!!! Overview
[{$pagename}] ([TLS 1.3]) in all [TLS Handshakes], the server [MUST] send the [{$pagename}] message immediately after the [ServerHello] message. 

This is the first message that is [encrypted] under keys derived from the [server_handshake_traffic_secret].

The [{$pagename}] message contains [TLS extensions] that can be protected, i.e., any which are not needed to establish the [cryptographic] context, but which are not associated with individual [certificates]. The client [MUST] check [{$pagename}] for the presence of any forbidden [TLS extensions] and if any are found [MUST] abort the [TLS Handshake] with an [illegal_parameter] [TLS Alert Message].

Structure of the [{$pagename}] message:
%%prettify 
{{{
struct {
    Extension extensions<0..2^16-1>;
} EncryptedExtensions;
}}} /%

!! More Information
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[{ReferringPagesPlugin before='*' after='\n' }]