50 Fun Facts About Cryptography

Suetonius says Julius Caesar guarded military messages by shifting each letter how many places?

Three places, A becoming D, is the shift Suetonius records for Caesar; the same idea survives online as ROT13, which shifts by thirteen.

The word cryptography pairs an ancient root for 'writing' with one meaning what?

Hidden is the sense of kryptos, the root that opens the word, so cryptography literally means hidden writing; the CIA's Kryptos sculpture borrows the same root.

Which scholar announced in Paris in 1822 that he could read the Egyptian scripts on the Rosetta Stone?

Jean-François Champollion showed that hieroglyphs spelled sounds as well as pictures, a trick the stone's Demotic text had already revealed for foreign names in 1802.

Which German engineer's firm patented the rotor cipher machine in 1918 that went on sale as Enigma?

Arthur Scherbius co-founded Scherbius & Ritter, which patented the design in 1918 and began selling the finished machine under the Enigma name in 1923.

When Enigma went on sale in 1923, which buyers was the machine first aimed at?

Commercial firms were the first target: the machine was pitched to businesses wanting to shield telegrams from rivals, and only later did the German armed forces adopt and modify it.

Because of its reflector, an Enigma machine could never encrypt a letter as what?

Itself was the one output Enigma could never give a pressed key, a patented side-effect of the reflector that Allied codebreakers learned to exploit.

Bletchley Park, bought by MI6's chief with his own money in 1938, lies in which English county?

Buckinghamshire's Bletchley, now inside Milton Keynes, got the codebreakers because Admiral Hugh Sinclair paid £6,000 of his own money when the government said it had no budget.

Churchill called Bletchley Park's staff 'the geese that laid the golden eggs' and never did what?

Cackled is the word: the codebreakers kept quiet for decades, and many families never learned that a parent had done secret war work.

Eight soldiers of which tribe used their language on Army phones in the 1918 Meuse-Argonne fighting?

Choctaw men of the 36th Infantry Division were among the first code talkers, a generation before the Marines recruited Navajo speakers for the Pacific.

Which Los Angeles city civil engineer proposed the Navajo language to the Marines in World War II?

Philip Johnston pitched the idea at the start of the war, and the first 29 Navajo recruits began boot camp in May 1942.

In the Zimmermann Telegram of January 1917, Germany proposed a wartime alliance with which country?

Mexico was offered German help to recover Texas, Arizona and New Mexico, and the telegram's publication helped push the United States into the war in April 1917.

Which Admiralty codebreaking section, named for its office, decoded the Zimmermann Telegram?

Room 40's Nigel de Grey had partly decoded the message by the next day, in what is called Britain's greatest intelligence triumph of the First World War.

Deciphered letters from the 1586 Babington Plot led to whose execution in 1587?

Mary, Queen of Scots replied in cipher on 17 July 1586 endorsing the killing of Elizabeth I, and that decoded reply became the evidence that sent her to the block.

The Vigenère cipher, once called 'indecipherable', was first described in 1553 by which Italian?

Giovan Battista Bellaso laid out the key-word system in his 1553 book, but 19th-century writers pinned it on the French diplomat Blaise de Vigenère, and the wrong name stuck.

Which Prussian infantry officer published the first general attack on the Vigenère cipher in 1863?

Friedrich Kasiski's 95-page book of 1863 ended three centuries of the cipher's 'unbreakable' reputation, though Charles Babbage had quietly broken a version around 1854 without publishing.

Atbash reverses an alphabet end to end; its name comes from four letters of which alphabet?

Hebrew's Aleph, Taw, Bet and Shin spell the name, and the Book of Jeremiah uses the trick to disguise Babylon as 'Sheshach'.

Spartan commanders read a scytale message by winding its strip of parchment around what?

A rod of exactly the same diameter as the sender's lines the letters up again; Plutarch gave the earliest surviving description of the device.

Which 9th-century Baghdad scholar first described breaking ciphers by counting letter frequencies?

Al-Kindi's Manuscript on Deciphering Cryptographic Messages introduced frequency analysis, building on the work of al-Khalil, and counts as the birth of cryptanalysis.

Which Renaissance architect's 1467 cipher disk was one of the first polyalphabetic ciphers?

Leon Battista Alberti's device, two concentric disks on a pin that could be turned mid-message, changed the substitution alphabet as it went.

In 1952 architect Michael Ventris showed that Linear B tablets held an early form of which language?

Greek in its Mycenaean form is what the tablets hold, centuries older than Homer; Ventris died in a car crash in 1956, weeks before his book on the script appeared.

The only solved Beale cipher, describing treasure buried in Virginia, used which document as its key?

Declaration of Independence word numbers unlock the second of three ciphertexts printed in an 1885 pamphlet; the two naming the spot and the owners remain unsolved.

Because it is the most common letter in English, which letter is a single dot in Morse code?

E got the shortest code because Alfred Vail sized each symbol to letter frequency, which he estimated by counting the type in a Morristown printer's cases.

Which 1906 international distress call was picked as a simple Morse rhythm, not as an abbreviation?

SOS never stood for 'save our souls'; German maritime rules adopted it in 1905, the 1906 convention made it worldwide, and it stayed the radio distress signal until 1999.

Which AT&T engineer invented the 1917 teleprinter cipher that became the unbreakable one-time pad?

Gilbert Vernam's patent was granted in 1919, but Army captain Joseph Mauborgne added the rule that made it unbreakable: a truly random key used only once.

In which year did Whitfield Diffie and Martin Hellman publish the first open account of public keys?

1976 is when the pair published the earliest public work proposing a private key with a matching public key; Ralph Merkle is credited beside them as an inventor on the patent.

Ron Rivest and Adi Shamir share the initials of RSA with which third MIT colleague from 1977?

Leonard Adleman was the mathematician whose job was to find weaknesses in the functions Rivest and Shamir proposed, until Rivest's sleepless night after Passover 1977 produced one Adleman could not break.

Which Secretary of State axed the Cipher Bureau in 1929 with 'Gentlemen do not read each other's mail'?

Henry Stimson was reportedly most offended when Herbert Yardley boasted he could read all the Vatican's traffic; Yardley's 1931 tell-all The American Black Chamber followed.

In 'The Adventure of the Dancing Men', a stick figure holding what marks the end of a word?

A flag in a figure's hand ends a word, a rule Sherlock Holmes spots in the 1903 story after Norfolk squire Hilton Cubitt brings him the scrawled messages.

In whose 1843 story 'The Gold-Bug' does William Legrand decode a cipher to find buried treasure?

Edgar Allan Poe won the Philadelphia Dollar Newspaper's $100 prize with the story, probably the largest single sum he ever earned for a piece of writing.

Which French officer cracked Louis XIV's Great Cipher around 1893 by spotting it encoded syllables?

Étienne Bazeries took three years over the task, reading messages the Rossignol family had enciphered for the Sun King two centuries earlier.

The Playfair cipher, the first to encrypt letters in pairs, was invented in 1854 by which scientist?

Charles Wheatstone devised it for telegraph secrecy, but his friend Lord Playfair promoted it so energetically that the cipher took Playfair's name.

Which French lieutenant broke the German ADFGVX cipher in June 1918, falling ill from the strain?

Georges Painvin cracked the cipher, which had gained its sixth letter V that very month, and the effort left him physically ill.

Which colour codename did US codebreakers give Japan's Type B diplomatic cipher machine in 1940?

Purple's stepping-switch machine was rebuilt by William Friedman's Army team in September 1940 without anyone having seen the original, and its decrypts were codenamed Magic.

To prove 'AF' meant Midway in 1942, US codebreakers had the island radio a fake breakdown of what?

Its water plant was the bait: Joseph Rochefort's Station Hypo team had the order sent by undersea cable, and the shortage then surfaced in Japanese traffic under the 'AF' label.

Which Founding Father's wheel cipher of 36 lettered disks was reinvented as the US Army's M-94?

Thomas Jefferson's design lay forgotten until 1922, by which time the Army had already arrived at the M-94 on its own and put it into service.

In the Culper spy ring's number code, George Washington himself was assigned which number?

711 stood for Washington in the code used by the ring he and Benjamin Tallmadge organised in 1778 to watch the British in occupied New York City.

The pigpen cipher, which turns letters into grid fragments, is often named for which fraternal order?

Freemasons used it so often from the early 18th century, for lodge records and even tombstone engravings, that it is frequently called the Freemason's cipher.

Which English statesman devised a 1605 cipher that hides a message in the choice between two typefaces?

Francis Bacon's method turns every letter into a five-symbol pattern of As and Bs, then prints an innocent cover text in two typefaces to carry it.

Which composer sent a friend the still-unsolved Dorabella Cipher of 87 symbols in 1897?

Edward Elgar wrote the three lines of squiggles to Dora Penny, who never worked out what they said, and nobody has convincingly read them since.

The 2008 white paper that invented Bitcoin was published under which name?

Satoshi Nakamoto released the open-source software in January 2009, and the currency's smallest unit, one hundred-millionth of a bitcoin, is named a satoshi.

Mavis Batey's March 1941 break into Italian naval Enigma set up which Royal Navy victory off Greece?

Cape Matapan saw Admiral Andrew Cunningham's British and Australian ships intercept and sink or cripple several Italian warships from 27 to 29 March 1941.

Which Bletchley mathematician deduced the Lorenz machine's full structure without ever seeing one?

Bill Tutte's diagnosis of the twelve-wheel machine was later called one of the greatest intellectual feats of the war; Bletchley saw a real one only in 1945.

The faster Colossus Mark 2 first ran on 1 June 1944, just in time for which Allied operation?

The Normandy landings came five days later, and the Mark 2's shift registers let it run five times faster than the original; ten Colossi were working by the war's end.

Bombe outstations such as Eastcote and Stanmore were staffed mostly by which uniformed organisation?

Women's Royal Naval Service members, the Wrens, ran the machines in shifts; at one point about 70 bombes were expected to be run by some 700 of them.

Which university's Beinecke Library has held the undeciphered Voynich manuscript since 1969?

Yale catalogues it as MS 408; its vellum has been carbon-dated to 1404–1438, and it is named for Wilfrid Voynich, the Polish book dealer who bought it in 1912.

Which artist made Kryptos, the 1990 CIA courtyard sculpture whose fourth passage defied codebreakers for decades?

Jim Sanborn dedicated the piece at Langley on 3 November 1990, and he has hinted that a fifth message will appear once all four are read.

The Navajo code used by the Marines in the Pacific stayed classified until which year?

1968 was the year the operation was declassified, the first recognition the code talkers received; the last of the original 29, Chester Nez, died in 2014.

Suetonius says Augustus shifted letters by one without wrapping round, writing what in place of Z?

AA replaced Z in the emperor's system, Suetonius writes, because his one-step shift simply ran off the end of the Latin alphabet instead of looping back.

In 2010 Kryptos's sculptor revealed that six letters of its fourth passage decode to which city?

Berlin is what the letters NYPVTT at positions 64 to 69 become, and the artist added that solvers had 'better delve into that particular clock'.

The 1843 treasure-hunt story 'The Gold-Bug' is set on which patch of South Carolina coast near Charleston?

Sullivan's Island is where William Legrand lives in a hut with his servant Jupiter, and the story is often read as an early piece of detective fiction.