Unsolved Ciphers from History's Archives

The Zodiac Killer's 340-symbol cipher remains one of the most infamous unsolved ciphers in history.

It's been over 50 years since the cipher was sent to the San Francisco Chronicle, yet no one has been able to crack the code.

The Kryptos sculpture at CIA headquarters has four encrypted messages, with only three of them solved.

The fourth message, encrypted in a 97-character sequence, remains unsolved to this day.

The cryptogram was created by artist Jim Sanborn, who has refused to reveal the solution, leaving cryptographers to try and figure it out.

Historical ciphers have been used for centuries to conceal secret messages. The Caesar Cipher, for example, was used by the ancient Romans to encrypt messages.

The Caesar Cipher is a simple substitution cipher where each letter is shifted by a fixed number of positions down the alphabet. This method was used by Julius Caesar himself to send secret messages to his generals.

One of the most famous historical ciphers is the Zodiac Killer's cipher, which was sent to the San Francisco Chronicle in the late 1960s and early 1970s. The cipher remains unsolved to this day.

The Venetian Cipher is an intriguing example of historical cryptography. It's found in a letter from Marco Otthobon to Juan Mocenigo, dated 27 April 1589.

The cipher consists of an alphabetical letter followed by Arabic figures. This type of cipher is mentioned in the same article section as the Venetian Letter.

Unfortunately, the cipher symbols were only partially deciphered by Valle de la Cerda, and his solution is now lost.

The Nicholas Throckmorton Cipher is a historical cipher that remains unsolved to this day.

In fact, it's not the only one, as we see with Ferdinand III's encrypted letters, which have never been solved.

Ferdinand III, the emperor of the Holy Roman Empire, used a secret writing system during the Thirty Years' War.

Ignatius Pollaky, a British private detective, published a number of encrypted newspaper ads that some of which have never been solved.

These examples show that even with the best efforts, some historical ciphers remain undeciphered.

The Moray-Wood Cipher is a historical cipher that has left cryptographers stumped for centuries. It was used by James Stewart, Earl of Moray and Regent of Scotland, to communicate with John Wood, Scottish ambassador in England in 1568.

The cipher is found in a letter written on July 13, 1568, in Add MS 32091 at the British Library. This letter is a significant historical document that sheds light on the diplomatic relations between Scotland and England during that time.

The cipher seems simple, but the short ciphertext has not been deciphered, leaving cryptographers to try and crack the code.

The Spanish Cipher has a rich history, with several unsolved ciphers that remain a mystery to this day.

One of the most intriguing examples is the cipher in a letter from Emperor Charles V, dated 1521, which remains unsolved.

A letter from Juan Perez, ambassador in Rome, to Emperor Charles V in 1527 also contains an unsolved cipher.

The encryption methods used by historical figures like Ferdinand III, who ruled from 1608 to 1657, have never been cracked.

The Lodovico Birago Cipher is a fascinating historical cipher that has puzzled cryptographers for centuries. Lodovico Birago wrote a letter to the Duke of Nevers in 1571, which contains a numerical cipher that remains unsolved. The letter is preserved in the BnF fr. 3251 collection.

The letter is dated 13 November 1571, and it's written in Italian. The numerical cipher is a paragraph that appears to be encoded using a specific key. Unfortunately, the key has not been reconstructed, making it impossible to decipher the message.

The cipher is part of a larger collection of letters from Lodovico Birago to the Duke of Nevers, which were written between 1570 and 1572. These letters are significant historical documents that provide insight into the lives of the nobility during the Renaissance period.

Despite the challenges of deciphering the Lodovico Birago Cipher, it remains an important historical artifact that continues to intrigue cryptographers and historians alike.

Charles I's four letters in cipher during his captivity in the Isle of Wight (1648) remain undeciphered for a long time.

In 2021, a breakthrough was made by Norbert Biermann and Matthew Brown, who solved the cipher used in two of the four letters.

Charles I's letters were a challenge to decipher due to the complexity of the cipher used.

Norbert Biermann and Matthew Brown's work on the cipher is a testament to the power of modern cryptography techniques.

The fact that two of the four letters were solved is a significant achievement, providing new insights into the history of cryptography.

During the American Revolutionary War, coded letters were used to communicate sensitive information. One such example is an encoded letter from Admiral D'Estaing to Gerard, French minister in Philadelphia, dated 30 April 1779.

The letter begins with a coded message, which has yet to be fully deciphered. The highest number used in this letter is 597, suggesting a smaller code than the diplomatic codes of the time.

A decoded, but not identified, code of Luzerne, French minister to the United States, has been presented on a blogpost.

The German Enigma Messages were a significant challenge for the Allies during World War II, with three unsolved messages intercepted in 1942. These messages were only solved much later, with two of them cracked in 2006 by Stefan Krah's M4 Message Breaking Project using distributed computing.

The Enigma cipher was notoriously difficult to break, but the Allies were eventually able to decipher it. However, these three messages from 1942 remained a mystery for over 60 years.

A photo of an unsolved Enigma message sent in 1945 by a deputy of the Supreme Commander of Upper Rhine Area is still available online. This message was sent on January 10, 1945, and its contents remain unknown.

In 2006, the Enigma @ Home project used spare CPU cycles on members' computers to try and solve the three remaining messages from 1942.

Historical ciphers have been used for centuries to conceal messages, and some of the most intriguing ones are still unsolved today.

The Enigma message is a classic example of an undeciphered cipher. In 1942, three Enigma messages were intercepted by the Allies, but they remained unsolved until 2006 when distributed computing solved two of them.

One of the unsolved Enigma messages was sent on January 10, 1945, by a deputy of the "Oberbefehlshaber Oberrhein" (Supreme Commander of Upper Rhine Area), and a photo of it is still available online.

The Enigma @ Home project attempted to solve the three leftover Enigma messages from 1942 using spare CPU cycles on members' computers.

In 1944, a member of Hitler's paramilitary organization SS sent an encrypted radio message to a recipient named Lippert, but the cleartext is still unknown today.

The Enigma message is just one of the many historical ciphers that continue to fascinate and baffle us, and it's a testament to the ingenuity and complexity of these codes.

Ferdinand III, the emperor of the Holy Roman Empire, used a secret writing system during the Thirty Years' War, but it has never been solved, and its secrets remain lost to history.

The Codex Seraphinianus is an unusual book, a beautiful artwork, and an unsolved crypto mystery. It's the Voynich Manuscript of the 20th century.

The Codex Seraphinianus is often compared to the Voynich Manuscript due to its mysterious and undeciphered nature. The Voynich Manuscript, for example, has a script unrelated to European languages and an alphabet with up to 28 characters used without punctuation throughout the text.

The Codex Seraphinianus, like the Voynich Manuscript, has been studied by code breakers, but its meaning remains unclear. Some of the world's best code breakers have been drawn to the Voynich Manuscript and been left stumped, including William and Elizebeth Friedman, a married couple and two of their generation's leading cryptanalysts.

The Codex Seraphinianus is an undeciphered code, much like the Voynich Manuscript, which has led to outlandish theories about its real meaning. One popular idea is that there's no meaning to it at all, that it was created as some kind of hoax.

The YOG'TZE Case is a fascinating and frustrating example of an unsolved cipher. In October 1984, a German food engineer named Günther Stoll died under mysterious circumstances.

Stoll's death was either a murder or an accident, but the truth was never determined. The only clue was a piece of paper with the word YOG'TZE written on it.

Stoll had written YOG'TZE just before his death, but it remains a mystery what it means. Neither the police nor the public have been able to decipher its significance.

Rapa Nui's Rongorongo is a hieroglyphic language that's been shrouded in mystery for centuries. The language was used by the Rapa Nui people on Easter Island.

The idea that knowledge of rongorongo disappeared in the 1860s due to raids by European raiders is no longer widely accepted. This narrative was cast into doubt over time.

Many artifacts containing rongorongo were destroyed, with some being burned by the Rapa Nui themselves to build fires. This was likely at the urging of Catholic missionaries who warned the natives that rongorongos were connected to their heathenism.

A few dozen inscriptions did survive, and people have been trying to decipher the symbols for over a century. Despite the efforts, no one has put forth a convincing translation of the texts.

Some glyphs appear to represent human or animal forms, while others are abstract shapes. This has led to fantastical ideas about the language's origin, including claims of aliens and lost continents.

Young Rapa Nui students of the past were able to master rongorongo in just a few months. This suggests that the language was not as complex as previously thought.

The language's origin remains contentious, with debates raging about whether it predates European contact.

Modern ciphers have made significant strides in recent years, with the development of quantum-resistant algorithms like the New Hope cipher, which was introduced in 2016. This cipher is designed to withstand attacks from quantum computers.

The New Hope cipher uses a variant of the hash function, called the "hash-based" approach, to create a secure encryption method. This approach has shown great promise in protecting sensitive information from even the most advanced cyber threats.

One notable example of a modern cipher is the AES-256 algorithm, which is widely used in secure communication protocols like HTTPS and SSH.

The MLH cryptogram is a real-life puzzle that has been unsolved for over four decades. It's a message sent by a young man from Israel to his parents in California, who reported him missing.

The MLH cryptogram is a remarkable example of a modern cipher that remains undeciphered. It's a challenge that has been ongoing for an incredibly long time.

The MLH cryptogram is not the only example of a modern cipher that has been left unsolved. There are many more out there, like the Riverbanks Ripper cryptograms, which were left behind by a serial murderer in the 1970s.

The MLH cryptogram has been a mystery for so long that it's hard to imagine what it could be. But that's what makes it so intriguing - the possibility that we might never know the answer.

The Riverbanks Ripper cryptograms are just one example of a modern cipher that has been left behind by a person with a dark secret. The Dorabella cryptogram is another example of a modern cipher that has been unsolved for over 120 years.

The MLH cryptogram is a reminder that cryptography is not just a tool for securing our online activities, but also a fascinating puzzle that can capture our imagination.

In 1916, Sun Yat-sen received an undecoded telegram in Japanese archives that was encoded with a conventional Chinese telegraph codebook.

The message was later superenciphered by adding 111 instead of using a code condenser, which may have been used by Junzaburo Yamada, who supported Sun Yat-sen.

A clue to identifying the code condenser may be found in the fact that typical Chinese codebooks at the time did not have figures in the 9000s.

In 2008, the Zhongshan Warship Museum called for solution of encrypted telegrams found in SS Zhongshan, which was sunk by the Japanese bombing in 1938.

As of 2009, 352 out of 891 telegrams were solved, leaving many still unsolved.

An encrypted message left behind by an unknown man who robbed a ticket counter at the train station of Lima, Ohio in 1916 remains unsolved to this day.

The message has been a puzzle for over a century, and its purpose remains unknown.

Ron Rivest's Timelock is a cryptographic puzzle that was designed to take 35 years to break. Ron Rivest, co-inventor of the RSA algorithm, came up with the idea in 1999.

The puzzle is an example of a verifiable delay function, which means the answer can only be solved after a certain number of steps. It's a challenging problem that requires a lot of computational power.

The problem is to compute 2^(2^t) (mod n) for specified values of t and n. This is a mathematical equation that needs to be solved.

In 1999, Ron Rivest published an encrypted text that was designed to take 35 years to break. Despite being unbroken for 18 years, it remains a mystery.

The puzzle was even solved 15 years early by a self-taught Belgian programmer named Bernard Fabrot.

The Blitz is a fascinating example of an encrypted book. The Blitz Ciphers are an alleged encrypted book found in London after World War II. Only eight page scans have been published.

Some people consider the Blitz Ciphers a fake, which raises questions about their authenticity. This highlights the ongoing debate in the cryptography community about what constitutes a genuine encrypted message.

The Blitz Ciphers are an intriguing example of an encrypted book, but their authenticity is questionable.

The Dorabella cipher is a real-life puzzle that has been stumping cryptographers for over a century. It was created by Edward Elgar in the late 1800s for his friend Dora Penny, who was 20 years his junior.

The cipher consists of 24 symbols, each made up of 1, 2, or 3 approximate semicircles oriented in one of eight directions. Mark Pitt claimed to have cracked the code using a revolving cipher and a musical cipher, but hasn't revealed the answer.

The cipher remains one of the most popular crypto mysteries in the world, with 120 years still having no solution. Many people have claimed to have cracked the code, but none have been widely declared correct.

Tim S. Roberts proposed a solution that read "P.S. Now droop beige weeds set in it—pure idiocy—one entire bed! Luigi Ccibunud lovingly tuned liuto studio two." However, his solution is questionable, as it includes arbitrary references like "Luigi CCibunud" and "liuto studio two."

In 1944, a member of Hitler's paramilitary organization SS sent an encrypted radio message to a recipient named Lippert. The cleartext is still unknown.

This message is a prime example of how encryption was used during World War II.

The SS radio message is a significant piece of history, highlighting the importance of encryption during wartime.

A similar message was sent by a deputy of "Oberbefehlshaber Oberrhein" in 1945, which remains unsolved.

Researchers have been working to break original Enigma messages from World War II, with some success.

The Kaliningrad bottle post is a fascinating example of a modern cipher. Two years ago, an encrypted message was found in Kaliningrad, Russia.

It's a cryptogram, which means it's a coded message that needs to be deciphered. Can a reader break this cryptogram and uncover the hidden message?

The Rubin cryptogram is a real-life example of a mysterious and undeciphered code.

This cryptogram was found in the possession of 18-year-old chemistry student Paul Rubin, who tragically died from cyanide poisoning in 1953.

The police investigation into Rubin's death was unable to crack the code.

The Somerton Man is a mystery that has been puzzling people for decades. He was found dead on an Adelaide beach in 1948 with no ID and his clothing labels removed.

A well-dressed man, he carried a ripped piece of paper with the Persian words Tamam Shud, which means 'it is finished'. The code was written in the Rubaiyat of Omar Khayyam, a poetry book that was not found at the crime scene.

The code in the book has never been deciphered, and it's a crucial clue in solving the mystery of Somerton Man's identity and cause of death. Authorities exhumed his body in 2021 in hopes of finding DNA evidence to reveal his identity.

A phone number for Jessie Thomson, a nurse, was found in the book, but she claimed not to know Somerton Man. Despite the efforts of investigators, the case remains unsolved.

The Kryptos puzzle is a mind-bending enigma located at the CIA's Langley, Virginia HQ. It's a 12-foot copper statue that displays a collection of random letters, but it's actually a riddle for the ages.

Only three of the four passages have been decrypted, and the codemaker has provided several clues to cryptologists over the years. The sculpture was created by artist Jim Sanborn and installed on Langley's grounds in 1990.

The first section of code was cracked, revealing a poetic sentence written by Sanborn: "Between subtle shading and the absence of light lies the nuance of iqlusion." Sanborn intentionally misspelled the word "illusion" to "mix it up."

The second section is a rather opaque paragraph that references Langley's coordinates and former CIA head William Webster. The third section paraphrases Howard Carter's account of discovering King Tut's tomb in 1922.

Sanborn has said that the first three sections provide a clue to solving the fourth section, and he's also decoded a few specific words from its text, including Berlin, clock, and northeast.