History of Cryptography

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Cryptography Timeline

This timeline is provided courtesy of XRamp Inc.. This section is not available under the GNU Free Documentation License. Explicit permission from XRamp is required to use this information.


3500 B.C. - The Sumerians

The Sumerians develop cuneiform writing and the Egyptions develop Hieroglyphic writing.

Sumerian Cuneiform is the oldest known written language in human history and was not deciphered until the nineteenth century AD.

The earliest known form comes from Uruk, which took the form of 'word-pictures' drawn with a stylus on tablets of damp clay. Each word-picture represented an object. The word-pictures from Uruk developed into the new script now called cuneiform. The pictures gradually became 'ideographs', an object also meaning an 'idea'. Then came 'phonograms' representing sounds as well as the meaning of a picture.

Hieroglyphs are unlike Sumerian Cuneiform in that it is much more obscure. It was once thought that Egyptian Hieroglyphs were religious and historical, but recent developments could point to an economical purpose for the script.

The Sumerians develop cuneiform writing and the Egyptions develop Hieroglyphic writing
A 3" x 2" Mesopotamian tablet

1500 B.C. - Mesopotamia

A 3" x 2" Mesopotamian tablet contained an enciphered formula for making pottery glaze.

Cuneiform signs were used in the least common syllabic values to attempt to hide secrets of the formula.

About Cuneiform: Pictograms, or drawings representing actual things, were the basis for cuneiform writing. Early pictograms resembled the objects they represented, but through repeated use over time they began to look simpler, even abstract. These marks eventually became wedge-shaped ("cuneiform"), and could convey sounds or abstract concepts.

1900 BC Egypt

The first known incidence of cryptography. A scribe used nonstandard hieroglyphs in an inscription.

About Hieroglyphs: From the greek meaning "sacred writing", this is the picture language that was used most often to decorate temples and monuments. It could be written with pen and ink on papyrus, painted or carved into stone. It was carefully drawn to make the signs as accurate as possible.

Hieroglyphs were used to write the ancient Egyption lanauge. In the beginning hieroglyphic signs were used to keep records of the king's possessions. Scribes could easily make these records by drawing a picture of a cow or a boat followed by a number. But as the language became more complex more pictures were needed. Eventually the language consisted of more than 750 individual signs.

500 - 600 B.C. - ATBASH Cipher

Hebrew scribes writing down the book of Jeremiah used a reverse-alphabet simple substitution cipher known as the ATBASH cipher.

Many names of people and places are believed to have been deliberately obscured in the Hebrew Bible using this cipher.

The ATBASH cipher is a Hebrew code which substitutes the first letter of the alphabet for the last and the second letter for the second last, and so on. This cipher is one of the few used in the Hebrew language. The cipher itself, ATBASH, is very similar to the substitution cipher. A substitution cipher is one where each letter of the alphabet actually represents another letter. In the case of the Atbash cipher, the first letter of the alphabet is substituted for the last, the second for the second last and so on." I.e., for us in English the letter A becomes "Z", the letter "B" becomes "Y", the letter C becomes X, and so on.

ATBASH gets it's name from the fact that in the cipher, A becomes T, B becomes Sh, and so on, hence ATBSh - ATBASH.

Julius Caesar
1000 - Frequency Analysis

486 B.C. - Greek Skytale

Ancient Greeks invented the “skytale” (rhymes with Italy), which was a stick wrapped with narrow strips of papyrus, leather, or parchment.

The message was written on the wrapping; then the strip was removed and passed to the messenger. Only if the receiver had the same size tube would they be able to read the message.

From indirect evidence, the scytale was first mentioned by the Greek poet Archilochus who lived in the 7th century BC. Other Greek and Roman writers during the following centuries also mentioned it, but it was not until Apollonius of Rhodes (middle of the 3rd century BC) that a clear indication of its use as a cryptographic device appeared. A description of how it operated is not known from before PlutarchMestrius Plutarch (c. 120) was a Greek historian/ biographer and essayist. Born in the small town of Chaeronea, in the Greek region known as Boeotia, probably during the reign of the Roman Emperor Claudius, Mestrius Plutarch travelled widely in the Medite (50-120 AD):.

50 - 60 B.C. - Julius Caesar

Julius Caesar's simple substitution cipher.

This type of encryption is one of the simplest and most widely known encryption techniques. Each letter of the plaintext is replaced by a letter some fixed number of positions further down the alphabet. For example, a shift of 4 would move A to E, B to F, etc.

Such as:

Plain:  abcdefghijklmnopqrstuvwxyz

The Caesar cipher is named after Julius Caesar, who, according to Suetonius, used it with a shift of three to protect messages of military significance.

1000 - Frequency Analysis

Frequency Analysis leading to techniques for breaking monoalphabetic substitution ciphers: most likely motivated due to textual analysis of the Koran.

It has been suggested that close textual study of the Qur'an first brought to light that Arabic has a characteristic letter frequency. Its use spread, and was so widely used by European states by the Renaissance that several schemes were invented by cryptographers to defeat it. These included homophones, polyalphabetic substitution and polygraphic substitution schemes.

Frequency analysis is based on the fact that in any given stretch of a language, letters and combinations of letters occur with varying frequencies. In the English language for example, E is the most common letter, while X is rare.

Leon Alberti
Vigenere Cipher
Mary Queen of Scots

1466 - Leon Alberti

Leon Alberti invented the cipher disk and cryptographic key. Alberti's cipherdisk was polyalphabetic, meaning that a new alphabet could be created each time by turning the disk.

This type of disk was the only method of using this type of cipher until the 16th century.

Alberti thought his cipher was unbreakable. This assumption was based on his inquiries into frequency analysis, which is the most effective method of deciphering monoalphabetic cryptograms. Given enough cryptotext, one can use the frequency of the letters in reference to a normal distribution to find the shift and solve the cryptogram. This system fails to solve polyalphabetic cryptograms, however, since the letter distribution is garbled.

1587 - Vigenere Cipher

The Vigenere Cipher is polyalphabetic, meaning that instead of there being a one-to-one relationship between each letter and its substitute, there is a one-to-many relationship between each letter and its substitutes.

The encipherer chooses a keyword and repeats it until it matches the length of the plaintext, for example, the keyword "XRAMP":


1587 - Mary Queen of Scots

Mary Queen of Scots was beheaded for plotting against Queen Elizabeth using mono-alphabetic substitution ciphers. Mary was condemned on the basis of evidence obtained from enciphered messages cracked by Tomas Phelippes.

Phelippes was able to crack a cipher used by Mary and conspirators who wanted to place her on the English throne, even though the cipher contained nulls and codewords.

The Telegraph
Samuel Morse
Zimmerman Telegram

1753 - The Telegraph Invented

The Telegraph showed that electrostatically generated signals which stood for letters of the alphabet could be sent a long way through a wire with the circuit being completed through the Earth.

The original telegraph used 26 wires; one for each letter of the alphabet.

1820 - Beale Cipher

A Set of three cipher texts:

  • One allegedly stating the location of a buried treasure of gold and silver estimated to be worth over $20 Million
  • One describing the content of the treasure
  • And one listing the names of the finders' next of kin.

1845 - Morse Code

Samuel Morse creates Morse code: Morse code represents letters, numbers and punctuation marks by means of a code signal sent intermittently. This is an early form of digital communication. It uses to states(on and off) composed into five symbols: dit('), dah(-), short gap (between letters), medium gap (between words) and long gap (between sentences).

Morse code differed from the telegraph in the fact that it sent code for each letter on a single wire rather than a wire for each letter.

In 1863, the European form of Morse code was created.

1863 - Kasiski breaks Vigenere Cipher

Prussian major named Kasiski proposed a method for breaking a Vigenere cipher that consisted of finding the length of the keyword and then dividing the message into that many simple substitution cryptograms.

Frequency analysis could then be used to solve the resulting simple substitutions.

1883 - Auguste Kerckhoff

Auguste Kerckhoff is best known for a series of two essay she published in 1883 in the Journal of Military Science. These articles surveyed the state of the art in military cryptography and included many pieces of advice and rules of thumb, including his famous six principals of practical cipher design.

The most well known is the second of his six principals, otherwise known as Kerckhoffs' principle or Kerckhoff's Law. This law states that "There is no secrecy in the algorithm - It is all in the key.".

1917 - Zimmerman Telegram

The Zimmerman telegram was a secret telegram which included proposalsfor a German alliance with Mexico. The telegram was intercepted and decrypted by the British Government.

The Enigma
Caption Midnight

1918 - ADFGVX Cipher

The German ADFGVX cipher was the first cipher used by the German Army during World War I. This was a fractioning transposition cipher which combined a modified Polybius square with a single columnar transposition used to encode a 36 letter alphabet (26 letters plus 10 digits).

1918 - The Enigma

Arthur Scherbius designed the Enigma - a device which allowed businesses to communicate confidential documents without having to resort to clumsy and slow codebooks.

The device consisted of many rotors turning on a common axis. The rotors had numbers 1 through 26 marked on the edge, or the alphabet A-Z, and were equipped with 26 electrical contacts (one for each letter of the alphabet) so that when a letter was pressed, the output would depend on the position of the rotor and its cross wiring.

Within the same year, the Enigma was put to use; most famously by Nazi Germany before and during WWII.

1937 - 1945 WWII

The Navajo Code Talkers have been credited with saving countless lives and hastening the end of the war.

The Code Talker's primary job was to talk and transmit information on tactics, troop movements, orders and other vital battlefield information via telegraphs and radios in their native dialect. A major advantage of the code talker system was its speed. The method of using Morse code often took hours where as, the Navajos handled a message in minutes. It has been said that if was not for the Navajo Code Talker's, the Marines would have never taken Iwo Jima.

The Navajo's unwritten language was understood by fewer than 30 non-Navajo's at the time of WWII. The size and complexity of the language made the code extremely difficult to comprehend, much less decipher. It was not until 1968 that the code became declassified by the US Government.

1940 - Captain Midnight

The Captain Midnight radio show featured the "Code-O-Graph" at the end of each transmission.

Fans could write into one of the program's sponsors to get the Code-O-Graph and then decode the secret messages from the program.

This is a classic example of a cipher disk except that it used numbers instead of letters.

Claude Shannon
John Walker
British Intelligence inventors of PKC

1949 - Claude Shannon

Claude Shannon published a paper on his Unicity Concept.

The Unicity Concept measures the least amount of plaintext which can be uniquely deciphered from the corresponding ciphertext, given unbounded resouces by the attacker.

1968 - John Walker

US Navy - The start of John Walker's 17 year espionage of copying keys and sending them to the Soviets. It is estimated that he helped the Soviet Union garner more than one million messages and compromised US codes.

British Intelligence inventors of PKC

James Ellis, Clifford Cocks, Malcolm Williamson stated as the original inventors of public key cryptography. This fact was originally kept secret until after 1976 when Diffie and Hellman take credit for discovering PKC.

Horst Feistel
The Orange Book

1971 - Lucifer

Horst Feistel created Lucifer at IBM's Thomas J. Watson Laboratory.

Lucifer was the name given to several of the earliest civilian block ciphers and was a direct precursor to the Data Encryption Standard.

1973 - Bell-LaPadula

David Bell and Len LaPadula create the Bell-LaPadula Security Policy Model in response to US Airforce converns over the security of time sharing mainframe systems.

The Bell-LaPadula model is a formal state transition model of computer security that describes a set of access control rules.

A system is defined as "secure" when all access controls are in accordance with a specific security policy.

1975 - Cryptographic hash of passwords

Hash algorythms are typically used to provide a digital fingerprint of a file's contents to ensure that the file has not been altered by an intruder or virus. They generally help to preserve the integrity of a file.

1976 - Diffie & Hellman

Whitfield Diffie & Martin Hellman publish Public-key Cryptography.

This asymmetric key cryptosystem was known as the Diffie-Hellman key exchange, and was the first published practical method for establishing a secret key through unprotected communications channels without a prior shared secret.

1980's - US Navy

During this time, US Navy ships would sail with a forklift full of NSA distributed keys printed on paper tape or punch cards.

1983 - Orange Book

The Department of Defense published "Trusted Computer System Evaluation Criteria" otherwise known as the "Orange Book". The Orange Book was the benchmark for systems produced almost two decades later, and Orange Book classifications such as C2 provide a shorthand for the base level of security features of modern operating systems.

1987 - Clark-Wilson Model

Based on transactions, the Clark-Wilson model is used for systems where integrity is enforced across both the Operating System and the application.

The Clark-Wilson model extended to cover separation of duty in 1993.

1987 - Rivest Cipher 4

Ronald Rivest creates RC4, or "Rivest Cipher 4".

RC4 generates a pseudorandom stream of bits which for encryption, is combined with plaintext using XOR. To generate the keystream, the cipher makes use of a secret internal state containing a permutation of all 256 bites and two 8 bit index pointers. The permutation is initialized with a variable length key and generated using PRGA.

1988 - Kerberos

Kerberos is invented at MIT.

Kerberos is a network authentication protocol designed to provide strong authentication for client/server applications by using secret key cryptography.

1989 - Chinese Wall Model

The Chinese Wall model combines commercial discretion with legally enforceable mandatory controls required in the operation of many financial services.

The Chinese Wall policy states that people are only allowed access to information which is not held to conflict with any other information that they may already posses.

1991 - PGP

Zimmermann publishes PGP. Originally created in response to US Senate Bill 266 which was designed to force manufacturers of secure communications to provide a "back door" by which the US Goverment would be able to read those communications. The bill was ultimately defeated.

1994 - American Escrowed Encryption Standard

Otherwise known as the "Clipper Chip" the significant feature of EES is its so-called key escrow method of enabling eavesdropping by authorized government agencies under certain circumstances. The program was ended due to public concerns over the invasion of privacy.

1998 - Deep Crack

The Electronic Frontier Foundation used a brute force attack to crack the DES Algorithm called Deep Crack, testing 90 billion keys per second - cracking a 56 bit key in 4.5 days..

1999 - Distributed.net

Distributed.net used the same brute force concept as Deep Crack, testing 250 billion keys per second.

2004 - Louis Freeh

Former FBI Director Louis Freeh testified before the 9/11 Commission calling for new laws against the public use of encryption.

Books of Interest

External References