Autonomous Database mandates a secure connection that uses Transport Layer Security (TLSv1.2).
Mutual TLS (mTLS) Authentication: requires either Oracle Wallet or Java KeyStore (JKS) where both the client and Autonomous Database authenticate each other.
The wallet and keystore files are included in the client credentials
.zipfile that is available by clicking Database connection on the Oracle Cloud Infrastructure Console
TLS Authentication: The client computer matches the server’s CA root certificate against the client’s list of trusted CAs. If the issuing CA is trusted, the client verifies that the certificate is authentic. This allows the client and Autonomous Database to establish the encrypted connection before exchanging any messages.