Detailed HTTP/2 header compression algorithm-HPACK

In HTTP/1.1 (see [RFC7230]), the header field is not compressed. As the number of requests within a web page grows to the point where tens to hundreds of requests are needed, redundant header fields in these requests consume bandwidth unnecessarily, thereby significantly increasing latency.

TLS 1.3 Handshake Protocol

The handshake protocol is used to negotiate the security parameters of the connection. The handshake messages are provided to the TLS recording layer, where they are encapsulated into one or more TLSPlaintext or TLSCiphertext, and they are processed and transmitted according to the current active connection state. Protocol messages must be sent in a certain order (see below for the order). If the peer finds that the received handshake messages are not in the right order, they must use the "unexpected_message" alert message to abort the handshake.