Reading the Web Socket RFC, at 5.1 it says:
a client MUST mask all frames that it sends to the server (see Section 5.3 for further details). (Note that masking is done whether or not the WebSocket Protocol is running over TLS.) The server MUST close the connection upon receiving a frame that is not masked
but what's the purpose of such mask? If using Wireshark I'm reading the message the client sent without any problem?