### Notes on Kryptos Part 4

Copy of message I sent to the Kryptos group on Yahoo! for anyone whose working on Kryptos but not in that group.

Given Elonka's notes mentioning that K4 uses a cipher system not known to anyone else I decided to investigate other possible ways of attacking K4. Specifically, I wondered if the BERLIN crib might not be as simple as NYVTT turning letter for letter into BERLIN.

First I assume that this is something that's breakable by hand as was the rest of Kryptos and thus would simply be based on MOD 26 arithmetic of letters and might involve transposition of characters.

So I went to see if there's a word that could be permuted to create some permutation of BERLIN from NYVTT. There is: it is SILENT

NYVTT
ENTSIL
-----
RLINBE

More strikingly this works if you are sliding SILENT from the start of K4, it falls in just the right position to make BERLIN

OBKRUOXOGHULBSOLIFBBWFLRVQQPRNGKSSOTWTQSJQSSEKZZWATJKLUDIAWINFBNYPVTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR
SILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTS
GJVVHHPWRLHETAZPVYTJHJYKNYBTEGYSDWBMOBBWWJKAPOMSOIENXEMLTEJBFNMRLINBEQMYHSHKQDRFENPWAOVYUNSCPOPTJ

Now leading on from this I wonder if the cipher used for K4 consists of permutations of both the key and the ciphertext. Note how BERLIN is permuted within itself and so then I returned to the start of cipher text to see if there's a permutation of SILENT that results in a word (after permutation) starting in position 0. Once again there is:

OBKRUO
ILENTS
------
WMOENG

i.e. the word is WOMEN, assuming that the G is in the word after women. In this case ILENTS is a simple rotate of the word SILENT (just as ENTSIL followed by ENTSIL gives us BERLIN). There are likely other words as well, but this one is strikingly long.

Running through all six possible rotations of SILENT you get:

OBKRUOXOGHULBSOLIFBBWFLRVQQPRNGKSSOTWTQSJQSSEKZZWATJKLUDIAWINFBNYPVTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR
SILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTS
GJVVHHPWRLHETAZPVYTJHJYKNYBTEGYSDWBMOBBWWJKAPOMSOIENXEMLTEJBFNMRLINBEQMYHSHKQDRFENPWAOVYUNSCPOPTJ

OBKRUOXOGHULBSOLIFBBWFLRVQQPRNGKSSOTWTQSJQSSEKZZWATJKLUDIAWINFBNYPVTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR
ILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSI

OBKRUOXOGHULBSOLIFBBWFLRVQQPRNGKSSOTWTQSJQSSEKZZWATJKLUDIAWINFBNYPVTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR
LENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSIL
ZFXKMWISTAMTMWBEANMFJYDZGUDIJVROFLGBHXDLBYDWRDRHHEGCCTFHVTOQYJOGQXGXGFRNAOJZVSKBGCULTKXNZCLYRDUIC

OBKRUOXOGHULBSOLIFBBWFLRVQQPRNGKSSOTWTQSJQSSEKZZWATJKLUDIAWINFBNYPVTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR
ENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILE
SODJCZBBZZCWFFHDQQFOPXTCZDJHZYKXLKWEAGJKRBWFXCHKANMBSWYQBSETRSUFGAZGMEHQTXPYLVDKMBKOMTDMPFEHXCKLV

OBKRUOXOGHULBSOLIFBBWFLRVQQPRNGKSSOTWTQSJQSSEKZZWATJKLUDIAWINFBNYPVTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR
NTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILEN
BUCZFSKHYPFPOLGTTJOUONWVIJIXCRTDKAZXJMIAUUFLWSKDJTLRVPHWAIHMAYTVJTIMLUKJCDOOOOMQLRNHVZCCSYNNWSNEE

OBKRUOXOGHULBSOLIFBBWFLRVQQPRNGKSSOTWTQSJQSSEKZZWATJKLUDIAWINFBNYPVTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR
TSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENTSILENT

If you look you'll see various words popping out (in the ILENTS set, second row above, there's WOMEN at the beginning and closer to the end an anagram of WATCH).

Perhaps there's a method to choosing which shift of SILENT to use followed by some sort of transposition.

Unknown said…
Mod26 is such a great concept for K4 given all of our difficulty in solving it. Unfortunately unless the linear arrangement of the K4 text was changed and then enciphered, we would want to see the decryption reveal the word BERLIN in order in that position exactly to be sure one was on track. You've inspired me to revisit the Hill cipher especially since I'd been feeling stuck in a rut so, thanks! -Kfan
Unknown said…
Key the Roman Numerals from the CIA wall against K4. Add QIX:

QIXXXXII

TIME FLIES

Unknown said…
what if we are looking at this from the wrong angle. like if it is corner to corner bottom left to top right but in reverse order
Unknown said…
what if we are looking at this from the wrong angle. like if it is corner to corner bottom left to top right but in reverse order

### Your last name contains invalid characters

My last name is "Graham-Cumming". But here's a typical form response when I enter it:

Does the web site have any idea how rude it is to claim that my last name contains invalid characters? Clearly not. What they actually meant is: our web site will not accept that hyphen in your last name. But do they say that? No, of course not. They decide to shove in my face the claim that there's something wrong with my name.

There's nothing wrong with my name, just as there's nothing wrong with someone whose first name is Jean-Marie, or someone whose last name is O'Reilly.

What is wrong is that way this is being handled. If the system can't cope with non-letters and spaces it needs to say that. How about the following error message:

Our system is unable to process last names that contain non-letters, please replace them with spaces.

Don't blame me for having a last name that your system doesn't like, whose fault is that? Saying "Your last name …

### All the symmetrical watch faces (and code to generate them)

If you ever look at pictures of clocks and watches in advertising they are set to roughly 10:10 which is meant to be the most attractive (smiling!) position for the hands. They are actually set to 10:09.14 if the hands are truly symmetrical. CC BY 2.0image by Shinji
I wanted to know what all the possible symmetrical watch faces are and so I wrote some code using Processing. Here's the output (there's one watch face missing, 00:00 or 12:00, because it's very boring):

The key to writing this is to figure out the relationship between the hour and minute hands when the watch face is symmetrical. In an hour the minute hand moves through 360° and the hour hand moves through 30° (12 hours are shown on the watch face and 360/12 = 30).
The core loop inside the program is this:   for (int h = 0; h <= 12; h++) {
float m = (360-30*float(h))*2/13;
int s = round(60*(m-floor(m)));
int col = h%6;
int row = floor(h/6);
draw_clock((r+f)*(2*col+1), (r+f)*(row*2+1), r, h, floor(m…

### The Elevator Button Problem

User interface design is hard. It's hard because people perceive apparently simple things very differently. For example, take a look at this interface to an elevator:

From flickr

Now imagine the following situation. You are on the third floor of this building and you wish to go to the tenth. The elevator is on the fifth floor and there's an indicator that tells you where it is. Which button do you press?

Most people probably say: "press up" since they want to go up. Not long ago I watched someone do the opposite and questioned them about their behavior. They said: "well the elevator is on the fifth floor and I am on the third, so I want it to come down to me".

Much can be learnt about the design of user interfaces by considering this, apparently, simple interface. If you think about the elevator button problem you'll find that something so simple has hidden depths. How do people learn about elevator calling? What's the right amount of informati…