History of Cryptography Timeline

(c. 1900 BCE – Present)

Cryptography is the practice of securing communication through codes and ciphers so that only intended recipients can read a message. Its history spans thousands of years, beginning with simple substitution ciphers used by ancient civilizations such as Egypt, Greece, and Rome. Over time, cryptography evolved from manual techniques like the Caesar cipher and polyalphabetic Vigenère cipher to mechanical devices such as the Enigma machine during World War II. The 20th century brought revolutionary advances with computer-based encryption, the invention of public-key cryptography (RSA), and standards like AES. Today, cryptography underpins digital security worldwide, protecting everything from online banking to private messaging, while researchers look ahead to quantum-resistant algorithms. More Less

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Medieval and Renaissance

Substitution ciphers used by early medieval English scribes

800 AD - 1100 AD

In early medieval England between the years 800–1100, substitution ciphers were frequently used by scribes as a playful and clever way to encipher notes, solutions to riddles, and colophons.

Kama Sutra commentaries detail substitution ciphers

1000 AD - 1300 AD

Later commentaries on the Kama Sutra offer detailed instructions for substitution ciphers, but these were composed between the tenth and thirteenth centuries AD.

Ibn Adlan's contribution on sample size for frequency analysis

1187 AD - 1268 AD

An important contribution of Ibn Adlan (1187–1268) was on sample size for use of frequency analysis, advancing the science of cryptanalysis in the medieval Islamic world.

Ibn al-Durayhim writes on cryptography

1312 AD - 1361 AD

Information about cryptology was attributed to Ibn al-Durayhim who lived from AD 1312 to 1361, but whose writings on cryptography have been lost.

Al-Qalqashandi writes Subh al-a 'sha encyclopedia

1355 AD - 1418 AD

Ahmad al-Qalqashandi (AD 1355–1418) wrote the Subh al-a 'sha, a 14-volume encyclopedia which included a section on cryptology, preserving important cryptographic knowledge.

Image source: Al-Qalqashandi

Alberti explains the polyalphabetic cipher

1467 AD

The polyalphabetic cipher was most clearly explained by Leon Battista Alberti around AD 1467, for which he was called the 'father of Western cryptology'.

Image source: Leon Battista Alberti

Cryptography emerges in Japan

1510 AD

Cryptography in Japan seems not to have been used until about 1510, and advanced techniques were not known until after the opening of the country to the West beginning in the 1860s.

Bellaso describes the cipher later known as Vigenère

1553 AD

Giovan Battista Bellaso in 1553 first described the cipher that would become known in the 19th century as the Vigenère cipher, misattributed to Blaise de Vigenère.

Image source: Giovan Battista Bellaso

Rossignol family creates the Great Cipher of Louis XIV

1600 AD

The chief cryptographer of King Louis XIV of France was Antoine Rossignol; he and his family created what is known as the Great Cipher because it remained unsolved from its initial use until 1890.

Image source: Rossignols

Modern Computing

Kerckhoffs' cryptographic writings

1880 AD - 1900 AD

Understanding of cryptography at this time typically consisted of hard-won rules of thumb; see, for example, Auguste Kerckhoffs' cryptographic writings in the latter 19th century.

Image source: Kerckhoffs's principle

Bazeries solves the Great Cipher

1890 AD

The Great Cipher remained unsolved from its initial use until 1890, when French military cryptanalyst Étienne Bazeries finally solved it.

Image source: Étienne Bazeries

Bazeries decrypts Man in the Iron Mask message

1900 AD

An encrypted message from the time of the Man in the Iron Mask (decrypted just prior to 1900 by Étienne Bazeries) has shed some, regrettably non-definitive, light on the identity of that real, if legendary and unfortunate, prisoner.

Image source: Man in the Iron Mask

Vernam proposes teleprinter cipher

1917 AD

In 1917, Gilbert Vernam proposed a teleprinter cipher in which a previously prepared key, kept on paper tape, is combined character by character with the plaintext message to produce the cyphertext.

Image source: Gilbert Vernam

Shannon's cryptography paper published

1949 AD

This article was written in 1945 and was eventually published in the Bell System Technical Journal in 1949, laying theoretical foundations for modern cryptography.

Image source: Claude Shannon

GCHQ develops classified public key schemes

1960 AD - 1974 AD

Various classified papers were written at GCHQ during the 1960s and 1970s which eventually led to schemes essentially identical to RSA encryption and to Diffie–Hellman key exchange in 1973 and 1974.

Image source: GCHQ

DES concerns raised over 56-bit key size

1976 AD

Regardless of DES' inherent quality, the DES key size (56-bits) was thought to be too small by some even in 1976, perhaps most publicly by Whitfield Diffie.

Image source: Data Encryption Standard

Diffie and Hellman announce public key cryptography

1976 AD

The second development, in 1976, was perhaps even more important, for it fundamentally changed the way cryptosystems might work. Asymmetric key cryptography and Diffie–Hellman key exchange were publicly announced by Diffie and Hellman in 1976.

Image source: Diffie–Hellman key exchange

Diffie and Hellman announce public key cryptography

RSA algorithm invented

1977 AD

The best known of the public key / private key algorithms, usually called the RSA algorithm, was invented by Ron Rivest, Adi Shamir and Len Adelman in 1977; all seem to have been independently developed at a UK intelligence agency before the public announcement.

Image source: RSA (cryptosystem)

DES published as Federal Information Processing Standard

Jan 1977

After advice and modification by the NSA, acting behind the scenes, DES was adopted and published as a Federal Information Processing Standard Publication in 1977 (currently at FIPS 46-3). It had earlier appeared in the Federal Register on 17 March 1975.

Internet commerce drives encryption standards

1990 AD

Beginning around 1990, the use of the Internet for commercial purposes and the introduction of commercial transactions over the Internet called for a widespread standard for encryption.

Zimmermann releases PGP

1991 AD

He wrote and then in 1991 released PGP (Pretty Good Privacy), a very high quality crypto system that brought strong encryption to the general public.

US export restrictions on cryptography lifted

1996 AD

Until 1996 export from the U.S. of strong encryption technology was heavily restricted, shaping the global availability of cryptographic tools.

Image source: Export of cryptography from the United States

EFF brute-force attack cracks DES in 56 hours

1997 AD

DES' 56-bit key-size has been shown insufficient against brute force attacks; one such attack, undertaken by the cyber civil-rights group Electronic Frontier Foundation in 1997, succeeded in 56 hours, rendering straight DES insecure for new designs.

PGP becomes open Internet standard

1998 AD

PGP even eventually became an open Internet standard (RFC 2440 or OpenPGP), cementing its role in widespread encrypted communications.

NIST announces AES as DES replacement

2001 AD

The aging DES was officially replaced by the Advanced Encryption Standard (AES) in 2001 when NIST announced FIPS 197.

Image source: Advanced Encryption Standard

Freeh calls for new laws against public encryption

2004 AD

As recently as 2004, former FBI Director Louis Freeh, testifying before the 9/11 Commission, called for new laws against public use of encryption.

Image source: Louis Freeh

World War Era

Mata Hari execution involves cryptography misuse

1917 AD

Cryptography, and its misuse, were involved in the execution of Mata Hari and in Dreyfus' conviction and imprisonment, both in the early 20th century.

Image source: Mata Hari

Mata Hari execution involves cryptography misuse

German Foreign Office adopts the one-time pad

1919 AD

The German Foreign Office began to use the one-time pad in 1919; some of this traffic was read in World War II partly as the result of recovery of key material in South America discarded without sufficient care by a German courier.

Image source: One-time pad

Rejewski breaks German Army Enigma

Dec 1932

Mathematician Marian Rejewski, at Poland's Cipher Bureau, in December 1932 deduced the detailed structure of the German Army Enigma, using mathematics and limited documentation supplied by Captain Gustave Bertrand of French military intelligence acquired from a German clerk.

Image source: Marian Rejewski

Polish Cipher Bureau shares Enigma secrets with Allies

Jul 25, 1939

As the Poles' resources became strained by German changes and war loomed, the Cipher Bureau, on the Polish General Staff's instructions, on 25 July 1939 at Warsaw initiated French and British intelligence representatives into the secrets of Enigma decryption.

Cipher Bureau personnel evacuate Poland

Sep 17, 1939

Soon after the invasion of Poland by Germany on 1 September 1939, key Cipher Bureau personnel were evacuated southeastward; on 17 September, as the Soviet Union attacked Poland from the East, they crossed into Romania.

Image source: Invasion of Poland

SIS breaks Japanese Purple cipher

1940 AD

A US Army group, the SIS, managed to break the highest security Japanese diplomatic cipher system (an electromechanical stepping switch machine called Purple by the Americans) in 1940, before the attack on Pearl Harbor.

Image source: Type B Cipher Machine

Ultra intelligence prompts British code changes

Jun 1943

It was only Ultra intelligence that finally persuaded the admiralty to change their codes in June 1943.

Image source: Ultra (cryptography)

British officials ordered to keep Enigma secret

Apr 19, 1945

At the end of the War, on 19 April 1945, Britain's highest level civilian and military officials were told that they could never reveal that the German Enigma cipher had been broken because it would give the defeated enemy the chance to say they 'were not well and fairly beaten'.

Image source: Cryptanalysis of the Enigma

VIC cipher used by Soviet spy ring

1957 AD

The VIC cipher (used at least until 1957 in connection with Rudolf Abel's NY spy ring) was a very complex hand cipher, claimed to be the most complicated known to have been used by the Soviets, according to David Kahn.

Image source: VIC cipher

Key Facts

The earliest known use of cryptography dates back to around 1900 BCE, when non-standard hieroglyphs were carved into an Egyptian tomb at Menet Khufu.
Julius Caesar popularized the Caesar cipher around 58 BCE, a substitution cipher that shifted letters of the alphabet by a fixed number of positions.
The Enigma machine, used by Nazi Germany during World War II, was famously broken by Allied codebreakers including Alan Turing at Bletchley Park, significantly shortening the war.
In 1976, Whitfield Diffie and Martin Hellman introduced public-key cryptography, enabling secure communication without sharing a secret key in advance; RSA followed shortly after in 1977.
Modern cryptography relies on computational hardness assumptions, and the rise of quantum computing has spurred the development of post-quantum cryptographic algorithms to protect future communications.

Source

This History of Cryptography timeline was generated with the help of AI, using information found on the internet.

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