Designing Compelling Worm Sanctuaries/Investigation/QR code
This page lists the numbers found by decoding the Worm book QR code.
Decodes to following:
FNAIU + AJTEM 1 KPWLC 2 UKTUN 3 STYKK 4 RVRXQ 5 MQMSO 6 SWKLX 7 KHMNK 8 HSDCJ 9 NWMDI 0 MGADN # JAVWL * CWKUX A CQNOG B XKVRK C RJVYO D MHCDJ E OMZNP F ETTSJ G UYLAF H ZSYLC I WOJWG J GQJTJ K KYUKE L JARXW M YRSVQ N MCFBJ O CDGVL P PWHML Q MSABD R JSTMP S DFXGL T DABCE U HMJSI V UREYG W KYGRF X JVYFC Y BCUUA Z SMJCS E GCJVD E YPBIE E
This looks like a simple substitution cipher, with each 5-gram corresponding to a letter, number, or +.
The reason there are multiple encodings for "E" to defeat a frequency count. "E" is the commonest letter in the English language. If you're decrypting a simple substitution cipher (one encoding for each letter) you just count the appearances of each encoding. You assume that the most common encoding in the message represents E. The next most common is probably T. Then you start looking at the patterns in the words, guessing new substitutions, until you have the whole message.
One way to make this harder is to provide multiple encodings for common letters (E in this case). Instead of MHCDJ being the most common group in the encrypted message, the hits for "E" will be evenly split across four different groups: MCDHJ, SMJCS, GCJVD, and YPBIE. That means that the attacker is going to see "DFXGL" (representing "T") as the most common group. The attacker will think "DFXGL" is actually "E" and everything will go haywire.
Because we already have the key, we don't need to attack. This is just an example of attention to detail by the PMs.
Note: When scanned the QR Code also displays 'Metadata: L'.
QR code from sofia/green/worms book is the same: http://prntscr.com/1qtxjz http://imgur.com/o3cFzY2 http://forums.unfiction.com/forums/viewtopic.php?p=1014161#1014161