<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto">You are right - there’s no urgency in PQ <u>signatures</u>. <div><br></div><div>However, PQ KEM keys aren’t small. And, as I said, für austere links every unnecessary byte of crap hurts. </div><div><br></div><div>Also, sending root certs seems (marginally) useful only when the recipient is a Web browser. And even then I assume most of the IT people would want to block the ability of a “mere” user to add an “unblessed” trusted root. </div><div><br><div dir="ltr">Regards,<div>Uri</div></div><div dir="ltr"><br><blockquote type="cite">On Mar 31, 2021, at 14:15, Viktor Dukhovni <openssl-users@dukhovni.org> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><blockquote type="cite"><span>On Mar 31, 2021, at 2:01 PM, Blumenthal, Uri - 0553 - MITLL <uri@ll.mit.edu> wrote:</span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>For a Web GUI with the user at the console (e.g., a Web browser), it might be OK. </span><br></blockquote><blockquote type="cite"><span></span><br></blockquote><blockquote type="cite"><span>For my needs (devices talking to each other over austere links), sending the root CA very is both useless and wasteful. One you factor in the sizes of Post-Quantum keys and signatures - you’ll start disliking this idea even more. </span><br></blockquote><span></span><br><span>There's no urgency in post-quantum keys for CA signatures in TLS. Their</span><br><span>future weakness does not compromise today's traffic. Until actual scalable</span><br><span>QCs start cracking RSA and ECDSA in near real-time only the ephemeral key</span><br><span>agreement algorithm needs to be PQ-resistant now to future-proof session</span><br><span>confidentiality.</span><br><span></span><br><span>So certificates can continue to use RSA and ECDSA for quite some time.</span><br><span></span><br><span>-- </span><br><span> Viktor.</span><br><span></span><br></div></blockquote></div></body></html>