SSL (Secure Sockets Layer) is a protocol used to ensure the security of a network connection. SSL allows a server and a client (typically a web browser) to communicate securely. This prevents personal information, credit card numbers, and other sensitive data from falling into the wrong hands. SSL is often referred to as “SSL/TLS” in conjunction with its modern version, TLS (Transport Layer Security).
SSL utilizes two main cryptographic principles: symmetric cryptography and asymmetric cryptography.
Asymmetric Cryptography (Public Key Cryptography): This type of cryptography typically uses a pair of keys: one is public (public key) and the other is private (private key). Messages are encrypted using the recipient’s public key and can only be decrypted using the recipient’s private key. When an SSL connection is initiated, the server first sends its public key and a certificate to the client. The certificate proves that the key has been verified by a trusted authority.
Symmetric Cryptography: This type of cryptography is an encryption method where both parties in the communication use the same key. This key is used for both encrypting and decrypting messages. Unlike asymmetric cryptography, symmetric cryptography is generally faster. Once a secure connection is established, SSL typically uses symmetric cryptography. During the initial asymmetric encryption process, the server and client usually create a “session key” for future symmetric encryption.
In addition, SSL/TLS also employs other cryptographic principles and tools such as digital certificates and certificate authorities (CAs). A digital certificate verifies the identity of a server and is usually signed by a certificate authority. A certificate authority is an organization that issues and manages digital certificates.
In summary, an SSL certificate uses a set of complex cryptographic principles to ensure secure internet communication. Symmetric and asymmetric cryptography, digital certificates, and certificate authorities play key roles in securing an SSL connection.