Gaurav Kansal Blog

The extra latency and computational costs of the full TLS handshake impose a serious performance penalty on all applications that require secure communication. To help mitigate some of the costs, TLS provides an ability to resume or share the same negotiated secret key data between multiple connections. Session Identifiers  The first Session Identifiers (RFC 5246) resumption mechanism was introduced in SSL 2.0, which allowed the server to create and send a 32-byte session identifier as part of its "ServerHello" message during the full TLS negotiation which we discuss in TLS Handshake.  Internally, the server could then maintain a cache of session IDs and the negotiated session parameters for each peer. In turn, the client could then also store the session ID information and include the ID in the "ClientHello" message for a subsequent session, which serves as an indication to the server that the client still remembers the negotiated cipher suite and keys fr

Before the client and the server can begin exchanging application data over TLS, the encrypted tunnel must be negotiated: the client and the server must agree on the version of the TLS protocol, choose the cipher suite, and verify certificates if necessary. Unfortunately, each of these steps requires new packet roundtrips between the client and the server, which adds startup latency to all TLS connections. 0 ms TLS runs over a reliable transport (TCP), which means that we must first complete the TCP three-way handshake, which takes one full roundtrip. 56 ms With the TCP connection in place, the client sends a number of specifications in plain text, such as the version of the TLS protocol it is running, the list of supported ciphersuites, and other TLS options it may want to use. 84 ms The server picks the TLS protocol version for further communication, decides on a ciphersuite from the list provided by the client, attaches its certificate, and sends the respon

HTTP is a protocol used to exchange or transfer hypertext.  Hypertext is structured text that uses logical links (hyperlinks) between nodes containing text. Tim Berners-Lee and his team at CERN are credited with inventing the original HTTP along with HTML and the associated technology for a web server and a text-based web browser. Berners-Lee first proposed the "WorldWideWeb" project in 1989 — now known as the World Wide Web. The first version of the protocol had only one method, namely GET, which would request a page from a server. The response from the server was always an HTML page.                                                         Tim Berners-Lee authored/co-authored multiple RFCs (Request for Comment) including  RFC 1945  (which was published in 1996 and talks about Hyper Text Transfer 1.0), RFC 2068  (which describes HTTP/1.1 & was published in 1997), RFC 2616  (which obsoletes the RFC 2068 and made HTTP/1.1 official). Because of his extensive work towards