The Zodiac 340 Cipher has been finally cracked, after 51 long years. Decades passed by, but this particular cipher continued to puzzle sleuths. Puzzle solvers and mathematicians never gave up because of the intellectual challenge, while authorities were at it hoping it would provide information on who The Zodiac Killer actually was.
In the late 1960s, the Zodiac Killer terrorised the Bay Area, who committed at least five murders but claimed that the number was 37 in total. Like most serial killers, the Zodiac Killer had a lust for attention. He wrote letters to the authorities and newspapers bragging about his murders, which he called his work. To prove the authenticity of the claims, the letters included unreleased details and evidence from the crime scenes. Such was the character of the killer that we still don’t know to date if all his murders happened within California, or whether his gruesome killing spree had spread to Nevada at some point too.
In August 1969, following the murders of three of the five known victims, the Zodiac Killer sent three letters which were almost identical to three Bay Area newspapers. Each letter also included one-third of a 408-symbol cryptogram that the suspect said would reveal his identity. The Killer demanded the papers publish the letters in full or he would kill again. The first coded letter he wrote was cracked quickly by a school teacher. It appears that this did not settle well in his deranged mind, and he - quite literally - made an unbreakable code.
The message was sent in November 1969 to the San Francisco Chronicle newspaper by the alleged serial killer. Its code consists of a series of cryptic letters and symbols. Rumours flew that the letter carried the identity of the infamous killer. While it did not provide any personal information about the killer, it did reveal his irrationalities and convoluted mind.
Ever since the letter was received, both professional and amateur cryptographers have worked on this puzzle. The name 340 is given due to the presence of 340 characters spread throughout in 17 columns.
The code was cracked by a trio: David Oranchak, a 46-year-old American web designer - who started working on the cipher in 2006 - Sam Blake, an Australian mathematician, and Jarl Van Eykcke, a Belgian logistician.
Now, the question arises, how? How did the trio solve a cipher that stumped cryptographers over the last 50 years? Oranchak has revealed that the reason why this text was so difficult is that it uses multiple encryption techniques. It has to be first broken down into three irregular sections, then a transposition algorithm is to be applied followed by the substitution of the symbols. Truly complex! The way the trio realised this was truly magical. Using Jarl Van Eykcke’s decryption software-“AZDecrypt”, they were able to figure out the correct decryption technique.
Most ciphers used today by computers rely on mathematics to scramble messages. Transposition ciphers, by contrast, are largely relics from the past that use rules to rearrange the characters or groups of characters in the message.
The cipher is first divided into three sections as shown in the image below:
Transposition ciphers rearrange messages in a wide variety of ways. A common way is by rearranging columns of a message. The message in the 340 was rearranged by manipulating triangular sections cut from messages written into rectangles, as shown in the image.
After this rearrangement of the symbols, the symbols are replaced by the alphabets according to this key -
After all these steps are done, the cipher is decrypted and translates into this
“I HOPE YOU ARE HAVING LOTS OF FUN IN TRYING TO CATCH ME THAT WASN’T ME ON THE TV SHOW WHICH BRINGS UP A POINT ABOUT ME I AM NOT AFRAID OF THE GAS CHAMBER BECAUSE IT WILL SEND ME TO PARADICE ALL THE SOONER BECAUSE I NOW HAVE ENOUGH SLAVES TO WORK FOR ME WHERE EVERYONE ELSE HAS NOTHING WHEN THEY REACH PARADICE SO THEY ARE AFRAID OF DEATH I AM NOT AFRAID BECAUSE I KNOW THAT MY NEW LIFE WILL BE AN EASY ONE IN PARADICE DEATH”
Over a span of half a century, several professionals and cryptologists have attempted to solve this, but none came close. In the following paragraphs, I describe how these three individuals solved a problem that had persisted for so long and had shown no signs of even being solvable.
The coded letter was divided into three parts as each part was sent to a different newspaper company. So it seemed almost certain that the three would be encrypted in the same way, but have to be solved separately. This was true and supported by most of the cryptologists who worked on this over the years.
Now the key was discovered when the cryptographers saw the appearance of letters of words such as “PARADICE” and “DEATH” next to each other. These two words were used frequently in his other letters and coded texts. Using this, the trio formed a list of possible keys.
The last and most decisive part was the rearrangement of the symbols. After spending time with the zodiac cipher, it was evident that alongside a key substitution, a transposition also needed to take place. With the variable key, the number of rearrangements to be made was not possible to perform without some kind of software. This is why they used Jarl Van Eykcke’s decryption software-“AZDecrypt”. They computed millions of the possible combinations, and while the software was doing the job, Dave saw one combination with visible short statements with the usage of the words “PARADICE” and “DEATH”. He, with the other two, then started on creating a few plausible solutions and ran them through AZdecrypt. One of them yielded a pretty satisfactory result. With some fixing to remove a few errors in the encrypted text….they had finally achieved the impossible! They cracked it and finally unravelled the mystery of the zodiac cipher and brought to light all of its information.
The Zodiac cipher was a puzzle which no one had perhaps realistically hoped to ever solve, but David Oranchak’s persistence and his work with his two partners eventually paid off; it finally brought to an end a search which has been going on since the 1960s.
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