I enabled mutual TLS on VirtualHere and I've noticed significant performance degradation. The client is a MacBook Pro M4 and the server is a Windows 11 machine on a Intel i7-13700K so I would not expect the overhead to be noticeable compared to unencrypted traffic but it is. We are using VirtualHere to connect to a JTAG debugger so the amount of traffic being transmitted is likely less than 1 mib per second.
When I connect with openssl s_client I see that the chosen cipher suite is:
SSL-Session:
Protocol : TLSv1.2
Cipher : ECDHE-RSA-CHACHA20-POLY1305
It shouldn't really matter though honestly what it used given the power of the CPUs on both sides.
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Im guessing its actually because JTAG is a chatty protocol over USB so lots of very small packets are sent. TLS expands the size of each packet many times when wrapping in a TLS record.