Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols are universally accepted standards for authenticated and encrypted communication between clients and servers. Both client and server authentication occur over SSL/TLS. SSL/TLS uses a combination of public key and symmetric-key encryption. Symmetric-key encryption is much faster than public-key encryption, but public-key encryption provides better authentication techniques. An SSL/TLS session always begins with an exchange of messages called the SSL handshake, initial communication between the server and client. The handshake allows the server to authenticate itself to the client using public-key techniques, then allows the client and the server to cooperate in the creation of symmetric keys used for rapid encryption, decryption, and tamper detection during the session that follows.

Both of these protocols support using a variety of different cryptographic algorithms, or ciphers, for operations such as authenticating the server and client, transmitting certificates, and establishing session keys. Clients and servers may support different cipher suites, or sets of ciphers. Among other functions, the SSL handshake determines how the server and client negotiate which cipher suite they will use to authenticate each other, to transmit certificates, and to establish session keys.

Key-exchange algorithms such as RSA govern the way the server and client determine the symmetric keys to use during an SSL session. The most common SSL cipher suites use RSA key exchange. The Certificate System supports RSA public-key cryptographic systems.