For thousands of years, people have used cryptography to send secret messages. It involves turning important information into coded text so that only the intended person can understand it. During the World Wars, these codes were widely used to send critical information safely over long distances.
At the same time, another field called cryptanalysis developed to break these codes. It is like an ongoing battle between code makers and code breakers. Sometimes the code breakers succeed, and other times the code makers stay one step ahead.
I’m presenting a few of the most mysterious and famous codes and texts that remain unsolved and are still being studied today.
Table of Contents
11. The Somerton Man (Tamam Shud)
The Somerton Man case is a famous unsolved mystery about an unidentified man who was found dead on Somerton Beach in Glenelg, South Australia, on December 1, 1948.
Police discovered a small piece of paper in the man’s pocket with the words “Tamam Shud,” a Persian phrase meaning “ended” or “finished.” Later, investigators found that the paper had been torn from a copy of Rubaiyat of Omar Khayyam.
After the copy of the book was found, investigators carefully studied a series of mysterious letters written on its last pages. However, the analysis did not reveal any clear meaning.
Update: This mystery has now been solved. The unidentified man was later identified as Carl Webb, an electrical engineer.
Researchers traced his identity using genealogical DNA analysis, comparing DNA extracted from the man’s preserved hair with public genealogy databases. The identification was announced in 2022 by researchers from the University of Adelaide, particularly by Professor Derek Abbott, who had studied the case for many years.
10. Zodiac Killer’s Code
The ‘Zodiac’ was a mysterious serial killer who terrorized Northern California between the late 1960s and 1970s. There are nearly 37 killings in his name, mostly in San Francisco Bay, the cities of Benicia and Vallejo.
He shot two high school students on December 20, 1968. A year later, the local newspapers received an anonymous letter from the killer in which he took full credit for the murders. The letter contained a 408-symbol cryptogram that hid the killer’s identity.
The publishers received another letter after a few months, but this time he addressed himself as the Zodiac. He then sent two more cryptograms, one of which was never decoded.
It was never traced, and there is no personal information about him, except his name Zodiac. The Zodiac murder case is still open in the California High Court (since 1969).
9. D’agapeyeff Cipher
Alexander D’Agapeyeff was a Russian-born English cryptographer known for his unsolved D’Agapeyeff cipher. In 1939, he published the first edition of his book Codes and Ciphers, which was an introductory book on cryptography.
At the end of the book, he included a “challenge cipher” for readers to solve. The code has never been decoded. When people later asked D’Agapeyeff how to solve it, he reportedly said that he had forgotten the method himself.
Many cryptographers and scientists believe that this code may never be solved because it contains many errors.
Alexander was considered by many to be a highly talented cryptographer, mainly because his cipher remained unsolved for more than 70 years.
8. Shugborough Inscription
The Shugborough inscription is regarded as one of the world’s top uncracked ciphertexts. It is a series of letters – O U O S V A V V between the letters D and M, engraved on an 18th-century monument in the grounds of Shugborough Hall in Staffordshire, England.
What fascinates historians and cryptographers is that the inscription is engraved just below the mirror image of Nicolas Poussin’s famous painting: The Shepherds of Arcadia.
In 1982, the authors of the book “The Holy Blood and the Holy Grail” suggested that Nicolas Poussin was a member of the Priory of Sion. They claimed that his paintings and engravings contain hidden messages of great importance.
Many other theories about his possible cipher have also been suggested, but none of them have been proven.
7. Chaocipher
Chaocipher was created in 1918 by cryptographer John F. Byrne. He claimed that the cipher was simple to use but impossible to break. Byrne was so confident about its strength that he even offered cash rewards to anyone who could successfully decode it. The Chaocipher used two simple rotating disks and was small enough to fit inside a cigar box.
In May 2010, the Byrne family donated Chaocipher-related papers to the National Cryptologic Museum in Fort Meade, Maryland, USA.
6. The Voynich Manuscript
The Voynich Manuscript is a handwritten book written in an unknown script. It is named after Wilfrid Voynich, a Polish book dealer who bought the manuscript in 1912.
Carbon dating shows that the book was created in the early 15th century (around 1404–1438), and it is believed to have originated in Northern Italy.
The book contains about 240 pages filled with many illustrations and diagrams. Over the years, several skilled code-breakers and cryptographers have tried to understand it. Although they have made some interesting discoveries, no one has been able to fully solve it yet.
5. Dorabella Cipher
The Dorabella Cipher is an encoded letter written by the British composer Edward Elgar to his friend Dora Penny. The message contains 87 symbols arranged in three lines. These symbols look like small semicircles, each pointing in one of eight different directions.
Written in 1897, the letter has never been solved. In 2007, the Elgar Society organized the Dorabella Cipher competition and offered a large prize to anyone who could solve it. Many people submitted entries, and some solutions were quite impressive, but none of them were considered convincing.
4. Linear A
Ink-witten inscriptions round the inner surface of cup
Linear A and Linear B are names given to the two scripts used in Ancient Greek civilization. Sir Arthur Evans was among the first archaeologists to discover both sets of writings in various excavations.
In the 1950s, Linear B was successfully deciphered, mainly by Michael Ventris, an English linguist and architect. After this breakthrough, researchers began studying Linear A, which came before Linear B. However, Linear A is much more complex, and scientists and cryptographers are still trying to understand it.
Linear A contains hundreds of symbols. These symbols are believed to represent syllabic sounds, ideas, and meanings, similar to how Linear B works.
Although some of the syllabic symbols look similar to those in Linear B, about 80% of the characters in Linear A are unique, which makes the script much harder to understand.
3. The Beale Cipher
The Beale Cipher comes from an 1885 pamphlet that claimed a man named Thomas J. Beale buried a secret treasure near Bedford County, Virginia. The treasure was said to include gold, silver, and jewels worth more than $64 million.
The cipher is divided into three parts. One part reportedly reveals the location of the treasure, while the others describe its contents and the names of the owners. So far, only one of the three ciphers has been solved, and the other two still remain a mystery.
Some experts believe that the Beale ciphers might actually be an elaborate hoax. Articles published in the 1980s suggested that the ciphers may not have been written in the 19th century at all.
Plus, historical records from Virginia raise serious doubts about whether Thomas J. Beale ever existed, which further adds to the mystery surrounding the story.
2. The Phaistos Disc
One side of the Phaistos Disc
The Phaistos Disc is another fascinating artifact from ancient Greek civilization. In 1908, an Italian archaeologist, Luigi Pernier, discovered a clay disc about 15 cm in diameter at Phaistos on the island of Crete. The disc contains several stamped symbols arranged across its surface.
The Phaistos Disc contains 45 different symbols. These symbols were likely made by pressing small seals into soft clay, forming a spiral pattern that moves clockwise toward the center of the disc.
After many years of study, archaeologists, historians, and cryptologists believe that the writing cannot be fully deciphered yet. More examples or references of the same symbols are needed before its meaning can be understood.
1. Kryptos
Kryptos is an encrypted sculpture placed outside the headquarters of the CIA in Langley, Virginia. Since it was installed on November 3, 1990, many people have speculated about the hidden message inside it.
The name Kryptos comes from an ancient Greek word meaning “hidden.” The sculpture contains 869 characters, including 865 letters and 4 question marks.
It is divided into four sections, and while three of them have been decoded, one part still remains unsolved, making Kryptos one of the most famous unsolved codes in the world.
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