15 Most Famous Codes, Keys, and Ciphers

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During ancient times, to send secret messages, people commonly used several codes and ciphers. This particularly helped to avoid eavesdropping and hide the messages from discreet messengers. In specific, the senders will encrypt and send messages which will later be decrypted by the receivers using a key. Even in the current digital world, modern systems use several cryptography algorithms to enhance data privacy and security. In this blog, let us see some famous codes, keys, and ciphers that are ancient.

Before we understand how texts have been encrypted in the past, first, let us learn what a code and cipher means.

What is a Code and Cipher?

Codes and ciphers are commonly used to disguise the writing of a message or text. In a code, you must transform each word in a message into a code word or symbol. In contrast, a cipher requires changing every letter in a message to a cipher letter or a symbol. Remember, when most people say “code,” they mean ciphers.

Ancient people typically encrypted messages using mathematics or arithmetic patterns. Moreover, to understand the encoded old documents and languages, you will need to apply decoding and deciphering techniques. The most well-known example is the Rosetta stone from Ancient Egypt. Even now, some ancient codes and ciphers are kept hidden.

Know How People Encrypted Messages in the Past

Famous Codes

Since ancient times, people have been using ciphers or codes to protect their secrets from outsiders in a cat-and-mouse game between those who create codes and those who break them. Text encrypting methods are as different as our imaginative thoughts. But, there aren’t many practical applications for each type of encryption. Moreover, to send secret messages, people also have used certain cryptographic devices.

Most importantly, to maintain secrecy, the cryptography techniques for message encoding and decoding should be strictly secure and difficult for outsiders to find out. Continue reading to understand how people have sent hidden messages in the past using various ciphers.

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List of Famous Codes, Keys, and Ciphers

For thousands of years, with the help of different ciphers and codes, people have hidden secret messages. Here, let us take a look at some most famous codes, keys, and ciphers used during the ancient period.

Scytale Cipher

Scytale or Skytale is a device that primarily performs a transposition cipher. It contains a cylinder with a strip of parchment twisted around it on which a message will be written. Moreover, it is said that during military campaigns, the ancient Greeks and Spartans used Scytale Cipher for secret communication.

Particularly, to read the message, the recipients will have to wrap the paper around a rod of the same diameter. Error resistance and speed are the two major benefits of Skytale ciphers. However, this cipher is easily breakable.

The Great Paris Cipher

It is another famous cipher. The Great Paris Cipher contained 1400 numbers, which either represented words or coded phrases that meant other words to increase the code’s intricacy. Moreover, Napoleon frequently used this cipher for sharing secret messages.

Caesar Cipher

The Caesar Cipher or a Shift Cipher is one of the oldest and simplest forms of message encryption. Julius Caesar used this cipher for his military communication. Hence it got the name the Caesar Cipher. Furthermore, to hide their messages, Roman legions also used this cipher.

Specifically, Caesar Cipher uses a letter substitution by another one further in the alphabet. All you have to do is shift each alphabet letter to the right or left by a predetermined amount of letters. Even though we can crack this code while we sleep, it took ancient codebreakers 800 years to find out how to do so, and another nearly 800 years to devise an even more advanced technique.

Flag Semaphore

Flag Semaphore is the telegraphy system. It is a kind of code that shares information at a distance through visual signals. Particularly, to give the signals, gloved hands, hand-held flags, rods, paddles, disks, or sometimes bare hands can be used.

Morse Code

It is one of the most famous codes, keys, and ciphers in history. During the 1830s, Samuel Morse, the inventor of telegraphy discovered this code. Hence, it got the name ‘Morse Code’. This code is a technique that telecommunication uses. Furthermore, it primarily encodes text characters as standardized sequences of two various signal durations known as dots and dashes or dits and dahs.

Typically, the International Morse Code encodes 26 English letters (A-Z), Arabic numerals, certain non-English letters, and a small collection of punctuation and procedural signals (prosigns). But there is no difference between upper and lowercase letters. Each Morse code symbol contains dots and dashes. The dot duration is the fundamental unit of time measurement in Morse code transmission.

The Enigma Code

It is an advanced cipher that Germans used during World War II. One can generate this code by using the Enigma machine that looks similar to a typewriter. When you press a letter, this machine will flash up the cipher letter on the screen.

Knowing the original wheel layout of an Enigma device was essential to decipher the messages from them as they were all similar. Yet another complicated issue was that you could begin to spin each wheel after inserting the predetermined number of characters. Therefore, the cipher would always change inside a message.

Public Key Cryptography

This is one of the best ciphers accessible today and it comes in several variations. During the 1970s, mainly, to protect the privacy of an individual, the ‘Public Key’ was introduced. This global cipher commonly uses two keys: a public key and a private key.

The public key is a large integer that is accessible to anyone. The public key plays a vital role in encrypting communication, but the private key is essential for decryption. When you transfer personal information to the bank or a machine scans your bank card, all the details will be encrypted. Later, the bank will decrypt it using its private key.


In 1990, the CIA built a sculpture on the grounds of its Langley headquarters with a difficult four-part code to tease own analysts. Thus far, it has solved only three out of the four components.

Sherlock’s Code

Sherlock Holmes finds that the information transmission uses a simple substitution cipher. In it, for each letter representation, the same dancing man was consistently used. Moreover, he uses frequency analysis as his approach to message interpretation.

Alberti’s Disk

Architect Leon Battista Alberti described an unusual device in 1467. It was a disk with two concentric rings, one with an alphabet carved in conventional form on the outside and the other with the same alphabet inscribed in reverse on the inside. Simply by rotating the inner ring and matching letters across the disk, a fiendishly complex message could be deciphered, one letter at a time.

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Pigpen Cipher

It is a geometric simple substitution cipher that replaces letters with grid fragments. This cipher is thought to be an ancient cipher that originated with the Hebrew rabbis. During the Christian Crusades, Thompson claims that “there is evidence that suggests the Knights Templar utilized a pig-pen cipher.”

According to Parrangan & Parrangan, it was used in the 16th century by a person, possibly a Mason to store his notes.

In 1531, Cornelius Agrippa described an early variant of the Rosicrucian cipher as an attribute to an existing Jewish Kabbalistic tradition. As this system was referred to by later writers, the Hebrew script was used instead of the Latin alphabet in “The Kabbalah of the Nine Chambers”. Mainly, it was used for religious symbolism rather than being used for any obvious cryptological purpose.

The Vigenere Square

This 16th-century cipher creates many Caesar shifts within a single message by using a keyword. Although it was easy to use, this coding technique was known as “le chiffre indéchiffrable” or the undecipherable cipher, because it resisted all attempts to crack it for more than 300 years.


A language takes on a secret code of its own when its readers are exterminated. That is what occurred with the ancient Egypt’s hieroglyphs. For centuries, linguists have experienced a dilemma by these stunning and recognizable characters. However, Napoleon’s army unearthed the Rosetta Stone, which made it possible for scholars to correlate the hieroglyphs with recognized Greek words.

This discovery provided the key to deciphering the language and customs of one of the greatest civilizations in history.

The Voynich Manuscript

A text with drawings written in an unidentified script and language is known as the Voynich Manuscript. Italian antiquarian book dealer Wilfrid Voynich developed this cryptic paper in 1912.

Over the years, many researchers have tried to decrypt the paper, but they haven’t been successful.  Still, scientists, linguists, and cryptologists all struggle to understand the Voynich Manuscript’s language and content.

The RSA Encryption Method

For most of human history, ciphers required the coder and the decoder to utilize the same key. But in the 1970s, researchers at the Massachusetts Institute of Technology found a way to encrypt messages safely without giving away the key beforehand.

The vast majority of modern electronic communications use public-key encryption. You might not be able to crack it, but if you could, you would be the owner of practically everything on the internet.


So far, in this blog post, we have seen 15 famous codes, keys, and ciphers. There are still many more ciphers and codes. If you would like to know more about cryptographic algorithms and encryption techniques, contact us right away.

Jacob Smith Education Reading Time: 8 minutes

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