How SSL Handshake Works?

Created on 26 May, 2023 | SSL | 125 views | 1 minutes read

Image source: top-ssl.it


SSL (Secure Sockets Layer) is a protocol that provides secure communication over the internet. It is commonly used to protect sensitive data such as passwords, credit card information, and personal details. The SSL handshake is a crucial part of establishing a secure connection between a client and a server.


The SSL Handshake Process


The SSL handshake involves a series of steps to negotiate the encryption parameters and establish a secure connection. Let's take a closer look at how the SSL handshake works:


1. Client Hello


The SSL handshake begins with the client sending a "Client Hello" message to the server. This message includes the SSL version supported by the client, a random number (ClientRandom), and a list of supported cipher suites.


2. Server Hello


Upon receiving the "Client Hello" message, the server responds with a "Server Hello" message. This message includes the SSL version chosen by the server, a random number (ServerRandom), and the selected cipher suite from the client's list of supported cipher suites.


3. Certificate Exchange


The server sends its digital certificate to the client, which contains the server's public key. The client verifies the authenticity of the certificate using a trusted Certificate Authority (CA). If the certificate is valid, the client proceeds to the next step.


4. Key Exchange


The client generates a pre-master secret and encrypts it with the server's public key obtained from the certificate. This encrypted pre-master secret is sent to the server. Both the client and the server independently derive the same master secret using their respective private keys. This master secret is used for symmetric encryption and decryption during the SSL session.


5. Session Key Generation


Using the master secret, the client and the server generate session keys that will be used for symmetric encryption and decryption of data during the SSL session.


6. Handshake Completion


Finally, both the client and the server exchange messages to notify each other that the SSL handshake is complete. They now have a secure SSL connection established, and data can be transmitted securely between them.


Conclusion


The SSL handshake is a critical process in establishing a secure connection between a client and a server. It ensures the confidentiality, integrity, and authenticity of the data transmitted over the internet. By understanding how the SSL handshake works, you can better appreciate the level of security provided by SSL and make informed decisions when it comes to protecting sensitive information.

Updated on 29 May, 2024