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Safe WebSecure Sockets Layer (SSL) is a cryptographic protocol used to establish encrypted links between web servers and web browsers. It is used to secure communications over the Internet, including web browsing, secure shell (SSH) sessions, and secure file transfer. SSL uses certificates to authenticate the server and establish a secure connection.
SSL is a descendant of the older Secure Data Network System (SDNS) protocol, which provided secure data transfers between computer hosts from 1984 to 1990. However, SSL was the first protocol to provide an end-to-end secure link between web browsers and web servers.
SSL is based on the idea of public-key cryptography, wherein two systems each possess two keys: a public key and a private key. The private key is known only to the two systems, while the public key is made available for anyone to use. When the two systems want to establish a secure connection, they exchange public keys and use them to encrypt and decrypt communications.
SSL is most commonly used to secure web communications. It is implemented on the Transport Layer Security (TLS) protocol, which is an extension to the Hypertext Transfer Protocol (HTTP). TLS is responsible for authenticating the server, negotiating encryption parameters, verifying the integrity of data, and securely exchanging data between the two systems.
SSL also provides server identity assurance by using digital certificates, thereby increasing user confidence when accessing secure web resources. A certificate authority, or CA, is an independent organization whose purpose is to verify the validity of certificates.
SSL has become a ubiquitous part of modern digital communications and is essential for secure access to web resources. It is used for virtually every type of website, from online banking to bookstores. It is also used for secure e-mail, and it is deployed in numerous software development projects, such as web services and distributed computing. SSL is a critical component in modern secure Web communications.
