Transport Layer Security (TLS) is the successor to SSL and is a cryptographic protocol that ensures privacy, authentication, and data integrity between two communicating computer applications over a network.
Thank you for reading this post, don't forget to subscribe!- TLS is more secure and efficient than SSL. It resolves the flaws in SSL and is now the industry standard for secure online communication.
TLS is used in several critical security applications, including:
- HTTPS (secure web browsing),
- VPNs (Virtual Private Networks),
- Email security protocols (like SMTPS, IMAPS),
- VoIP communications,
- and secure file transfers.
The latest version is TLS 1.3, which eliminates outdated cryptographic algorithms and provides faster handshakes and improved security.
SSL/TLS Handshake Process:
The SSL/TLS handshake is the process that establishes a secure encrypted communication session between a client (e.g., browser) and a server.
Here are the key steps:
1.) Client Hello:
The client initiates the communication by sending a “Client Hello” message. This message includes the TLS version, a list of supported cryptographic algorithms (cipher suites), and a random number used for key generation.
2.) Server Hello:
The server responds with a “Server Hello” message. It selects the strongest supported cryptographic algorithm from the list provided by the client. The server also sends its digital certificate (usually X.509) to authenticate itself.
3.) Certificate Verification and Key Exchange:
The client verifies the server’s certificate using a trusted Certificate Authority (CA). If the certificate is valid, the client generates a pre-master key, encrypts it with the server’s public key, and sends it to the server. The server then uses its private key to decrypt it and generate the same session key.
4.) Session Key Generation:
Both client and server now derive the same symmetric session key based on the shared secret. This key is used for encrypting and decrypting the data exchanged in the session.
5.) Secure Communication Begins:
From this point on, all data exchanged between the client and server is encrypted using the session key, ensuring confidentiality, integrity, and authenticity.
Why SSL/TLS is Used:
SSL/TLS is used to:
- Protect sensitive data during transmission (e.g., login credentials, payment details),
- Ensure authentication of the communicating parties,
- Prevent eavesdropping, tampering, and forgery,
- Enable secure web services, especially through HTTPS.