Weekly Challenge Solutions

SOLUTION to Challenge 17: Aurous Coleoptera

Congratulations to Bill Briere for solving Challenge 17 in less than an hour after I posted it! He gets one point on the Leaderboard!

If you haven’t tried your hand at solving it, read this first.

Here’s original description and ciphertext:

It’s a relatively simple one. The title Aurous Coleoptera should be the only hint you need. To win, be the first to provide the solution AND the source of the quote.

6;95:]80028†‡?2;8†]48;48(4?95*6*38*?6;:-5*-‡*);(?-;5*8*6395‡1;4876*†]46-44?95*6*38*?6;:95:*‡;2:.(‡.8(5..06-5;6‡*(8)‡0¶8

“Aurous” is a synonym for gold. “Coleoptera” is the insect order of beetles. Combine them to get “The Gold Beetle” or “The Gold Bug.”

The plaintext is: “It may well be doubted whether human ingenuity can construct an enigma of the kind which human ingenuity may not, by proper application, resolve.”

This is a quote from the character Legrand in Edgar Allan Poe’s classic short story The Gold Bug. The cipher is, of course, “The Gold Bug cipher,” a simple substitution cipher that Poe created for his story. When The Gold Bug was originally published in 1843, it helped popularize cryptography and inspired many a young codebreaker.

The solid gold bug in the story was a scarab-like beetle.

You can make your own Gold Bug cipher by using Dcode’s excellent online tool.

With CodeAWeek.com, I hope to release one cipher, puzzle, or mystery each week. Anyone can attempt to solve. The winner is the first person to send a correct solution and a description of the solve method to codemaster@codeaweek.com. Once a correct solution is e-mailed, I will publish a follow-up post, congratulating the winner and revealing the secrets of the code.

You may post questions or theories in the comments, but DO NOT POST SOLUTIONS. E-mail them to codemaster@codeaweek.com.

SOLUTION to Challenge 3: A Simple Calculation

Congratulations to Euchre Mutt for being the first person to solve Challenge 3! The puzzle remained unsolved for a whopping 134 days … a site record! … which means he is awarded 134 points on the Leaderboard.

If you haven’t tried your hand at solving it, read this first.

Here’s original description and ciphertext:

With this cipher, I hope to add a new encryption method to the playbook. If you formulate the correct hypothesis, you just might take away the prize.

Some clues:

It’s a substitution cipher.

The ciphertext is 102 characters. The plaintext solution is 34 characters.

What is 102 divided by 34, and what does that tell you?

The plaintext solution is a quote from a famous mathematician.

The ciphertext is:

LCFBPDLED HCJJKAHFF TSNIGANRK GMBHJMQCO XETSSRVLZ CFDZOWVLP JJKFSRPCK BXFIVPWJO RSLYNXFSD HRHAOKQQK IJAEPFBUI QPZ

The key to solving this cipher lies in a very simple mathematical formula. It’s so simple that you’re going to kick yourself for not figuring out.

First, number the alphabet, where A=1, B=2, C=3, etc.

Now, space the ciphertext into blocks of 3 characters and apply the following formula to each block: A+B-C

The result of that formula is one plaintext character. Apply the same formula to every block of three characters, and you’ll discover the solution.

For example, if we apply it to the first three characters “LCF” …

L+C-F=

12+3-6=9

9=I

Continue down the line to get the solution:

“In math, you’re either right or you’re wrong”

… which is a quote by NASA mathematician Katherine Johnson. Johnson was profiled in the book and film Hidden Figures.

There are a couple of hints in the challenge description, which I’ll put in bold here:

With this cipher, I hope to add a new encryption method to the playbook. If you formulate the correct hypothesis, you just might take away the prize.

You may post questions or theories in the comments, but DO NOT POST SOLUTIONS. E-mail them to codemaster@codeaweek.com.

SOLUTION to Challenge 13: Fractionating

Congratulations to Euchre Mutt for being the first person to solve Challenge 13! It remained unsolved for 45 days, which means he is awarded 45 points on the leaderboard.

If you haven’t tried your hand at solving it, read this first.

Here’s original description and ciphertext:

Today, I wanted to learn about ciphers that use fractionation. I decided on a method created by a French amateur cryptographer who spent his days in working in a customs warehouse.

Three hints:

J=I

You need to figure out the keyword and the period.

“Now Morn her rosie steps in th’ Eastern Clime, Advancing, sow’d the earth with Orient Pearle.”

And the ciphertext is:

xmwuv hnmhv hderq
tbkht newsv hnmhv
fpeks ngifq rlqv

The solution:

This puzzle uses the bifid cipher, invented by Félix Delastelle around 1901. Delastelle was a bonded warehouseman by day and an amateur cryptographer by night. The bifid cipher uses a numbered grid in a very clever way to fractionate the plaintext, making it harder to crack.

The third clue is a line from Milton’s Paradise Lost. That should help you figure out that the keyword is MILTON. Incidentally, this is the opening line from Book 5, which should lead you to a block length of 5.

The decoded text reads: “Who overcomes by force, hath overcome but half his foe, ” another quote from Paradise Lost.

You can use this online Biphid Decoder to test all this out.

You may post questions or theories in the comments, but DO NOT POST SOLUTIONS. E-mail them to codemaster@codeaweek.com.

SOLUTION to Challenge 11: The Right Type

Congratulations to Puzzling.Stackexchange user Kayzeroshort for being the first to solve Challenge 11! It took him 12 days, which means he is awarded 12 points on the Leaderboard.

I’ll reveal the secrets below, but if you haven’t tried your hand, read this first.

The ciphertext:

YGWCSD QDCHVF WCLEZJ CHCTJQ YUEOYG YSE,GY KYJXDZ KYCYEP IFKWGW
TIHOEP CHRTJR DOCRTU YGY,HB PEDWUC GWU.QD ;WRTDR BESDOY ZDMNUC
SFQDCH RKWCH. POXHQO QFYOY. YPSAYR QFYHYG Y,HGIT YGRT

The original post:

Today’s cipher is a method I created based on a known method, although it is likely that someone else thought of it before me.

I’ll give you three clues:

1. The method is a spinoff of the famous method used to encode Challenge 10.
2. The punctuation in the ciphertext encodes letters in the plaintext. (There is no punctuation in the solution.)
3. The following text is not a deciphering tool but a clue that will point you in the right direction. What came after this?
  
  3 5 7 9 N O P Q R S T U V W X Y Z
  2 4 6 8 . A B C D E F G H I J K L M

The solution, as explained* by kayzeroshort on Puzzling.Stackexchange:

The lines …

3 5 7 9 N O P Q R S T U V W X Y Z

2 4 6 8 . A B C D E F G H I J K L M

… are the characters used on an early typewriter designed by Christopher Latham Sholes. He went on to invent the first typewriter with a QWERTY keyboard layout, the same layout used on modern day computer keyboards.

That clue leads to your own computer keyboard being the codebook. Using your keyboard, you can follow the rules of the Playfair cipher to decipher the code. The grid would look like this:

QWERTYUIOP
ASDFGHJKL;
ZXCVBNM,./

The deciphered text is

T H E X A S E A N D F R E X D O M A N D B E A U T Y W I T H W H I C H T H I S M A C H I N E W O R K S I S T R U L Y W O N D E R F U L E V E R Y T H I N G N O W S E E M S T O M E A S P E R F E C T A S I T C A N B E M A D E A N D I F E X L N O I N S P I R A T I O N T O A ; T E R A N Y T H I N G F U R T H E R

or

THE EASE AND FREEDOM AND BEAUTY WITH WHICH THIS MACHINE WORKS IS TRULY WONDERFUL. EVERYTHING NOW SEEMS TO ME AS PERFECT AS IT CAN BE MADE AND I FEEL NO INSPIRATION TO ALTER ANYTHING FURTHER.

As with the Playfair cipher, to get the final deciphered text from the raw decipher, replace X’s with the previous letter.

The plaintext is an excerpt from an 1870 letter by Christopher Latham Sholes about his new typewriter. It was some of the first text ever written on the QWERTY typewriter.

The puzzle title THE RIGHT TYPE is a hint alluding to “typewriter.”

* lightly edited by me.

With CodeAWeek.com, I hope to release one cipher, puzzle, or mystery every week. Anyone can attempt to solve. The winner is the first person to send a correct solution and a description of the solve method to codemaster@codeaweek.com. Once a correct solution is e-mailed, I will publish a follow-up post, congratulating the winner and revealing the secrets of the code.

You may post questions or theories in the comments, but DO NOT POST SOLUTIONS. E-mail them to codemaster@codeaweek.com.

SOLUTION to Challenge 10: No Cheating

Congratulations to Stackexchange user M Oehm, who was the first to solve NO CHEATING. It took him one day, which means he is awarded 1 point on the Leaderboard.

I’ll reveal the secrets below, but if you haven’t tried your hand, read this first.

The ciphertext:

WXYCNW LAHWNZ WONSNI LEXAPE OSMWOW RCSRQC AZ

And the original puzzle description:

Today’s cipher is a famous cryptographic method known for its economy, ingenuity, and difficulty in cracking. Its inventor created all sorts of cool things, including musical instruments, a timepiece especially useful at the North Pole, and the earliest ancestor of the Oculus Rift. Aside from this cipher, which does not bear his name, he is most famous for co-inventing a means of communicating at long distances.

The key to unlocking the mystery is his name. Good luck!

The solution:

The title “NO CHEATING” was meant to lead you to the Playfair cipher, created by Charles Wheatstone in 1854. He invented all sorts of cool things, including the English Concertina, the Polar Clock, the Stereoscope. He co-invented telegraphy, a means of communicating at long distances.

The key is CHARLESWHEATSTONE. You make a 5 by 5 square and fill it with the letters of the alphabet, starting with the key. This gives the following square:

C H A R L
E S W T O
N B D F G
I K M P Q
U V X Y Z

Since our square only has 25 spaces, we must do away with one letter. In this case, that letter was J.

We follow the rules of the Playfair Cipher to get the message:

AM UR DE RH AS GU ST BE EN CO MX IT TE DA TS AL TH IL LX

If we take out the padded Xs and convert the G* to a J, we get the fully decoded message:

“A murder has just been committed at Salt Hill.”

… which is the first line of an early telegraph that helped catch a murderer. It was the first arrest ever made using the technology.

* Usually J is encoded is I, but I made a mistake and coded it as G here.

You may post questions or theories in the comments, but DO NOT POST SOLUTIONS. E-mail them to codemaster@codeaweek.com.

SOLUTION to Challenge 9: The Collection

Congratulations to Puzzling.Stackexchange user Eedrah for solving Challenge 9 on 2017-10-21. It took him 13 days, which means he is awarded 13 points on the Leaderboard.

I’ll reveal the secrets below, but if you haven’t tried your hand, read this first.

So what’s the deal with this strange message from my Coca Cola obsessed uncle?

In the original puzzle, I mentioned my uncle’s desk had an empty Coke can on it. That was the biggest clue. This message is actually a modern-day scytale, a ribbon of ciphertext that you wrap around a cylinder to see the plaintext.

Your first step is printing the message at full size. Make sure the “1 inch” scale actually measures 1 inch. The vertical black lines indicate that you need to cut the message into five strips. The black tabs at the bottom indicate that you need to tape all the strips together.

But what size cylinder?

A 12-ounce soda can, of course!

But that would be too easy. So I reordered the 5 strips and place white boxes in the black tabs, which I hoped would be a clue that you need to write a code word there.

But what word? The cipher’s only numbers provide a clue. 18658. Or: May 8, 1886. This was the day Coca Cola first went on sale, and the first place to sell it was Jacob’s Pharmacy in Atlanta, Georgia.

And thus, the codeword is JACOB. You write JACOB in the five tabs …

then cut the strips …

… and then reorder the tabs alphabetically: ABCJO.

Now when you tape them together and wrap the ribbon around the can, you get a message!

“The new and popular soda fountain drink containing the properties of the wonderful coca plant and the famous cola nuts .”

This is a line from an early Coca Cola ad, back when the drink contained cocaine.

In the original description, I mentioned that the desk also contained pencils, a spiral notebook, a cloth tape measure, Scotch tape, and a pair of scissors. These items are clues. You need a pencil to write the codeword, scissors to cut the note into strips, and Scotch tape to tape them together. “Spiral notebook” hinted that you had to make a spiral, and “cloth tape measure” hinted that you needed to wrap something around something else.

Full disclosure: I’m not a Coke fan. My soda of choice is Diet Dr. Pepper!

——————————————————-

You may post questions or theories in the comments, but DO NOT POST SOLUTIONS. E-mail them to codemaster@codeaweek.com.

SOLUTION to Challenge 8: The Cardboard Box

Congratulations to Puzzling.Stackexchange user Neremanth for solving Challenge 8 on September 30 at 0:45 UTC. They solved the challenge 21 minutes after I reposted it on Puzzling.Stackexchange! For this, Neremanth is awarded one point.

I’ll reveal the secrets below, but if you haven’t tried your hand, read this first.

The goal was to decode this ciphertext:

SOMRF XCIAJ QELYQ DWFHU GQVMJ SOMTP NZKQB

…using this poem:

A clerk gave me a cardboard box
that now I give it to you
It once held t-shirts, jeans, and socks
It now holds one left shoe
Take out the shoe and put it on
then head to liquor store
Now drink the whiskey till it’s gone
and then drink thirteen more
Pack my box with liquor jugs,
five dozen — all in all
Checkout with clerks and give them hugs
and then go have a ball
Don’t wreck your car, though you are wrecked
and don’t heed every sign
Dead ends, some lead to misdirect,
save line and half a line

The solution is after the jump.

“Dead ends, some lead to misdirect,
save line and half a line”

There is a hint in these final two lines. The majority of the poem is filler. Except for the final two lines hint, only a line and a half are useful.

The useful lines are:

“Pack my box with liquor jugs,
five dozen — all in all”

Now remove the half line “all in all” and you get:

“Pack my box with liquor jugs, five dozen”

Notice anything remarkable about this?

It is a pangram.

A pangram is a sentence that contains every letter in the alphabet. The one I used is a variation of the famous pangram “Pack my box with five dozen liquor jugs.” I moved the words around to make it (almost) fit my meter.

Since a pangram contains all 26 letters in the alphabet, it makes a perfect cipher key. Removing the repeat occurrences of letters gets:

“PACKMYBOXWITHLQURJGSFVEDZN”

Line that up with the standard alphabet:

“PACKMYBOXWITHLQURJGSFVEDZN”
“ABCDEFGHIJKLMNOPQRSTUVWXYZ”

Now we can see that ciphertext P decodes to plaintext A, etc, etc.

So the code:

SOMRF XCIAJ QELYQ DWFHU GQVMJ SOMTP NZKQB

…becomes:

THEQU ICKBR OWNFO XJUMP SOVER THELA ZYDOG

When grouped into words, that becomes:

“The quick brown fox jumps over the lazy dog.”

…which is the most famous pangram in the English language.

You may post questions or theories in the comments, but DO NOT POST SOLUTIONS. E-mail them to codemaster@codeaweek.com.

Code a Week

Weekly cipher challenges

Weekly Challenge Solutions

SOLUTION to Challenge 17: Aurous Coleoptera

SOLUTION to Challenge 3: A Simple Calculation

SOLUTION to Challenge 13: Fractionating

SOLUTION to Challenge 11: The Right Type

SOLUTION to Challenge 10: No Cheating

SOLUTION to Challenge 9: The Collection

SOLUTION to Challenge 8: The Cardboard Box