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<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br></div>Hi Brian,<div><br></div><div>I think the IANA registry actually has the key length specified as part of the suite enumeration.</div><div><br></div><div>Examples are:</div><div><br></div><div><span class="Apple-style-span" style="font-family: -webkit-sans-serif; font-size: 13px; "></span></div><div><span class="Apple-style-span" style="border-collapse: collapse; font-family: -webkit-sans-serif; font-size: 13px; -webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px; ">TLS_RSA_WITH_AES_128_CBC_SHA256</span></div><div><font class="Apple-style-span" face="-webkit-sans-serif" size="3"><span class="Apple-style-span" style="border-collapse: collapse; font-size: 13px; -webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px;">TLS_RSA_WITH_AES_256_CBC_SHA256</span></font></div><div><font class="Apple-style-span" face="-webkit-sans-serif" size="3"><span class="Apple-style-span" style="border-collapse: collapse; font-size: 13px; -webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px;"><br></span></font></div><div><font class="Apple-style-span" face="-webkit-sans-serif" size="3"><span class="Apple-style-span" style="border-collapse: collapse; font-size: 13px; -webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px;">There are other suites that don't specify numeric key sizes, but in these cases, the algorithm itself</span></font></div><div><font class="Apple-style-span" face="-webkit-sans-serif" size="3"><span class="Apple-style-span" style="border-collapse: collapse; font-size: 13px; -webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px;">(3DES for example) work with a specific key size that doesn't vary.</span></font></div><div><font class="Apple-style-span" face="-webkit-sans-serif" size="3"><span class="Apple-style-span" style="border-collapse: collapse; font-size: 13px; -webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px;"><br></span></font></div><div><font class="Apple-style-span" face="-webkit-sans-serif" size="3"><span class="Apple-style-span" style="border-collapse: collapse; font-size: 13px; -webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px;">In this case, we may be able to just specify that we're talking about a minimum suite, with a reference to RFC 5246 and</span></font></div><div><font class="Apple-style-span" face="-webkit-sans-serif" size="3"><span class="Apple-style-span" style="border-collapse: collapse; font-size: 13px; -webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px;">the IANA registry itself.</span></font></div><div><font class="Apple-style-span" face="-webkit-sans-serif" size="3"><span class="Apple-style-span" style="border-collapse: collapse; font-size: 13px; -webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px;"><br></span></font></div><div><font class="Apple-style-span" face="-webkit-sans-serif" size="3"><span class="Apple-style-span" style="border-collapse: collapse; font-size: 13px; -webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px;">Randy</span></font></div><div><font class="Apple-style-span" face="-webkit-sans-serif" size="3"><span class="Apple-style-span" style="border-collapse: collapse; font-size: 13px; -webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px;"><br></span></font></div><div><font class="Apple-style-span" face="-webkit-sans-serif" size="3"><span class="Apple-style-span" style="border-collapse: collapse; font-size: 13px; -webkit-border-horizontal-spacing: 2px; -webkit-border-vertical-spacing: 2px;"><br></span></font></div><div><span class="Apple-style-span" style="font-family: -webkit-sans-serif; font-size: 13px; "></span><div><div>On Jan 30, 2009, at 6:26 PM, Brian Smithson wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>I am still wondering how these two attributes can be used in practice. I<br>know that we can uniquely identify cipher suites using the IANA<br>registry, but is there an authoritative source to specify that one suite<br>is "more minimum" than another? And if you consider different key<br>lengths that might be acceptable for a given suite, then can we really<br>say that suite X is more minimum than suite Y even if an HCD supports a<br>relatively long key length for X but only supports a relatively short<br>one for Y?<br><br>-- <br>Regards,<br>Brian Smithson<br>PM, Security Research<br>PMP, CISSP, CISA, ISO 27000 PA<br>Advanced Imaging and Network Technologies<br>Ricoh Americas Corporation<br>(408)346-4435<br><br><br></div></blockquote></div><br></div></body></html>