new methods arose.
Isn't this exactly what RSA does, exchanging a private symmetric key with asymmetric crypto? The next paragraph makes it seem like RSA does something different.
It should answer your question, in similar spirits to that of this article. Thank you for reading and I wish you well.
GetCertificate: func(helloInfo *tls.ClientHelloInfo) (*tls.Certificate, error) {
return myGetCertificateImplementation(checkClientSupportForECDSA(helloInfo))
}
Being able to decrypt was used to prove server has the private key for the certificate, instead of signature.
RSA was was thus used for both key agreement and authentication.
This of course has the problem of all recorded traffic can be decrypted after you get your hands on the certificate's private key, maybe after the certificate has expired and admins think the key is worthless.
This was known to be a bad idea and was removed from TLS 1.3. Some banks complained, they were told to escrow using ECDHE instead if they had to make the traffic decryptable by someone with a key for some reason.
Also, do you have a good resource that explains the drawbacks of RSA key exchange in more details?