When a message is sent across a connection, normally a TLS/SSL connection is used to encrypt the data in the message. To create this connection, a TLS Handshake occurs. Inside of that Handshake, the client and server exchange available cipher suites to ensure they use the same ciphers during the TLS Handshake.
How does a TLS handshake work?
Cipher suites are an integral part to the TLS Handshake, telling the client and server how to encrypt their information for the other to understand. The TLS Handshake, which connects a client and server in a secure connection, is used every day to connect to websites, so ensuring it is the most secure it can be is extremely important. Cipher suites are just one way to ensure safe and trusted connections. Code signing, proper certificate management, and secure SSH keys are all other secure connection methods that must also be implemented properly, to ensure the most secure connection to servers.