Mutual TLS Two-Way Handshake {#batch-uploading-rest-m-tls-two-way-hs}
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With mTLS, the authentication message exchange between client and server is called an **SSL handshake** . This sequence summarizes the components of the mTLS process handshake:

1. **Client hello**---The client initiates a connection by sending a "Client Hello" message. The message includes supported cryptographic algorithms and the client's public key.
2. **Server hello**---The server responds with a "Server Hello" message, including its public key and a digital certificate issued by the DigiCert trusted Certificate Authority (CA).
3. **Client certificate request**---The server requests a certificate from the client for authentication.
4. **Client certificate**---The client sends its certificate, which is validated by the server.
5. **Handshake completion**---Both parties exchange keys and establish a secure, encrypted communication channel.  
   After the handshake completes successfully, the client and server use the **symmetric key** for encrypting and decrypting data.