Egyptians used alternate hieroglyphs while inscribing tablets, the first documented use of written cryptography. The place was Menet Khufu, which borders the Nile River. The writer of these tablets did not use a completely different set of hieroglyphs, though. Instead, his was a system of partial substitution, with some unusual hieroglyphs here and there.
To hide messages, generals in ancient Greece used the shaved head of a servant, tattooed the message on his bald scalp, waited a week, and then sent the servant on his way. The secret message was concealed under a fresh growth of hair.
The Arabs were the first to make significant advances in cryptanalysis (the practice of changing ciphertext into plaintext without complete knowledge of the cipher).
Abu Yahmadi, creator of the first Arab dictionary, wrote a book in 725 on how he solved a Byzantine cryptographic puzzle written in Greek. His method of attack started on an assumption that the puzzle began with "In the name of god," and so he worked out the rest from that assumption. This method of attack is the same one that was employed in World War II to break German communications.
Subhalasha, an Arabic Encyclopedia (1412), contained a section on Cryptography. Ciphers cited are substitution and transposition. Also, it mentioned running a text through multiple substitution ciphers.
In the famous Greek drama the Iliad, cryptography was used when Bellerophon was sent to the king with a secret tablet which told the king to have him put to death. The king tried to kill him by having him fight several mythical creatures, but he won every battle.
The first major advances in cryptography were made in Italy. Venice created an elaborate organization in 1452 with the sole purpose of dealing with cryptography. They had three cipher secretaries who solved and created ciphers that were used by the government.
But during the Spanish Inquisition epoch the cryptography was doomed and persecuted being considered black magic and Satanic deed.
But during the Spanish Inquisition epoch the cryptography was doomed and persecuted being considered black magic and Satanic deed. In the period of Renaissance the creativity in many spheres also gave impulse to cryptography as a science and as an art of secret communications between the monarchs and emperors, like Leonardo da Vinci, Cardinal Richelieu and the Kings of France Louis XII-XIV. The «coding of messages», the substitution of words and figures by symbols and numerals of previously agreed character became wisely used in government correspondence. And the services of specialists in coding and decoding of secret letters became available as a result of this practice.
The Kama Sutra of Vatsayana lists cryptography as the 44th and 45th of 64 arts (yogas) men and women should know and practice. The date of this work is unclear but is believed to be between the first and fourth centuries, AD. In this list of arts, the 44th and 45th read: The art of understanding writing in cipher, and the writing of words in a peculiar way; The art of speaking by changing the forms of words. It is of various kinds. Some speak by changing the beginning and end of words, others by adding unnecessary letters between every syllable of a word, and so on.
The Equatorie of the Planetis (1392), possibly written by Geoffrey Chaucer, contains passages in cipher. The cipher is a simple substitution with a cipher alphabet consisting of letters, digits and symbols. Breaking codes can make or break historical figures. A good example of how codes can change history, is the story of Mary Queen of Scots, a Catholic who was chased out of an th Century. Mary fled to England looking for increasingly Protestant Scotland in the 16protection from her cousin Elizabeth, the queen of England, but instead she received 19 years in prison. Sir Francis Walsingham, Elizabeth's principal secretary suspected that Mary was actively involved with a man called Anthony Babington to overthrow Elizabeth. Walsingham intercepted messages that Mary had written to Babington in a secret cipher. Little did they know that the person helping them smuggle messages was a double agent working for Queen Elizabeth. Walsingham handed the messages over to a man called Thomas Phelippes to decode. This he eventually did, and Mary effectively signed her own death warrant. Just because we can't understand a text does not mean that it was necessarily meant to be kept secret. Sometimes it is just that we have lost the art of decoding them. The ancient Egyptians used hieroglyphs, as their means of written communication and for thousands of years this script was a mystery to scholars. In 1799, a French team discovered a slab of stone, now known as the Rosetta Stone, which is permanently housed in the British Museum. The Rosetta Stone contained three scripts, hieroglyphics at the top, demotic (the simplified form of ancient Egyptian writing) in the middle and Greek at the bottom. Over the course of many years, using the Rosetta Stone as a reference point, scholars gradually unraveled the mysteries of hieroglyphics.
The writer Edgar Allan Poe had a great fascination with cryptography. Besides numerous references to it in his stories, he conducted his own cryptographic challenge in December 1839. This challenge was published in Alexander's Weekly Messenger, and in it he asked the readers to submit their cryptographs to him, asserting that he would solve them all. He was true to his word and for the next six months, Poe managed to decipher all the codes submitted by his readers. A year later he was sent two cryptographs by one of his readers, Mr. W.B.Tyler. Poe published these cryptographs in the magazine for his readers to solve, but never published the solutions himself. Many believe that W.B.Tyler was a pseudonym for Poe himself, and that he was the author of the cryptographs, which remained unsolved for decades. The first US Patent on a cryptographic device was filed in 1861. About 1,800 patents on the field have been issued since.
In 1895, radio was invented. The importance of this to cryptology is immense. During times of War, it allowed for enemy communications to be intercepted in mass. Thus, the profession of cryptanalysis, or the breaking of encrypted messages, was born.
Gilbert S Vernam created a machine in 1917 that makes a non-repeating, virtually random sequence of characters (often called a one-time pad). Using an encryption key the same length as the message, and never using that key again is the only proven method of securely communicating. However, it is impractical under most circumstances because all parties must have a long and identical key, which presents a logistical nightmare for everyday use.
In 1918, the United States employed eight American Indians from the Choctaw tribe to relay important messages across insecure communication channels in their native tongue. Since Native American languages are extremely complex and difficult to learn, this allowed for simple and effective encryption. During World War II they repeated this trick with the Navaho code talkers.
The greatest era of international smuggling - Prohibition (in the 1920s) - created the greatest era of criminal cryptology. (To this day, the FBI runs a cryptanalytic office to deal with criminal cryptography.) During Prohibition, alcohol was transported into the country by illegal smugglers who used coded radio communication to control illegal traffic and help avoid Coast Guard patrols. In order to keep the Coast Guard in the dark, the smugglers used an intricate system of codes and ciphers. The Coast Guard hired Mrs. Elizebeth Smith Friedman to decipher these codes, and thus forced the smugglers to use more complex codes, and to change their keys more often. She succeeded in sending many of them to jail.
In 1924, Alexander von Kryha produced his «coding machine» which was used, even by the German Diplomatic Corps, into the 1950s. However, it was cryptographically weak - having a small period. A test cryptogram of 1135 characters was solved by the US cryptanalysts Friedman, Kullback, Rowlett and Sinkov in 2 hours and 41 minutes.
Nevertheless, the machine continued to be sold and used - a triumph of salesmanship and a lesson to consumers of cryptographic devices. In the 1930s, the British developed the TYPEX encryption machine, based on the commercial Enigma from the 1920s. This machine contained five rotors, each of which changed letters of the alphabet to other letters. After each character of the message being encrypted was typed, the rotors changed positions, creating an entirely new encryption scheme for the next letter. Reversing the process decrypted the message.
In 1937, the Japanese invented the PURPLE machine to encrypt messages. This machine was a totally new concept to cryptography. All machines prior to it used rotors to change the position of letters in the alphabet. Instead, the Purple Machine used telephone stepping switches, and thus standard cryptanalytic techniques were useless against it. US cryptographer William Friedman eventually broke the code generated by this machine.
The Bombe, a machine that decodes Enigma messages, was invented in 1940. The workload of (Russian) code machine operators was enormous: between 1941 and 1945 they coded and decoded more than 1,6 million messages (or 1500 telegrams in cipher per day). By the end of the war, the cryptographic service of the General Staff of the Army comprised some 5000 specialists and the amount of coding machines involved in the providing of security of telecommunications reached some 396 units.
The Lucifer cipher was developed at IBM in 1970. This eventually evolved into DES, which was accepted as the official US standard, only recently replaced by AES. DES was strengthened in the form of triple-DES, an algorithm accepted worldwide as relatively secure.
"New Directions in Cryptography" was published in 1976, introducing the concept of public-key cryptography, which forms the basis of Internet encryption. The book also focuses on the powers of authentication via a one-way function, where the authenticator does not need to know the actual password.
In 1990, mathematicians from Switzerland invented the International Data Encryption Algorithm (IDEA) to replace the aging DES. IDEA has 128 bits, meaning there are 340,282,366,920,938,463,463,374,607,431,768,211,456 possible keys. This algorithm also has the advantage of being able to be carried out quickly, because it uses math that comes naturally to computers.
In English, "e" is the most common letter, typically showing up 13 percent of the time. Code breakers look for such patterns, deducing that if a certain letter or symbol shows up more than any other, it probably stands for the letter "e."
During WW2, the neutral country Sweden had one of the most effective cryptanalysis departments in the world. It was formed in 1936, and by the time the war started, employed 22 people. The department was divided into groups, each concerned with a specific language. The Swedes were very effective in interpreting the messages of all the warring nations. They were helped, however, by bungling cryptographers. Often the messages that were received were haphazardly enciphered, or even not enciphered at all.
The Swedes even solved a German cipher that was implemented on a Siemens machine similar to a Baudot machine used to encipher wired messages. In a short story by Sir Arthur Conan Doyle, The Adventure of the Dancing Men, Sherlock Holmes is confronted by a simple substitution cipher. He solves the crime by deciphering a code in which the cipher text elements are hieroglyphics of little dancing men. Holmes figures these symbols are some kind of secret code. Using the method of frequency analysis, he substitutes the letter 'e' for the most commonly occurring figure. He also notices repetitions of certain poses, yet these dancers hold flags in their hands. Instead of counting these as different letters, he deduces that they mark word divisions. Following along these lines, and with the aid of some background knowledge of the squire's wife, he manages to crack the code and solve the case.