Secret codes have baffled and mystified people throughout human history. Ever since people first began to write down their thoughts on paper, they have used a variety of encryption techniques to disguise exactly what they were saying. The evolution of codes and ciphers is something that was necessary to keep important information hidden from people who didn’t need to know the contents of a message or document. Such methods have been used to transmit secret communications or pass on vital information to allies for centuries, with the need growing even more during times of war.
Today, the use of encryption is very much a part of our lives. Almost all of our electronic correspondence over the internet goes through some kind of security measure designed to stop people spying on what you are saying. Meanwhile, government departments such as the NSA, GCHQ and FSB all try to crack the codes that keep that information safe so they can gather intelligence and carry out their work. As methods of keeping data hidden have evolved from simple substitution ciphers to complex algorithms designed by supercomputers, it is becoming ever more difficult to crack the best examples. However, it is not just modern codes that have proved impossible to solve. Many versions from the past have proved too much of a puzzle for even the best cryptographers, ensuring that their secrets are kept locked away for decades or even centuries.
10 Voynich Manuscript
The Voynich manuscript is an illustrated hand-written book that contains a number of entries on various plants and herbs. Carbon dated to the early 15th century, it is believed to originate from Northern Italy, though it has remained a huge mystery as no one has been able to decipher the writing, including professional codebreakers and cryptologists from government agencies. It is written almost entirely in an unknown form of writing, with the words appearing to match no language from the time. The contents of the manuscript are destined to remain a mystery unless someone can solve the code to the writing.
9 Chinese Gold Bar Cipher
The Chinese Gold Bar Ciphers are a group of cryptograms that appear on several gold bars that are alleged to have been issued to a Chinese general in 1933. The disputed claim states that these were given to the general for him to redeem at a bank deposit in the United States, with the value possibly totaling up to $300 million. Experts have used a variety of techniques to try to decode the cryptograms and shed light on this dispute with little success over the past 80 years, leaving those in possession of the bars with no way of redeeming their money.
LCS35 is a time capsule puzzle that was created by Ron Rivest in 1999. Located at MIT, anyone who solves it gets a prize that is hidden away inside an accompanying lead lined box, giving plenty of incentive to try to break the code. The only problem is that it is likely to take 35 years to unravel, thanks to the fact that it uses a complicated mathematical problem to hide the solution, requiring powerful computers to carry out the calculations rather than a tradition cryptogram method. Of course, significant advances in technology could allow sophisticated machines to carry out the necessary calculations quicker.
7 Zodiac Killer Cryptograms
The Zodiac Killer has perhaps become more well-known not for the brutal killings that he carried out, but for the series of clues that he left behind in the form of cryptograms. Out of the four largest ciphers he sent to police and newspapers in long letters, only one has been definitively solved, while the others have not yet revealed their secrets, which could possibly include the killer’s name. The cryptic messages were largely believed to be a way for the killer to taunt police, though some believe the codes may not be able to be solved as the murderer may have made errors.
6 Beale Ciphers
The Beal Ciphers gained prominence because they would apparently reveal the location of a significant amount of treasure that had been hidden once solved. This has led to a great number of people trying to decode the three texts that make up the document, including information about the treasure, where it is located and who should inherit it when it is discovered. So far, only one piece has been fully deciphered with the other two keeping their secrets hidden, though some believe they may actually be a hoax.
5 D'Agapeyeff Cipher
In 1939, Alexander D’Agapeyeff wrote a book called Codes and Ciphers, including a challenge cipher at the back of the book for readers to try to solve using techniques learned in the preceding pages. Known as the D'Agapeyeff cipher, it has confounded cryptographers and codebreakers ever since. What the author described as a modest code designed simply to test the reader’s knowledge gained from the book has proved impossible to crack, even by professional codebreakers and cryptographers. To make matters worse, the author himself later forgot what encryption he had used, preventing him from revealing exactly what method he had utilized.
4 Dorabella Cipher
A handwritten code created by the noted composer Edward Elgar, the Dorabella Cipher has remained unsolved since 1897, with even the woman it was sent to having no idea what it meant or how to decode it. Many theories have been suggested, including that the symbols are part of a substitution cipher or even a melody, with the different parts representing particular notes. Dora Penny, the recipient of the note, was unclear why Elgar had sent it to her and stated that he had never sent any similar letters to her.
Kryptos is a sculpture outside of the Central Intelligence Agency headquarters in Virginia. It was created by Jim Sanborn and contains four separate encrypted messages, three of which have been solved since its dedication in 1990. However, the fourth and final code has still not been cracked despite its notoriety and the clues given out by Sanborn. Considering that the CIA and NSA have themselves even worked on the puzzle and that it has been around for more than 25 years, it seems like more clues may be necessary to fully understand the code.
2 The Phaistos Disk
This archeological find was originally discovered in Crete in 1903, and has since baffled scientists and experts. Archeologists agree that the gold disc is likely to date from around 1700-1600 B.C., though they are unable to make any sense of the script that is engraved on the surface. The 45 different symbols that make up the text are widely considered to be some sort of code, though no one has been able to decipher it since its discovery. Many believe this isn’t even possible due to the limited amount of data to work from.
1 Somerton Man Codes
The Somerton Man, sometimes known as the Taman Shud Case, was an incident that eventually revealed a secret code that no one has been able to crack. An unidentified man was found on a beach in Southern Australian in 1948 along with a scrap of paper that turned out to belong to a book. When the book was later found it contained phone numbers and a cipher that has still not been solved, shrouding the entire affair in mystery.