STARTTLSllä

STARTTLSllä is a method used to upgrade a plain text connection to an encrypted (TLS) connection. It is often employed in email protocols like SMTP, POP3, and IMAP, as well as other network protocols like XMPP. The process involves a client initiating a connection to a server using the standard, unencrypted port. Once the connection is established, the client sends a specific command, STARTTLS, to the server. If the server supports STARTTLSllä, it will respond positively, indicating its readiness to upgrade the connection. Following this, the client and server engage in the TLS handshake process, negotiating encryption algorithms and exchanging certificates. Upon successful completion of the handshake, the entire communication session between the client and server is encrypted, protecting sensitive data from eavesdropping. This is distinct from implicit TLS, where encryption is established on a separate, dedicated port from the outset. STARTTLSllä offers backward compatibility, allowing older clients that do not support STARTTLSllä to still connect to the server, albeit without encryption. This flexibility makes it a widely adopted security mechanism in various network applications.