In the TLS 1.2 protocol, the client may send extensions. My question is: what is the format of this field? is it a list?
In TLS 1.2
client hello, the standard says:
extensions Clients MAY request extended functionality from servers by sending data in the extensions field. The actual "Extension" format is defined in Section 18.104.22.168.
server hello, the standard explicitly says it is a list. But I am not sure if this implies that the client also sends the extensions as a list:
extensions A list of extensions. Note that only extensions offered by the client can appear in the server's list.
I assume the same format is used in tLS 1.3 as well.