<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div><blockquote type="cite" class=""><div class=""><br class="">On Aug 8, 2015, at 12:36 PM, Alec Muffett <<a href="mailto:alecm@fb.com" class="">alecm@fb.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">9) appending a credit-card-like “you typed this properly” extra few characters checksum over the length might be helpful (10..15 bits?) - ideally this might help round-up the count of characters to a full field, eg: XXX in this?</div><div class=""><br class=""></div><div class=""><div class="" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><pre class="" style="padding: 0px; margin-top: 0px; margin-bottom: 0px; font-size: 13.3333330154419px; widows: 1;"> a1uik-0w1gm-fq3i5-ievxd-m9ceu-27e88-g6o7p-e0rff-dw9jm-ntwkd-sdXXX.onion</pre></div><br class="Apple-interchange-newline"></div></div></blockquote></div><br class=""><div class=""><br class=""></div><div class="">For the avoidance of doubt: I am not proposing use of special-case capital letters for checksums. I merely use capital letters for emphasis. </div><div class=""><br class=""></div><div class=""><div class="">—</div><div class="">Alec Muffett</div><div class="">Security Infrastructure</div><div class="">Facebook Engineering</div><div class="">London</div></div><div class=""><br class=""></div></body></html>