The simplicity of the signal is refreshing: TRUE if the key is shared, FALSE if the key is shared but the signer doesn't want to explicitly say so. Elegant.
April Fools Day RFC's are a grand tradition. My favorite is "The Extension of MIME Content Types to a New Medium", RFC 1437... complete with extremely dated Dan Quayle joke. IP over Avian Carriers, RFC 2549, is a close second.
Believe it or not, there is actual IETF precedence for this:<p><a href="http://tools.ietf.org/html/rfc6189#section-11" rel="nofollow">http://tools.ietf.org/html/rfc6189#section-11</a><p>(which they really should have cited in RFC 7169)<p>When the IETF was deciding whether to standards-track ZRTP or DTLS-SRTP, one of the decision points was Phil's refusal to remove the disclosure flag from ZRTP. The committee wouldn't consider adopting ZRTP unless the disclosure flag was dropped.<p>Incidentally, this is also a case of creative patent use. Phil received a patent for some core design elements of ZRTP, then freely licensed the patent as long as you correctly implement the disclosure flag.
What a coincidence, <a href="https://tools.ietf.org" rel="nofollow">https://tools.ietf.org</a> is vulnerable by the Heartbleed attack (<a href="https://news.ycombinator.com/item?id=7548991" rel="nofollow">https://news.ycombinator.com/item?id=7548991</a>), which is enough to consider IETF private key compromised. Remember, every joke has a grain of truth.
so they've been at it since 1978. how this "tradition" have not been abandoned many years ago is beyond me.<p><a href="https://en.wikipedia.org/wiki/April_Fools%27_Day_RFC" rel="nofollow">https://en.wikipedia.org/wiki/April_Fools%27_Day_RFC</a>