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Cryptographer

Cryptographer

Pre-19th century

- Leone Battista Alberti, polymath/universal genius, inventor of polyalphabetic substitution (see frequency analysis for the significance of this -- missed by most for a long time and 'dumbed down' in the Vigenère cipher), and what may have been the first mechanical encryption aid.
- Giovanni Battista della Porta, author of a seminal work on cryptanalysis.
- Julius Caesar, Roman general/politician/author/assassination victim, has the Caesar cipher is named after him, and a lost work on cryptography by Probus (probably Valerius Probus) is claimed to have covered his use of military cryptography in some detail. It is likely, however, that he did not invent the cypher named after him, as other substitution ciphers were in use well before his time.
- Johannes Trithemius, mystic and first to describe tableaux (tables) for use in polyalphabetic substitution. Wrote an early work on steganography and cryptography generally.
- Philips van Marnix, lord of Sint-Aldegonde, decyphered Spanish messages for William the Silent during the Dutch revolte against the Spanish.

Pre-computer

- Charles Babbage, UK, 19th century mathematician who, about the time of the Crimean War, secretly developed an effective attack against polyalphabetic substitution ciphers. His development was published independently a few years later by Friedrich Kasiski, a Prussian officer. Babbage also designed, and had partially built, the first programmable digital computer, the Analytical Engine. He first designed and had partially built the Difference engine for reduced errors in the preparation of mathematical tables -- specifically including navigational tables, thus accounting for the interest of the British Government in the project.
- Alistair Denniston, UK, director of GC&CS at Bletchley Park during WWII.
- Nigel de Grey, UK, member of the Room 40 British codebreaking team who played an important role in the decryption of the Zimmermann Telegram during WWI
- Elizebeth Friedman, US, wife of William F, and cryptographer in her own right for the Coast Guard, Treasury Department, and assorted other US Government agencies in the 1920s and 1930s. Co-author of the most respected book on cyphers in Shakespeare. The spelling of her name is correct with three 'e's.
- William F. Friedman, US, introduced statistical methods into cryptography; some would describe him as the founder of modern cryptography. Cryptography and genetics director at the Riverbank Laboratories before WWI, wrote extensively on cryptographic theory and practice, and became the US Army's chief (and for some time only) cryptographer, patented several cryptography related inventions some of which are still secret 60+ years later, including some aspects of the SIGABA machine. Co-author of the most respected book on cyphers in Shakespeare.
- Friedrich Kasiski, author of the first published attack on the Vigenère cipher, now known as the Kasiski test (although Charles Babbage discovered a similar attack a few years earlier -- his work was not published).
- Auguste Kerckhoffs, whose design principles have become axioms.
- Dilwyn Knox, UK, Classics scholar and eccentric; WWI Room 40 member who stayed with cryptography between the Wars, becoming the chief cryptanalyst of the GC&CS before WWII. Broke commercial Enigma. Famous for solving problems in the bath.
- Solomon Kullback, US, one of William Friedman's first three employees at the SIS in the 30's.
- Leo Marks, UK, World War II cryptographer and SOE cryptography director, playwright, author of Between Silk and Cyanide.
- Marian Rejewski: Polish mathematician-cryptologist who first broke German Enigma ciphers in December 1932, laying the foundations for Polish Enigma decryption with his colleagues Jerzy Różycki and Henryk Zygalski, and subsequently for British Enigma decryption ("Ultra") during World War II at Bletchley Park. Reconstructed the Enigma machine; invented the cyclometer and the card catalog produced by it, and the cryptologic bomb.
- John Joseph Rochefort, US, mustang Navy officer (ie, ex enlisted) who early specialized in cryptography and languages, following Safford. A Japanese speaker. Became director of Station Hypo in Hawaii which made major contributions to the break into JN-25 after the attack on Pearl Harbor which led to the successful ambush at Midway. Casualty of power struggle within USN cryptography organization, was forced out of cryptography, and finished WWII in command of a dry dock in California. Honored posthumously for his Hawaiian cryptography work.
- Frank Rowlett, US, leader of the team that broke Purple, contributor to the design of SIGABA. One of William Friedman's first three employees at the SIS.
- Jerzy Różycki: Polish mathematician-cryptologist, Marian Rejewski's colleague in decrypting German Enigma ciphers. Devised the "clock" method for determining which rotor was in the far-right position.
- Claude Elwood Shannon, US, founded the modern theory of cryptography (ca. WW II), proved the one-time pad to be unbreakable, founded and invented/developed information theory and major aspects of communication theory, one of the principal developers of the theory of error-correcting codes (with Richard Hamming), made major advances in logic circuit design in his Master's thesis.
- Laurance Safford, US, chief cryptographer for the US Navy for 2 decades+. Also its first. Pioneered what became OP-20-G in WWII. One of the first Japanese speaking officers in the US Navy.
- Abraham Sinkov, US, one of William Freidman's first three employees at the SIS in the 1930s.
- John Tiltman, UK, British Army officer from Scotland, talented cryptographer/cryptanalyst. Contributed significantly before WWII in the era of hand cryptanalysis and during/after WW II in the era of machine assisted cryptanalysis. Worked at Bletchley Park and GCHQ.
- Alan Mathison Turing, UK, one of the most original minds of the 20th century and one the chief cryptographers at Bletchley Park during World War II. Made major contributions to the theory of computation, and can even be regarded as its originator. Made major contributions to the engineering design and development of early computer hardware and software at the NPL and later at the University of Manchester.
- Gordon Welchman, UK; during World War II, head of Bletchley Park's Hut Six (German Army and Air Force cipher decryption). Made major contributions to Enigma decryption.
- Sir Charles Wheatstone, inventor or the so-called Playfair cipher and general polymath.
- Herbert Yardley, US, best known for his book "The American Black Chamber". Gambler, raconteur, roving cryptographer for hire (eg, Canada, Japan) after MI8 was closed.
- Henryk Zygalski: Polish mathematician-cryptologist, Marian Rejewski's colleague in decrypting German Enigma ciphers. Invented the perforated-sheets ("Zygalski sheets") technique.

Modern

- Carlisle Adams, Can, co-developer of the CAST series of encryption algorithms, one of which was an AES contest participant. Initials accidentally correspond to first 2 letters of CAST. See also Stafford Tavares.
- Leonard Adleman, US, the 'A' in RSA, now at the University of Southern California. Has done pioneering work in DNA computing.
- Ross Anderson, UK, Cambridge University Professor, Department Director, author of many books and articles who has done important work on several aspects of cryptography and information security, including analysis of trusted computing devices, security of bank systems, robustness of protocols, steganography, "Soft TEMPEST"; cryptanalysed a number of algorithms; designed several including co-designing Serpent (an AES finalist) and Tiger a message digest algorithm. See [http://www.cl.cam.ac.uk/users/rja14 http://www.cl.cam.ac.uk/users/rja14]
- Adam Back, UK, hashcash, implemented Eternity server, RSA in 3 lines of perl on t-shirt for exportation.
- Paulo S. L. M. Barreto, Brazil, co-author with Vincent Rijmen of the Whirlpool hash function; efficient algorithms for pairing-based cryptosystems.
- Don Beaver, US, secure multiparty protocols, one-time tables, locally-random reductions, commodity crypto, adaptive security, simulatable encryption, deniability, provable security and universal composability, quantum cryptography. See [http://home.comcast.net/~beaverwww/]
- Mihir Bellare, US, Random oracles, provable security
- Daniel J. Bernstein, US, got US regulations on control of software cryptography code changed in Bernstein v. United States and also proposed interesting ideas for the factorization of large composite numbers, the goal being to break bigger RSA keys. See [http://cr.yp.to/djb.html http://cr.yp.to/djb.html]
- George Blakley, US, independent inventor of secret sharing
- Matt Blaze, US, demonstrated a security problem with the NSA Clipper chip design, published a description of a (long known 'to the trade') security problem with master keying of physical locks, and designed and implemented the Cryptographic File System for the Unix Operating System. See [http://www.crypto.com http://www.crypto.com]
- Stefan Brands, Netherlands and CAN ?, Associate Professor in Computer Science, McGill University. Author of work on digital credentials.
- Dan Boneh, Israel and US ?, Associate Professor, Applied Cryptography Group, Computer Science and Electrical Engineering, Stanford University. With G. Durfee, coauthor of the Cryptanalysis of RSA with private key d less than N^0.292. See [http://crypto.stanford.edu/~dabo/ http://crypto.stanford.edu/~dabo/]
- Gilles Brassard, CAN, Professor Computer Science, Université de Montréal. Co-invented quantum cryptography amongst much other work. See [http://www.iro.umontreal.ca/~brassard http://www.iro.umontreal.ca/~brassard]
- David Chaum, US. Author of work on anonymity systems, blind signatures.
- Don Coppersmith, US, one of the IBM team which designed the entry in the NBS competition which resulted in (after NSA / NBS modification) the Data Encryption Standard
- Claude Crépeau, CAN, Professor in Computer Science at McGill University. Zero-knowledge proofs, multi-party computations, oblivious transfer, quantum information theory. See [http://crypto.cs.mcgill.ca/~crepeau http://crypto.cs.mcgill.ca/~crepeau]
- Joan Daemen, Belgian, co-developer of Rijndael which became the AES encryption algorithm. Prolific developer of cryptographic algorithms.
- George Davida, US, Professor of Computer Science at University of Wisconsin-Milwaukee and Director of the [http://cccns.uwm.edu/ Center for Cryptography, Computer and Network Security (CCCNS)]
- Whitfield Diffie, US, one of the public inventors of asymmetric key cryptography and author
- James Ellis, UK, staff member of GCHQ who proved the possibility of 'non-secret' encryption. That proof led Clifford Cocks to invent (first) what has become known as the RSA encryption algorithm, and Malcolm Williamson (note: not the composer) to invent (first) what has become known as the Diffie-Hellman protocol.
- Taher Elgamal, US (born Egyptian), inventor of the Elgamal discrete log cryptosystem, and chief designer of the SSL protocol while at Netscape Communications Corporation
- Horst Feistel, US. Involved in early work on block ciphers at IBM, including Lucifer, DES, SP-networks and Feistel networks.
- Ian Goldberg, US, broke many cryptosystems with David Wagner.
- Lars Knudsen, Denmark, designed and analysed a large number of symmetric algorithms.
- Neal Koblitz, creator of hyperelliptic curve cryptography and independent co-creator of elliptic curve cryptography.
- Paul Kocher, US, discovered differential power analysis and designed SSLv3 See http://www.cryptography.com
- Mitsuru Matsui, Japan, discovered linear cryptanalysis, and helped design the MISTY-1, MISTY-2 and Camellia algorithms.
- Victor Miller, independent co-creator of elliptic curve cryptography.
- Bart Preneel, co-author of RIPEMD-160. See http://www.esat.kuleuven.ac.be/~preneel
- Charles Rackoff, US and CAN, Professor in Computer Science at University of Toronto. Co-author of The Knowledge Complexity of Interactive Proof Systems with Shafi Goldwasser and Silvio Micali. See http://www.cs.toronto.edu/DCS/People/Faculty/rackoff.html
- Vincent Rijmen, Belgian, co-developer of Rijndael which became the AES algorithm. See http://www.esat.kuleuven.ac.be/~rijmen
- Ronald L. Rivest, US, the 'R' in RSA, Professor at MIT and prolific crypto algorithm inventor. See http://theory.lcs.mit.edu/~rivest/
- Philip Rogaway, US, Random oracles, provable security.
- Adi Shamir, Israel, the 'S' in RSA now at Weizmann Institute, Israel. A prolific inventor of crypto algorithms, protocols, and cryptanalytic techniques.
- Bruce Schneier, US, CTO and founder of Counterpane Internet Security, Inc., one of the developers of Twofish, an AES contest finalist, several other encryption algorithms, a random number generator or two, etc. Author of Crypto-Gram a monthly newsletter on cryptography topics and several influential books. See http://www.counterpane.com (Counterpane Internet Security, Inc.) or http://www.schneier.com/ (personal website),
- Stafford Tavares, Can, co-developer of the CAST series of encryption algorithms, one of which was an AES contest participant. Initials accidentally correspond to last 2 letters of CAST. See also Carlisle Adams.
- David Wagner, US, discovered attacks on many widely deployed algorithms and was one of the developers of Twofish, an AES contest finalist
- Xiaoyun Wang, China, one of the authors of the most successful breaks on commonly used hash like MD5 and SHA-1. See [http://www.infosec.sdu.edu.cn/people/wangxiaoyun.htm http://www.infosec.sdu.edu.cn/people/wangxiaoyun.htm]
- Scott Vanstone, Canada, one of the founders of Certicom, inventors of MQV, and promoter of ECC.

External link

- [http://www.swcp.com/~mccurley/cryptographers/cryptographers.html List of cryptographers' home pages]
- cryptographers ko:암호학자 ja:暗号研究者の一覧

Leone Battista Alberti

]]Leone Battista Alberti (February 14 1404 – 25th April 1472), Italian painter, poet, linguist, philosopher, cryptographer, musician, architect, and general Renaissance polymath . His life was described in Giorgio Vasari's Vite. In Italy, his first name is usually spelled Leon. Alberti was born in Genoa as an illegitimate son of a family of Florentine merchants. He was educated in law at the University of Bologna. Alberti embarked on a tour of Europe in his mid-twenties. His career in law was curtailed by an illness which induced a partial loss of memory; Alberti then turned his abilities to science and art. He died in Rome.

Contributions

Alberti made a variety of contributions to several fields:
- In art, He is best known for his treatise De pictura (On painting) (1435) which contained the first scientific study of perspective. An Italian translation of De pictura (Della pittura) was published the year following the Latin version and was dedicated to Filippo Brunelleschi. He also wrote works on sculpture, De Statua.
- He was so skilled in Latin verse that a comedy he wrote in his twentieth year, entitled Philodoxius, would later deceive the younger Aldus Manutius, who edited and published it as the genuine work of Lepidus.
- He has been credited with being the actual author of the Hypnerotomachia Poliphili, a strange fantasy novel, whose typographic qualities and illustrations have made it legendary as one of the most beautiful books ever printed. There is a good deal of debate about this attribution, however.
- In music, he was reputed one of the first organists of the age. He held the appointment of canon in the metropolitan church of Florence, and thus had leisure to devote himself to his favourite art.
- In architecture he is generally regarded as one of the most devoted to restoring the formal language of classical architecture. At Rome he was employed by Pope Nicholas V in the restoration of the papal palace and of the restoration of the Roman aqueduct of Acqua Vergine, which debouched into a simple basin designed by Alberti, which was swept away later by the Baroque Trevi Fountain. At Mantua he designed the church of Sant'Andrea, and at Rimini the celebrated church of San Francesco. On a commission from the Rucellai family he designed the principal facade of the church of Santa Maria Novella in Florence, as well as the family palace in the Via della Scala, now known as the Palazzo Strozzi. He wrote an influential work on architecture, De Re Aedificatoria, which had been translated into Italian, French, Spanish and English by the 18th century. The most accurate English translation was by Giacomo Leoni in the early 18th century. In it he proposed new methods of fortification which became the standard defense for towns in the age of gunpowder, and dominated siege planning for hundreds of years.
- Apart from his treatises on the arts, Alberti also wrote: Philodoxus (Lover of Glory, 1424), De commodis litterarum atque incommodis (On the Advantages and Disadvantages of Literary Studies, 1429), Intercoenales (Table Talk, ca. 1429), Della famiglia (On the Family, begun 1432) Vita S. Potiti (Life of St. Potitus, 1433), De iure (On Law, 1437), Theogenius (The Origin of the Gods, ca. 1440), Profugorium ab aerumna (Refuge from Mental Anguish, 1442-43), Momus (1450) and De Iciarchia (On the Prince, 1468).
- Alberti was an accomplished cryptographer by the standard of his day, and invented both polyalphabetic ciphers and machine-assisted encryption using his cipher disk. The polyalphabetic cipher was, at least in principle, for it was not properly used for several hundred years, the most significant advance in cryptography since before Julius Caesar's time. Cryptography historian David Kahn titles him the "Father of Western Cryptography", pointing to three significant advances in the field which can be attributed to Alberti: "the earliest Western exposition of cryptanalysis, the invention of polyalphabetic substitution, and the invention of enciphered code" (The Codebreakers, 1967).
- According to Alberti himself, in a short autobiography, he was capable of "standing with his feet together, and springing over a man's head." Alberti also claimed that he "excelled in all bodily exercises; could, with feet tied, leap over a standing man; could in the great cathedral, throw a coin far up to ring against the vault; amused himself by taming wild horses and climbing mountains." Needless to say, many in the Renaissance promoted themselves in various ways and Alberti's eagerness to promote his skills should be understood, to some extent, within that framework.
- He was also interested in the drawing of maps and worked with the astronomer and cartographer Paolo Toscanelli.

Trivia

He is the Renaissance man referenced in the title of the film Renaissance Man.

External links

- Momus, Latin text and English translation, 2003 ISBN 0-674-00754-9
- Online resources for Alberti's buildings
- [http://www.greatbuildings.com/buildings/S._Andrea.html S. Andrea, Mantua, Italy]
- [http://www.greatbuildings.com/buildings/S._Andrea.html Sta. Maria Novella, Florence, Italy] Alberti Alberti Alberti Alberti Alberti Alberti Alberti Alberti Alberti Alberti Alberti Alberti Alberti ko:레온 바티스타 알베르티 ja:レオン・バッティスタ・アルベルティ

Polymath

:Renaissance man links here. For the 1994 movie, see Renaissance Man. Renaissance Man] A polymath (also known as a polyhistor) is a person who excels in multiple fields, particularly in both arts and sciences. The most common other term for this phenomenon is Renaissance man, but also in use are Homo universalis and Uomo Universale, which in Latin and Italian, respectively, translate as "Universal Man" or "Universal Person". Note that in Latin homo may be male or female; the Latin word for a male human being is vir. Many notable polymaths lived during the European Renaissance period, and a rounded approach to education was typical of the ideals of the humanists of the time. A gentleman or courtier of that era was expected to speak several languages, play a musical instrument, write poetry and so on, thus fulfilling the Renaissance ideal. During the Renaissance, Baldassare Castiglione, in his The Book of the Courtier, wrote a guide to being a polymath. On the other hand "polymath" may be applied more strictly, taking Leonardo da Vinci or Goethe as prime examples, and requiring a universality of approach. A polymath may not necessarily be classed as a genius, which is a related classification; and certainly a genius may not display the breadth to qualify as a polymath. Albert Einstein is a prime example of a person generally regarded as a "genius" who was not a polymath.

Etymological differentiation between Polymath and Polyhistor

Many dictionaries and dictionaries of word origins list these words as synonyms. Thus today, regardless of any differentiation they may have had when originally coined, they are often taken to mean the same thing (except when used by specialists). The root terms "histor" and "math" have similar meanings in their etymological antecedents (to learn, learned, knowledge), though with some initial and ancillarily added differing qualities. Innate in "historíā" (Greek and Latin) is that the learning takes place via inquiry and narrative. "Hístōr" also implies erudition and wisdom in the polyhistor. From indo-european it shares a root with "wit." Inquiry and narrative are specific sets of pedagogical and research heuristics. Two conceivable definitions of polymath are the overt 'greatly learned,' which would be inclusive of polyhistor (though not all polymaths would be polyhistors, all polyhistors would be polymaths). Another would be that polymath via the adjunct of science from the Greek "mathēmatikè téchnē" implies that the knowledge and learning be specifically about sciences or have been gained through scientific inquiry or more broadly be mathematically-logically based. Science is a somewhat different set of specific research heuristics. References: "History", "Mathematics", "Polymath" and "Polyhistor" in one or more of: Chamber's Dictionary of Etymology, The Oxford Dictionary of Word Histories, The Cassell Dictionary of Word Histories

Polyalphabetic substitution

A polyalphabetic cipher is any cipher based on substitution, using multiple substitution alphabets. The Vigenère cipher is probably the best-known example of a polyalphabetic cipher, though it is a simplified special case. The first published polyalphabetic cipher was invented by Leon Battista Alberti around 1467. Alberti used a Caesar cipher to encrypt a message, but whenever he wanted to he would switch to a different alphabet, indicating that he had done so by capitalizing the first letter encrypted with the new alphabet. Alberti also invented a decoder device, his encryption disk, which implemented a cipher equivalent to the one published later by Johannes Trithemius. Johannes Trithemius, in a book published after his death, invented a progressive key polyalphabetic cipher. Unlike Alberti's cipher, which switched alphabets at random intervals, Trithemius switched alphabets for each letter of the message. He started with a tabula recta, a square with 26 alphabets in it (Trithemius, writing in Latin, used 24 alphabets). Each alphabet was shifted one letter to the left from the one above it, and started again with A after reaching Z, like this: Latin Trithemius's idea was to encipher the first letter of the message using the first shifted alphabet, so A became B, B became C, etc. The second letter of the message was enciphered using the second shifted alphabet, etc. Alberti's cipher disk implemented the same scheme. It had two alphabets, one on a fixed outer ring, and the other on the rotating disk. A letter is enciphered by looking for that letter on the outer ring, and encoding it as the letter underneath it on the disk. The disk started with A underneath B, and the user rotated the disk by one letter after encrypting each letter. Trithemius' cypher was trivial to break, and Alberti's machine implementation not much more difficult. Key progression in both cases was poorly concealed from attackers. Even Alberti's implementation of his polyalphabetic cypher was rather easy to break (the capitalized letter is a major clue to the cryptanalyst). For most of the next several hundred years, the significance of using multiple substitution alphabets was missed by almost everyone. Polyalphabetic substitution cypher designers seem to have concentrated on obscuring the choice of a few such alphabets (repeating as needed), not on the increased security possible by using many and never repeating any. The principle (particularly Alberti's unlimited additional substitution alphabets) was a major advance -- the most significant in the several hundred years since frequency analysis had been developed. A reasonable implementation would have been (and, when finally achieved, was) vastly harder to break. It was not until the mid-1800s (in Babbage's secret work during the Crimean War) and Friedrich Kasiski's generally equivalent public disclosure some years later, that cryptanalysis of well-implemented polyalphabetic cyphers got anywhere at all. See also: Topics in cryptography. Category:Classical ciphers

Frequency analysis

In mathematics, physics and signal processing, frequency analysis is a method to decompose a function, wave, or signal into its frequency components so that it is possible to have the frequency spectrum. ---- frequency spectrum In cryptanalysis, frequency analysis is the study of the frequency of letters or groups of letters in a ciphertext. The method is used as an aid to breaking classical ciphers. Frequency analysis is based on the fact that, in any given stretch of written language, certain letters and combinations of letters occur with varying frequencies. Moreover, there is a characteristic distribution of letters that is roughly the same for almost all samples of that language. For instance, given a section of English language, E tends to be very common, while X is very rare. Likewise, ST, NG, TH, and QU are common pairs of letters (termed bigrams or digraphs), while NZ and QJ are rare. The mnemonic phrase "ETAOIN SHRDLU" encodes the 12 most frequent letters in typical English language text. In some ciphers, such properties of the natural language plaintext are preserved in the ciphertext, and these patterns have the potential to be exploited in a ciphertext-only attack.

Frequency analysis for simple substitution ciphers

In a simple substitution cipher, each letter of the plaintext is replaced with another, and any particular letter in the plaintext will always be transformed into the same letter in the ciphertext. For instance, all e's will turn into X's. A ciphertext message containing lots of X's would suggest to a cryptanalyst that X represented e. The basic use of frequency analysis is to first count the frequency of ciphertext letters and then associate guessed plaintext letters with them. More X's in the ciphertext than anything else suggests that X corresponds to e in the plaintext, but this is not certain; t and a are also very common in English, so X might be either of them also. It is unlikely to be a plaintext z or q which are less common. Thus the cryptanalyst may need to try several combinations of mappings between ciphertext and plaintext letters. More complex use of statistics can be conceived, such as considering counts of pairs of letters, or triplets (trigrams), and so on. This is done to provide more information to the cryptanalyst, for instance, Q and U nearly always occur together in that order in English, even though Q itself is rare.

An example

Suppose Eve has intercepted the cryptogram below, and it is known to be encrypted using a simple substitution cipher: LIVITCSWPIYVEWHEVSRIQMXLEYVEOIEWHRXEXIPFEMVEWHKVSTYLXZIXLIKIIXPIJVSZEYPERRGERIM WQLMGLMXQERIWGPSRIHMXQEREKIETXMJTPRGEVEKEITREWHEXXLEXXMZITWAWSQWXSWEXTVEPMRXRSJ GSTVRIEYVIEXCVMUIMWERGMIWXMJMGCSMWXSJOMIQXLIVIQIVIXQSVSTWHKPEGARCSXRWIEVSWIIBXV IZMXFSJXLIKEGAEWHEPSWYSWIWIEVXLISXLIVXLIRGEPIRQIVIIBGIIHMWYPFLEVHEWHYPSRRFQMXLE PPXLIECCIEVEWGISJKTVWMRLIHYSPHXLIQIMYLXSJXLIMWRIGXQEROIVFVIZEVAEKPIEWHXEAMWYEPP XLMWYRMWXSGSWRMHIVEXMSWMGSTPHLEVHPFKPEZINTCMXIVJSVLMRSCMWMSWVIRCIGXMWYMX For this example, uppercase letters are used to denote ciphertext, lowercase letters are used to denote plaintext (or guesses at such), and X~t is used to express a guess that ciphertext letter X represents the plaintext letter t. Eve could use frequency analysis to help solve the message along the following lines: counts of the letters in the cryptogram show that I is the most common single letter, XL most common bigram, and XLI is the most common trigram. e is the most common letter in the English language, th is the most common bigram, and the the most common trigram. This strongly suggests that X~t, L~h and I~e. The second most common letter in the cryptogram is E; since the first and second most frequent letters in the English language, e and t are accounted for, Eve guesses that E~a, the third most frequent letter. Tentatively making these assumptions, the following partial decrypted message is obtained. heVeTCSWPeYVaWHaVSReQMthaYVaOeaWHRtatePFaMVaWHKVSTYhtZetheKeetPeJVSZaYPaRRGaReM WQhMGhMtQaReWGPSReHMtQaRaKeaTtMJTPRGaVaKaeTRaWHatthattMZeTWAWSQWtSWatTVaPMRtRSJ GSTVReaYVeatCVMUeMWaRGMeWtMJMGCSMWtSJOMeQtheVeQeVetQSVSTWHKPaGARCStRWeaVSWeeBtV eZMtFSJtheKaGAaWHaPSWYSWeWeaVtheStheVtheRGaPeRQeVeeBGeeHMWYPFhaVHaWHYPSRRFQMtha PPtheaCCeaVaWGeSJKTVWMRheHYSPHtheQeMYhtSJtheMWReGtQaROeVFVeZaVAaKPeaWHtaAMWYaPP thMWYRMWtSGSWRMHeVatMSWMGSTPHhaVHPFKPaZeNTCMteVJSVhMRSCMWMSWVeRCeGtMWYMt Using these initial guesses, Eve can spot patterns that confirm her choices, such as "that". Moreover, other patterns suggest further guesses. "Rtate" might be "state", which would mean R~s. Similarly "atthattMZe" could be guessed as "atthattime", yielding M~i and Z~m. Furthemore, "heVe" might be "here", giving V~r. Filling in these guesses, Eve gets: hereTCSWPeYraWHarSseQithaYraOeaWHstatePFairaWHKrSTYhtmetheKeetPeJrSmaYPassGasei WQhiGhitQaseWGPSseHitQasaKeaTtiJTPsGaraKaeTsaWHatthattimeTWAWSQWtSWatTraPistsSJ GSTrseaYreatCriUeiWasGieWtiJiGCSiWtSJOieQthereQeretQSrSTWHKPaGAsCStsWearSWeeBtr emitFSJtheKaGAaWHaPSWYSWeWeartheStherthesGaPesQereeBGeeHiWYPFharHaWHYPSssFQitha PPtheaCCearaWGeSJKTrWisheHYSPHtheQeiYhtSJtheiWseGtQasOerFremarAaKPeaWHtaAiWYaPP thiWYsiWtSGSWsiHeratiSWiGSTPHharHPFKPameNTCiterJSrhisSCiWiSWresCeGtiWYit In turn, these guesses suggest still others (for example, "remarA" could be "remark", implying A~k) and so on, and it is relatively straightforward to deduce the rest of the letters, eventually yielding the plaintext. In this example, Eve's guesses were all correct. This would not always be the case, however; the variation in statistics for individual plaintexts can mean that initial guesses are incorrect. It may be necessary to backtrack incorrect guesses or to analyse the available statistics in much more depth than the somewhat simplified justifications given in the above example. It is also possible that the plaintext does not exhibit the expected distribution of letter frequencies. Shorter messages are likely to show more variation. It is also possible to construct artificially skewed texts. For example, entire novels have been written that omit the letter "e" altogether — a form of literature known as a lipogram.

History and usage

lipogram The first known recorded explanation of frequency analysis (indeed, of any kind of cryptanalysis) was given by 9th century Arab polymath Abu Yusuf Yaqub ibn Ishaq al-Sabbah Al-Kindi in A Manuscript on Deciphering Cryptographic Messages (Ibraham, 1992). 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:
- Use of homophones — several alternatives to the most common letters in otherwise monoalphabetic substitution ciphers (for example, for English, both X and Y ciphertext might mean plaintext E).
- Polyalphabetic substitution, that is, the use of several alphabets — chosen in assorted, more or less devious, ways (Leone Alberti seems to have been the first to propose this); and
- Polygraphic substitution, schemes where pairs or triplets of plaintext letters are treated as units for substitution, rather than single letters (for example, the Playfair cipher invented by Charles Wheatstone in the mid 1800s). A disadvantage of all these attempts to defeat frequency counting attacks is that it increases complication of both enciphering and deciphering, leading to mistakes. Famously, a British Foreign Secretary is said to have rejected the Playfair cipher because, even if school boys could cope successfully as Wheatstone and Playfair had shown, 'our attaches could never learn it!'. The rotor machines of the first half of the 20th century (for example, the Enigma machine) were essentially immune to straightforward frequency analysis. However, other kinds of analysis ("attacks") successfully decoded messages from some of those machines. Frequency analysis requires only a basic understanding of the statistics of the plaintext language and some problem solving skills, and, if performed by hand, some tolerance for extensive letter bookkeeping. During World War II (WWII), both the British and the Americans recruited codebreakers by placing crossword puzzles in major newspapers and running contests for who could solve them the fastest. Several of the ciphers used by the Axis powers were breakable using frequency analysis (for example, some of the consular ciphers used by the Japanese). Mechanical methods of letter counting and statistical analysis (generally IBM card type machinery) were first used in WWII, possibly by the US Army's SIS. There are lurid tales of midnight expeditions by the cryptographers to machines in another Department. Today, the hard work of letter counting and analysis has been replaced by computer software, which can carry out such analyses in seconds. With modern computing power, classical ciphers are unlikely to provide any real protection for confidential data.

Frequency analysis in fiction

software Frequency analysis has been described in fiction. Edgar Allan Poe's The Gold Bug, and Arthur Conan Doyle's Sherlock Holmes tale The Adventure of the Dancing Men are examples of stories which describe the use of frequency analysis to attack simple substitution ciphers. The cipher in the Poe story is encrusted with several deception measures, but this is more a literary device than anything significant cryptographically.

References

- Helen Fouché Gaines, "Cryptanalysis", 1939, Dover. ISBN 0486200973
- Ibraham A. “Al-Kindi: The origins of cryptology: The Arab contributions”, Cryptologia, 16(2) (April 1992) pp. 97–126.
- Abraham Sinkov, "Elementary Cryptanalysis : A Mathematical Approach", The Mathematical Association of America, 1966. ISBN 0883856220.

External links

- [http://textalyser.net A word frequency analysis tool]
- [http://www.data-compression.com/english.html Statistical Distributions of English Text]
- [http://scottbryce.com/cryptograms/stats.htm Some more statistical information]
- [http://patternmedia.com/projects/character_frequency_analyzer/ Online character frequency analyzer] Category:Cryptographic attacks

Giovanni Battista della Porta

Giambattista della Porta (1538-1615). Scholar and polymath who lived in Naples, Italy. A child prodigy, Della Porta was educated at home where scientific discussions occurred. The wealth acquired from the ownership of several estates ensured that he could devote his life to his studies. His most famous work first published in 1558 entitled Natural Magic was expanded into 20 books in 1584 and translated from Latin into several European languages. Della Porta founded the Ostiosi (Men of Leisure) an early scientific society, a condition of membership being to demonstrate a new discovery in the natural sciences. The Academia Secretorum Naturae was suspected of dabbling in the Occult and Della Porta was summoned to Rome by Pope Paul V. The Society was closed down by the Inquisition but Della Porta defended and justified his search for truth in nature. He was cautioned and allowed to continue his studies of investigating nature's properties. In 1586 Della Porta published a work on Physiognomy which later influenced the Swiss Pastor Johann Kaspar Lavater (1741-1801). Della Porta wrote extensively upon a wide spectrum of subjects throughout his life - including an agricultural encyclopædia entitled Villa, as well as works on meteorology optics and astronomy. His work Phytognomica lists plants according to their geographical location. In a later edition of his Natural Magic, Della Porta described a Camera obscura with a convex lens; though he was not the inventor of this technical refinement, the popularity of his work helped spread knowledge of the device. In later life Della Porta collected rare specimens from the natural world and grew exotic plants. His private museum was visited by travellers and was one the earliest examples of Natural History museuems. It inspired the Jesuit Athanasius Kircher to begin a similar collection in Rome. Della Porta also wrote fourteen prose comedies and two dramatic tragedies which became source material for several 17th century dramatists. Della Porta's works are well-represented in the Library of Sir Thomas Browne by no less than six titles.

Cryptography

In 1563, he published De Furtivis Literarum Notis, a work in cryptography, which described a substitution cipher, and made advances towards the concept of polyalphabetic substitution. Charles J. Mendelsohn commented, "He was, in my opinion, the outstanding cryptographer of the Renaissance. Some unknown who worked in a hidden room behind closed doors may possibly have surpassed him in general grasp of the subject, but among those whose work can be studied he towers like a giant."

Works

Natural Magic 1558 expanded to 20 books 1589. English translation 1658 Available online at [http://members.tscnet.com/pages/omard1/jporta3.html] De furtivis Literarum Notis (1563) On secret codes and Cryptography Villa (1583-92) An agricultural encyclopaedia De humana physiognomia (1586) On Physiognomy De refractione optices (1589) On Optics Elementorum curvilineorum libri duo (1601) De aeris transmutanionbus (1609) On Meteorology De distillatione (1610) Della Porta's chemical experiments and observations. Porta, Giambattista della Porta, Giambattista della Porta, Giambattista della ja:ジャンバッティスタ・デッラ・ポルタ

Julius Caesar

Gaius Julius Caesar (Classical Latin: IMP·C·IVLIVS·CAESAR·DIVVS) (b. July 13, 100 BC; d. March 15, 44 BC) was a Roman military and political leader. He played an important part in the transformation of the Roman Republic into the Roman Empire. His conquest of Gaul extended the Roman world all the way to the Atlantic Ocean, with the first Roman invasion of Britain in 55 BC. He is widely considered to be one of the greatest military geniuses of all time, as well as a brilliant politician; and one of the ancient world's strongest leaders along with Alexander the Great. Alexander the Great Alexander the Great Caesar fought and won a civil war which left him undisputed master of the Roman world, and began extensive reforms of Roman society and government. He was proclaimed dictator for life, and heavily centralized the already faltering government of the weak Republic. Caesar's friend Marcus Brutus conspired with others to assassinate Caesar in hopes of saving the Republic. The dramatic assassination on the Ides of March sparked a new civil war between the Caesarians: Octavian, Mark Antony, Lepidus, and Republicans: Brutus, Cassius, and Cicero among others. This conflict ended with a Caesarian victory at the Battle of Philippi, and the formal establishment of the Second Triumvirate in which Octavian, Antony, and Lepidus shared control of Rome. Tensions between Octavian and Antony soon plunged Rome into further civil war, culminating in Antony's defeat at the Battle of Actium, and leaving Octavian as the undisputed leader of the Roman world. This period of civil wars transformed the Roman Republic into the Roman Empire with Caesar's great nephew and adopted son Octavian, later known as Caesar Augustus, installed as the first Emperor. Caesar's military campaigns are known in detail from his own written Commentaries (Commentarii), and many details of his life are recorded by later historians such as Suetonius, Plutarch, and Cassius Dio.

Early Life

Caesar was born in Rome into a well-known patrician family (gens Julia), which supposedly traced its ancestry to Julus, the son of the Trojan prince Aeneas, who according to myth was the son of Venus. According to legend, Caesar was born by Caesarian section and is its namesake, though this is unlikely because it was only performed on dead women, and his mother lived long after he was born, this legend is more likely a modern invention, as the origin of the Caesarian section is in the Latin word for to cut, caedo, -ere, caesus sum. Caesar was raised in a modest apartment building (insula) in the Suburra, a lower-class neighborhood of Rome. The Julii Caesares, although of impeccable aristocratic patrician stock, were not rich by the standards of the Roman nobility. Thus, no member of his family had achieved any outstanding prominence in recent times, though in his father's generation there was a renaissance of their fortunes. He was the namesake of his father (a praetor, who died in 85-84 BC) and his mother was Aurelia Cotta. His elder sister Julia Caesaris, was grandmother to Caesar Augustus. His paternal aunt, Julia, married Gaius Marius, a talented general and reformer of the Roman army. Marius became one of the richest men in Rome at the time and while he gained political influence, the Caesar family gained the wealth. Towards the end of Marius' life in 86 BC, internal politics reached a breaking point. During this period Roman politicians were generally divided into two factions: the Populares, which included Marius, and the Optimates, which included Lucius Cornelius Sulla. A string of disputes between these two factions led to civil war and eventually opened the way to Sulla's dictatorship. Caesar was tied to the Populares through family connections. Not only was he Marius' nephew, he was also married to Cornelia, the youngest daughter of Lucius Cornelius Cinna, Marius' greatest supporter and Sulla's enemy. To make matters worse, in the year 85 BC, just after Caesar turned 15, his father grew ill and soon died. Both Marius and his father had left Caesar much of their property and wealth in their wills. Thus, when Sulla emerged as the winner of this civil war and began his program of proscriptions, Caesar, not yet 20 years old, was in a bad position. Sulla ordered Caesar to divorce Cornelia in 82 BC, but Caesar refused and prudently left Rome to hide. Sulla pardoned Caesar and his family and allowed him to return to Rome. In a prophetic moment, Sulla was said to comment on the dangers of letting Caesar live. According to Suetonius, the dictator in relenting on Caesar's proscription said, "He whose life you so much desire will one day be the overthrow of the part of nobles, whose cause you have sustained with me; for in this one Caesar, you will find many a Marius." Despite Sulla's pardon, Caesar did not remain in Rome and left for military service in Asia and Cilicia. While still in Asia Minor, Caesar was involved in several military operations. In 80 BC, while still serving under Marcus Minucius Thermus, he played a pivotal role in the siege of Miletus. During the course of the battle Caesar showed such personal bravery in saving the lives of legionaries, that he was later awarded the corona civica (oak crown). The award was of the highest honor given to a non-commander, and when worn in public, even in the presence of the Roman Senate, all were forced to stand and applaud his presence. Back in Rome in 78 BC, when Sulla died, Caesar began his political career in the Forum at Rome as an advocate, known for his oratory and ruthless prosecution of former governors notorious for extortion and corruption. The great orator Cicero even commented, "Does anyone have the ability to speak better than Caesar?" Aiming at rhetorical perfection, Caesar traveled to Rhodes in 75 BC for philosophical and oratorical studies with the famous teacher Apollonius Molo. On the way, Caesar was kidnapped by Cilician pirates

Caesar's cursus honorum

pirates Caesar was elected quaestor by the Assembly of the People in 70 BC, at the age of 30, as stipulated in the Roman cursus honorum. This office brought with it membership in the senate. He drew the lots and was assigned with a quaestorship in Hispania Ulterior, a Roman province roughly situated in modern Portugal and southern Spain. As an administrative and financial officer, the trip was largely uneventful, but while in Hispania he had the now famous encounter with a statue of Alexander the Great. Perhaps because of his weakened emotional state coupled with a growing and now obvious personal ambition, he had a definitive and prophetic reaction to the site of the statue. At the temple of Hercules in Gades, it was said that he either broke down and cried or at the very least was deeply saddened in reaction to it. When asked why he would react so, he responded: "Do you think I have not just cause to weep, when I consider that Alexander at my age had conquered so many nations, and I have all this time done nothing that is memorable." Caesar was released early from his office as quaestor, and allowed to return to Rome. Despite any personal grief over the loss of his wife, whom all accounts suggest he loved dearly, Caesar was set to remarry in 67 BC for political gain. This time, however, he chose an odd alliance. The granddaughter of Sulla, and daughter of Quintus Pompey, Pompeia became his next wife. Although seeming to align himself with the Senatorial optimates, Caesar's other actions had little to do with conservative policy and he continued his course of support for a populares policy. Caesar supported the Lex Gabinia which granted Pompey the Great unlimited powers in dealing with Cilician Pirates. Later, and once again in the face of bitter Optimate resistance, Caesar supported the Lex Manilia which granted Pompey the unique and comprehensive command of the entire east against Mithridates. Obviously building a relationship with Rome’s great general would play into his hands later. The rivalry between Pompey and Caesar’s benefactor Crassus, seemed to have little effect on Caesar. Crassus continued to support Caesar’s enormous debts over the next few years. Between the support of the two laws regarding Pompey’s command, Caesar served as the curator of the Appian Way. The maintenance of this road, which stretched from Rome through Cumae to the heel of Italy’s boot, was an important and high profile position. While it was enormously expensive to him personally, it gave a great deal of prestige to the young Senator, and Crassus’ support made it an achievable task for Caesar. All the while, Caesar continued pursuing his judicial career until his election as curule aedile in 65 BC, along with Bibulus, a young rival and member of the optimate faction. This magisterial position was the next step in the Roman cursus honorum and provided a grand opportunity for the master of the public spectacle. The curule aediles were responsible for the construction and care of temples, maintenance of public buildings, traffic, and other aspects of Rome's daily life. Perhaps most importantly, the aediles staged public games on state holidays and managed the Circus Maximus. Caesar indebted himself to the point of near financial ruin during this time, but enhanced his image irreversibly with the common people. His games were spectacular affairs, and building projects during his term were ambitious. In a spectacle to honor his father, Caesar displayed 320 pairs of gladiators clad in silver armor at an enormous expense. Caesar pushed his agenda further by erecting statues of Marius for public display. The senate was outraged, but Caesar’s popularity made him nearly untouchable. They could, however, attempt to block his political path through other means. Caesar may have been nominated to take charge of quelling a disturbance in Egypt but was unable to win enough support to take the position. Caesar ended his year as aedile in both glory and bankruptcy. His debts reached several hundred gold talents (millions of Euros in today's currency) and threatened to hinder his future political career. His co-aedile Bibulus was so unspectacular in comparison that he later commented in frustration that the entire year’s aedile ship was credited to Caesar alone, instead of both. Roman satirists ever after referred to the year as "the consulship of Julius and Caesar". His success as aedile, however, enormously helped his election as Pontifex Maximus (high priest) in 63 BC, following the death of the previous pontifex Quintus Caecilius Metellus Pius. This office came with a house — the Domus Publica (public house) — in the Forum, the responsibility of all Roman religious affairs and the custody of the Vestal virgins under his roof. For Caesar, it also meant a relief of his debts. This election bestowed considerable power on Caesar, with the opportunity for income. The Pontifex was elected to a lifetime term. While technically not a political office, the pontificate provided considerable advantages in dealing with the Senate and legislation. Scandal marred Caesar's debut as Pontifex. Following Cornelia's death, Caesar had married Pompeia, a granddaughter of Sulla, in 67 BC. As the wife of the Pontifex and an important matrona, Pompeia was responsible for the organization of the Bona Dea festival in December. These sacred rites were exclusive to women. However, Publius Clodius Pulcher managed to sneak in the house disguised as a woman. This was absolute sacrilege and Pompeia received a letter of divorce. Caesar himself admitted that she might be innocent of wrongdoing, but that: "Caesar's wife, like the rest of Caesar's family, must be above suspicion." Sixty-three BC proved especially difficult, not only for Caesar, but for the Roman Republic itself. Caesar won the office of urban Praetor, but before he could take office, the Catiline Conspiracy erupted, putting Caesar in direct conflict with the optimates once again. Lucius Sergius Catilina, twice a candidate for consul, faced charges of plotting to overthrow the Republic through armed rebellion. Catiline's guilt is disputed. In the elections held in late 63 BC, Marcus Tullius Cicero defeated Catiline in the consular election. Soon afterwards, Crassus received anonymous letters informing various Senators to leave Rome in order to avoid a coming massacre of government leaders. Crassus took the letters to Cicero, who presented the conspiracy concept to the Senate. Many in the Senate disbelieved him, thinking that Cicero fabricated the affair for political gain. Cicero’s oratorical eloquence, however, convinced the Senate that plot warranted extreme steps. Senatus consultum ultimum followed granting Cicero the authority to deal with the conspirators. Catiline, among others, became the prime target. In response he decided to flee Rome, but not before being implicated in a plot to assassinate Cicero. The plot failed, and Catiline left to join the rebellion in Etruria. Five notable Romans, allies of Catiline, were sentenced to death without trial. Imprisonment before trial was unheard of and if banished the men might have joined Catiline's armies in Etruria. During the Senate's deliberation, Caesar was one of the few men to argue against a death sentence. His position was defeated, due to Cato the younger's insistence, and the men were executed on the same day. This was also the day on which Caesar's affair with Servilia Caepionis was exposed to the public eye. Caesar's opposition prompted accusations — never proved — of his involvement with the conspiracy. If Caesar was implicated in the Catiline affair, it did him no lasting damage. In the following year, Caesar began a term as urban praetor. From this elite position, he once again pushed his populares policies. He asked for an account of the cost of restoring the capital, in which he was opposed by the optimates. Unsuccessful in that attempt, he strengthened his standing with Pompey, who was soon to return to Rome from his eastern campaigns. Pompey’s return troubled the optimates, who feared a Sullan-style march to Rome and dictatorship. They needed to present the city, and the surrounding countryside, as a stable environment not in need of Pompey to ‘restore order’. Pompey’s ally, Caecilius Metellus Nepos, however, took the matter to the Senate demanding that Pompey be allowed to land in Italy and do just that. Caesar supported Nepos and Pompey, but Cato defeated the motion. Nepos fled Rome to join Pompey, and Caesar was eventually stripped of the Praetorship. When a mob in support of Caesar threatened violence his position was restored. Caesar quelled the mob before any violence ensued. Towards the end of his Praetorship, Caesar again faced the serious jeopardy of prosecution for his debts. Crassus, rescuing his ally, paid off a quarter of his 20 million denarii balance. By 61 BC, Caesar was assigned the Propraetorian governorship of further Hispania, the province in which he had served as quaestor. With this appointment to a potentially profitable position, his creditors relaxed their demands. Not taking chances, Caesar left Rome earlier than this new responsibility required. Caesar and his staff rode hard, reaching the Rhone in only 8 days, and presaging his future ability to move armies at remarkable speeds. On the way, several members of his entourage noted the barbaric, and, in their view, wretched standard of living in the local villages. Caesar, demonstrating his ambition replied, "For my part, I’d rather be the first man among these fellows than the second man in Rome." During his term as governor, Caesar strengthened his relationship with these Gallic peoples, which proved to be an important factor in his later plans. Arriving in Hispania, Caesar earned a remarkable reputation for military command. Between 61 BC and 60 BC, he won considerable victories over the Gallaecians and Lusitanians. He advanced to the Atlantic Ocean and subdued tribes in the northwest part of the country that had never before bowed to the Romans. He secured sufficient spoils of war to pay off all of his debts, provide his men a considerable share of booty, and add to the Roman treasury. During one of his victories, his men hailed him as Imperator in the field, which was a vital consideration in being eligible for a triumph back in Rome. But a terrible dilemma faced Caesar. He wanted to run for Consul for 59 BC, which required his presence in Rome, but he also wanted the honor of a triumph. The optimates could use this against him, forcing him to wait outside the city, as was the custom, until they confirmed his triumph. This delay could force Caesar to miss his chance to run for Consul. In the summer of 60 BC, Caesar entered Rome to run for the highest political office in the Roman Republic, foregoing his triumph.

The First Triumvirate and the Gallic War

In 60 BC (or 59 BC) the Centuriate Assembly elected Caesar senior Consul of the Roman Republic. His junior partner was his political enemy Marcus Calpurnius Bibulus, an Optimate and personal friend of Marcus Porcius Cato. Bibulus' first act as Consul was to retire from all political activity in order to search the skies for omens. This apparently pious decision was designed to make Caesar's life difficult during his Consulship. Thus leading to the informal name of the two consuls in the consulship "Julius and Caesar." Caesar needed allies and he found them where none of his enemies expected. The leading general of the day, Gnaeus Pompeius Magnus (Pompey the Great), was unsuccessfully fighting the Senate for farmlands for his veterans. A former Consul, Marcus Licinius Crassus, allegedly the richest man in Rome, was also having problems in obtaining his long-desired military command against the Parthian Empire. Caesar desperately needed Crassus's money and Pompey's influence, and an informal alliance soon followed: The First Triumvirate (rule by three men). To confirm the alliance, Pompey married Julia Caesaris, Caesar's only daughter. Despite their differences in age and upbringing, this political marriage proved to be a love match. Following a difficult year as Consul, Caesar was appointed to a five year term as Proconsular Governor of Transalpine Gaul (current southern France) and Illyria (the coast of Dalmatia). Not content with an idle governorship, Caesar started the Gallic Wars (58 BC–49 BC) in which he conquered all of Gaul (the rest of current France) and parts of Germania and annexed them to Rome. Among his legates were his cousins Lucius Julius Caesar and Mark Antony, Titus Labienus and Quintus Tullius Cicero, the younger brother of Caesar's political opponent, Cicero. Caesar defeated the Helvetii (in Switzerland) in 58 BC, the Belgic confederacy and the Nervii in 57 BC and the Veneti in 56 BC. On August 26th 55 BC he attempted an invasion of Britain and, in 52 BC he defeated a union of Gauls led by Vercingetorix at the battle of Alesia. He recorded his own accounts of these campaigns in De Bello Gallico ("On the Gallic War"). According to Plutarch, the whole campaign resulted in 800 conquered cities, 300 subdued tribes, one million men sold to slavery and another three million dead in battle fields. Ancient historians notoriously exaggerated numbers of this kind, but Caesar's conquest of Gaul was certainly the greatest military invasion since the campaigns of Alexander the Great. The victory was also far more lasting than those of Alexander's - Gaul never regained its Celtic identity, never attempted another nationalist rebellion, and remained loyal to Rome until the fall of the Western Empire in 476. Despite his successes and the benefits to Rome, Caesar remained unpopular among his peers, especially the conservative faction, who suspected him of wanting to be king. In 55 BC, his partners Pompey and Crassus were elected consuls and honored their agreement with Caesar by prolonging his proconsulship for another five years. This was the last act of the First Triumvirate. In 54 BC, Julia Caesaris died in childbirth, leaving both Pompey and Caesar heartbroken. Crassus was killed in 53 BC during his campaign in Parthia. Without Crassus or Julia, Pompey drifted towards the Optimates. Still in Gaul, Caesar tried to secure Pompey's support by offering him one of his nieces in marriage, but Pompey refused. Instead, Pompey married Cornelia Metella, the daughter of Metellus Scipio, one of Caesar's greatest enemies.

The civil war

Metellus Scipio In 50 BC, the Senate, led by Pompey, ordered Caesar to return to Rome and disband his army because his term as Proconsul had finished. Moreover, the Senate forbade Caesar to stand for a second consulship in absentia. Caesar thought he would be prosecuted and politically marginalized if he entered Rome without the immunity enjoyed by a Consul or without the power of his army. Pompey accused Caesar of insubordination and treason. On January 10, 49 BC Caesar crossed the Rubicon (the frontier boundary of Italy) with only one legion and ignited civil war. Historians differ as to what Caesar said upon crossing the Rubicon; the two competing lines are "Alea iacta est" ("The die is cast"), and "Let the dice fly high!" (a line from the New Comedy poet Menander). This minor controversy is occasionally seen in modern literature when an author attributes the less popular Menander line to Caesar. The Optimates, including Metellus Scipio and Cato the Younger, fled to the south, not knowing that Caesar had only his Tenth Legion with him. Caesar pursued Pompey to Brundisium, hoping to restore their alliance of ten years prior. Pompey eluded him, however, and Caesar made an astonishing 27-day route-march to Hispania where he defeated Pompey's lieutenants. He then returned east, to challenge Pompey in Greece where on July 10, 48 BC at Dyrrhachium Caesar barely avoided a catastrophic defeat. He decisively defeated Pompey, despite Pompey's numerical advantage (nearly twice the number of infantry and considerably more cavalry), at Pharsalus in an exceedingly short engagement in 48 BC. Pompey fled to Egypt, where he was murdered by an officer of King Ptolemy XIII. In Rome, Caesar was appointed dictator, with Mark Antony as his master of the horse; Caesar resigned this dictatorate after eleven days and was elected to a second term as consul with Publius Servilius Vatia Isauricus as his colleague. He pursued Pompey to Alexandria, where he camped his army and became involved with the Alexandrine civil war between Ptolemy and his sister, wife, and co-regnant queen, the Pharaoh Cleopatra VII. Perhaps as a result of Ptolemy's role in Pompey's murder, Caesar sided with Cleopatra; he is reported to have wept at the sight of Pompey's head, which was offered to him by Ptolemy's chamberlain Pothinus as a gift. In any event, Caesar defeated the Ptolemaic forces and installed Cleopatra as ruler, with whom he fathered his only known biological son, Ptolemy XV Caesar, better known as "Caesarion". Caesar and Cleopatra never married. After spending the first months of 47 BC in Egypt, Caesar went to the Middle East, where he annihilated King Pharnaces II of Pontus in the battle of Zela; his victory was so swift and complete that he commemorated it with the words Veni, vidi, vici ("I came, I saw, I conquered"). Thence, he proceeded to Africa to deal with the remnants of Pompey's senatorial supporters. He quickly gained a significant victory at Thapsus in 46 BC over the forces of Metellus Scipio (who died in the battle) and Cato the Younger (who committed suicide). Nevertheless, Pompey's sons Gnaeus Pompeius and Sextus Pompeius, together with Titus Labienus, Caesar's former propraetorian legate (legatus propraetore) and second in command in the Gallic War, escaped to Hispania. Caesar gave chase and defeated the last remnants of opposition in the Munda in March 45 BC. During this time, Caesar was elected to his third and fourth terms as consul in 46 BC (with Marcus Aemilius Lepidus) and 45 BC (without colleague).

After the war

Caesar returned to Italy in September, 45 BC. Among his first tasks he filed his will, naming Octavian as his sole heir. The Senate had already begun bestowing honors on Caesar in absentia. Even though Caesar had not proscribed his enemies, instead pardoning nearly every one of them, there seemed to be little open resistance to him. Great games and celebrations were held on April 21 to honor Caesar’s great victory. Along with the games, Caesar was honored with the right to wear triumphal clothing, including a purple robe (reminiscent of the kings of Rome) and laurel crown, on all public occasions. A large estate was being built at Rome’s expense, and on state property, for Caesar’s exclusive use. The title of Imperator became a legal title that he could use in his name for the rest of his life. An ivory statue in his likeness was to be carried at all public religious processions. Images of Caesar show his hair combed forward in an attempt to conceal his baldness, Another statue of Caesar was placed in the temple of Quirinus with the inscription To the Invincible God. Since Quirinus was the deified likeness of the city and its founder and first King, Romulus, this act identified Caesar not only on equal terms with the gods, but with the ancient kings as well. A third statue was erected on the capitol alongside those of the seven Roman Kings and with that of Lucius Junius Brutus, the man who led the revolt to expel the Kings originally. In yet more scandalous behavior, Caesar had coins minted bearing his likeness. This was the first time in Roman history that a living Roman was featured on a coin. When Caesar returned to Rome in October of 45 BC, he gave up his fourth Consulship (which he held without colleague) and placed Quintus Fabius Maximus and Gaius Trebonius as suffect consuls in his stead. This irritated the Senate because he completely disregarded the Republican system of election, and performed these actions at his own whim. He celebrated a fifth triumph, this time to honor his victory in Hispania. The Senate continued to encourage more honors. A temple to Libertas was to be built in his honor, and he was granted the title Liberator. They elected him Consul for life, and allowed to hold any office he wanted, including those generally reserved for Plebeians. Rome also seemed willing to grant Caesar the unprecedented right to be the only Roman to own imperium. In this, Caesar alone would be immune from legal prosecution and would technically have the supreme command of the legions. More honors continued, including the right to appoint half of all magistrates, which were supposed to be elected positions. He also appointed magistrates to all provincial duties, a process previously done by draw of lots or through the approval of the Senate. The month of his birth, Quintilis, was renamed July (Latin Julius) in his honor and his birthday, July 13, was recognized as a national holiday. Even a tribe of the people’s assembly was to be named for him. A temple and priesthood, the Flamen maior, was established and dedicated in honor of his family. Caesar, however, did have a reform agenda and took on various social ills. He passed a law that prohibited citizens between the ages of 20 and 40 from leaving Italy for more than 3 years unless on military assignment. This theoretically would help preserve the continued operation of local farms and businesses and prevent corruption abroad. If a member of the social elite did harm or killed a member of the lower class, then all the wealth of the perpetrator was to be confiscated. Caesar demonstrated that he still had the best interest of the state at heart, even if he believed that he was the only person capable of running it. A general cancellation of one-fourth of all debt also greatly relieved the public and helped to endear him even further to the common population. Caesar tightly regulated the purchase of state-subsidized grain, prostitutes, and forbade those who could afford privately supplied grain from purchasing from the grain dole. He made plans for the distribution of land to his veterans and for the establishment of veteran colonies throughout the Roman world. One of his most wide-ranging reforms came after his election to Pontifex Maximus for life. Caesar ordered a complete overhaul of the Roman calendar, establishing a 365-day year with a leap year every fourth year (this Julian Calendar was subsequently modified by Pope Gregory XIII in 1582 into the modern calendar). As a result of this reform, the year 46 BC was in fact 445 days long to bring the calendar into line. Additionally great public works were undertaken. Rome was a city of great urban sprawl and unimpressive brick architecture and Rome desperately needed a renewal. A new Rostra of marble, along with court houses and marketplaces were built. A public library under the great scholar Varro was also under construction. The Senate house, the Curia Hostilia, which had been recently repaired, was abandoned for a new marble project to be called the Curia Julia. The city Pomerium (sacred boundary) was extended allowing for additional growth. Pomerium Plutarch records that at one point, Caesar informed the Senate that his honours were more in need of reduction than augmentation, but withdrew this position so as not to appear ungrateful. He was given the title Pater Patriae ("Father of the Fatherland"). He was appointed dictator a third time, and then nominated for nine consecutive one-year terms as dictator, effectually making him dictator for ten years. He was also given censorial authority as prefect of morals (praefectus morum) for three years. At the onset of 44 BC, the honors heaped upon Caesar continued and the rift between him and the aristocrats deepened. He had been named Dictator Perpetuus, making him dictator for the remainder of his life . This title even began to show up on coinage bearing Caesar’s likeness, placing him above all others in Rome. Some among the population even began to refer to him as ‘Rex’ (Latin king), but Caesar refused to accept the title. At Caesar’s new temple of Venus, a senatorial delegation went to consult with him and Caesar refused to stand to honor them upon their arrival. Though the event is clouded by several different versions of the story, it’s quite clear that the Senators present were deeply insulted. He attempted to rectify the situation later by exposing his neck to his friends and saying he was ready to offer it to anyone who would deliver a stroke of the sword. This seemed to at least cool the situation, but the damage was done. The seeds of conspiracy were beginning to grow.

Assassination

The fear of Caesar becoming king continued when someone placed a diadem on the statue of Caesar on the Rostra. The tribunes, Gaius Epidius Marcellus and Lucius Caesetius Flavius, removed the diadem. Not long after the incident with the diadem, the same two tribunes had citizens arrested after they called out the title ‘Rex’ to Caesar as he passed by on the streets of Rome. Now seeing his supporters threatened, Caesar acted harshly. He ordered those arrested to be released, and instead took the tribunes before the Senate and had them stripped of their positions. Caesar had originally used the sanctity of the Tribunes as one reason for the start of the civil war, but now revoked their power for his own gain. At the coming festival of the Lupercalia, the biggest test of the Roman people for their willingness to accept Caesar as King was to take place. On February 15, 44 BC, Caesar sat upon his gilded chair on the Rostra, wearing his purple robe, red shoes and a golden laurel and armed with the title of Dictator Perpetuus. The race around the pomerium was a tradition of the festival, and Mark Antony ran into the forum and was raised to the Rostra by the priests attending the event. Antony produced a diadem and attempted to place it on Caesar’s head, saying "the people offer this (the title of king) to you through me." There was, however, little support from the crowd and Caesar quickly refused being sure that the diadem didn’t touch his head. The crowd roared with approval, but Antony, undeterred attempted to place it on Caesar’s head again. Still there was no voice of support from the crowd and Caesar rose from his chair and refused Antony again, saying, "I will not be king of Rome. Jupiter alone is King of the Romans." The crowd wildly endorsed Caesar’s actions. All the while Caesar was still planning a campaign into Dacia and then Parthia. The Parthian campaign stood to bring back considerable wealth to Rome, along with the potential return of the standards that Crassus had lost over nine years earlier. An ancient legend has told that Partia could only be conquered by a king, so Caesar was authorized by the Senate to wear a crown anywhere in the empire, save Italy. Caesar planned to leave in April of 44 BC, and the secret opposition that was steadily building had to act fast. Made up mostly of men that Caesar had pardoned already, they knew their only chance to rid Rome of Caesar was to prevent him ever leaving for Parthia. The Roman Senate traditionally met in the Curia Hostilia, which had been recently repaired from the fires that destroyed it years before, but the Senate had abandoned it for the new house under construction. Thus Caesar summoned the Senate to meet in the Theatrum Pompeium (built by Pompey) on the Ides of March (March 15) 44 BC. A few days before, a soothsayer had said to Caesar, "Beware the Ides of March." As the Senate convened, Caesar was attacked and stabbed to death by a group of senators who called themselves the Liberators (Liberatores); the Liberators justified their action on the grounds that they committed tyrannicide, not murder, and were preserving the Republic from Caesar's alleged monarchical ambitions. Among the assassins who locked themselves in the Temple of Jupiter were Gaius Trebonius, Decimus Junius Brutus, Marcus Junius Brutus, and Gaius Cassius Longinus; Caesar had personally pardoned most of his murderers or personally advanced their careers. Marcus Brutus was a distant cousin of Caesar and named as one of his testamentary heirs. There is also speculation that Marcus Brutus was an illegitimate child of Caesar's, since he had an affair with Servilia Caepionis, Brutus' mother; however, Caesar was 15 years old at the time Brutus was born. Caesar sustained 23 (as much as 35 by some accounts) stab wounds, which ranged from superficial to mortal, and ironically fell at the feet of a statue of his friend turned rival, Pompey the Great. Pompey had recently been deified by the Senate. Some accounts report that Caesar prayed to Pompey as he lay dying. His last words have been variously reported as:
- και συ τεκνον; (Kai su, teknon?) (Gr., "Even you, my child?" – from Suetonius)
- Tu quoque, Brute, fili mi! (Lat., "You too, Brutus, my son!" – a modern Latin translation of the Greek quotation from Suetonius)
- Et tu, Brute? (Lat., "And (even) you, Brutus?" – from Shakespeare's play, Julius Caesar) It has been speculated that Caesar knew of the plot against his life, and allowed it to proceed, going so far as to dismiss his guard contingent in order to allow the conspirators to kill him. This theory hinges on Caesar's epilepsy, a condition attributed to him by several sources including Plutarch. Proponents of the theory suggest that Caesar deliberately arranged to be murdered by the Senate, to spare himself the indignity of increasing seizures as he aged, and to insure his own legacy. While the public outrage over Caesar's murder did provide a favorable climate for Caesar's heir Octavian to take power, this theory is not currently backed by sufficient evidence to give it credence.

Detailed account

Here follows the most detailed account of Caesar's assassination, written by Nicolaus of Damascus a few years after the event and likely based on eyewitness reports.

The Plan

:"The conspirators never met openly, but they assembled a few at a time in each others' homes. There were many discussions and proposals, as might be expected, while they investigated how and where to execute their design. Some suggested that they should make the attempt as he was going along the Sacred Way, which was one of his favorite walks. Another idea was for it to be done at the elections during which he had to cross a bridge to appoint the magistrates in the Campus Martius; they should draw lots for some to push him from the bridge and for others to run up and kill him. A third plan was to wait for a coming gladiatorial show. The advantage of that would be that, because of the show, no suspicion would be aroused if arms were seen prepared for the attempt. But the majority opinion favored killing him while he sat in the Senate, where he would be by himself since non-Senators would not be admitted, and where the many conspirators could hide their daggers beneath their togas. This plan won the day."

Bad Omens

:"Before he entered the chamber, the priests brought up the victims for him to make what was to be his last sacrifice. The omens were clearly unfavorable. After this unsuccessful sacrifice, the priests made repeated other ones, to see if anything more propitious might appear than what had already been revealed to them. In the end they said that they could not clearly see the divine intent, for there was some transparent, malignant spirit hidden in the victims. Caesar was annoyed and abandoned divination till sunset, though the priests continued all the more with their efforts. :"Those of the murderers present were delighted at all this, though Caesar's friends asked him to put off the meeting of the Senate for that day because of what the priests had said, and he agreed to do this. But some attendants came up, calling him and saying that the Senate was full. He glanced at his friends, but Brutus approached him again and said, 'Come, good sir, pay no attention to the babblings of these men, and do not postpone what Caesar and his mighty power has seen fit to arrange. Make your own courage your favorable omen.' He convinced Caesar with these words, took him by the right hand, and led him to the Senate which was quite near. Caesar followed in silence."

The Final Attack

:"The Senate rose in respect for his position when they saw him entering. Those who were to have part in the plot stood near him. Right next to him went Tillius Cimber, whose brother had been exiled by Caesar. Under pretext of a humble request on behalf of this brother, Cimber approached and grasped the mantle of his toga, seeming to want to make a more positive move with his hands upon Caesar. Caesar wanted to get up and use his hands, but was prevented by Cimber and became exceedingly annoyed. :"That was the moment for the men to set to work. All quickly unsheathed their daggers and rushed at him. First Servilius Casca struck him with the point of the blade on the left shoulder a little above the collar-bone. He had been aiming for that, but in the excitement he missed. Caesar rose to defend himself, and in the uproar Casca shouted out in Greek to his brother. The latter heard him and drove his sword into the ribs. After a moment, Cassius made a slash at his face, and Decimus Brutus pierced him in the side. While Cassius Longinus was trying to give him another blow he missed and struck Marcus Brutus on the hand. Minucius also hit out at Caesar and hit Rubrius in the thigh. They were just like men doing battle against him. :"Under the mass of wounds, he fell at the foot of Pompey's statue. Everyone wanted to seem to have had some part in the murder, and there was not one of them who failed to strike his body as it lay there, until, wounded twenty-three times, he breathed his last. "

Aftermath

Caesar's death also marked, ironically, the end of the Roman Republic, for which the assassins had struck him down. The Roman middle and lower classes, with whom Caesar was immensely popular, and had been since Gaul and before, were enraged that a small group of high-browed aristocrats had killed their champion. Antony did not give the speech Shakespeare penned for him ("Friends, Romans, countrymen, lend me your ears!") but he did give a dramatic eulogy which appealed to the common people, a perfect example of what public thinking was following Caesar's murder. Antony, who'd been as of late drifting from Caesar, capitalized on the grief of the Roman mob and threatened to unleash them on the Optimates, perhaps with the intent of taking control of Rome himself. But Caesar named his grand nephew Gaius Octavius sole heir of his vast fortune, giving Octavius both the immensely powerful Caesar name and control of one of the largest amounts of money in the Republic. In addition, Gaius Octavius was also, for all intents and purposes, the son of the great Caesar, and consequently the loyalty of the Roman populace shifted from dead Caesar to living Octavius. Octavius, only aged 19 at the time of Caesar's death, proved to be ruthless and lethal, and while Antony dealt with Decimus Brutus in the first round of the new civil wars, Octavius consolidated his position. In order to combat Brutus and Cassius, who were massing an army in Greece, Antony needed both the cash from Caesar's war chests and the legitimacy that Caesar's name would provide any action he took against the two. A new Triumvirate was found - the Second and final one, with Octavius, Antony, and Caesar's loyal cavalry commander Lepidus as the third member. This Second Triumvirate deified Caesar as divus iulius and – seeing that Caesar's clemency had resulted in his murder – brought back the horror of proscription, abandoned since Sulla, and proscribed its enemies in large numbers in order to seize even more funds for the second civil war against Brutus and Cassius, whom Antony and Octavian defeated at Philippi. A third civil war then broke out between Octavian on one hand and Antony and Cleopatra on the other. This final civil war, culminating in Antony and Cleopatra's defeat at Actium, resulted in the ascendancy of Octavian, who became the first Roman emperor, under the name Caesar Augustus. In 42 BC, Caesar was formally deified as "the Divine Julius" (Divus Iulius), and Caesar Augustus henceforth became Divi filius ("Son of God").

Caesar's literary works

Caesar was considered during his lifetime to be one of the finest orators and authors of prose in Rome—even Cicero spoke highly of Caesar's rhetoric and style. Among his most famous works were his funeral oration for his paternal aunt Julia (Marius's widow) and his Anticato, a document written to blacken Cato's reputation and respond to Cicero's Cato memorial. Unfortunately, the majority of his works and speeches have been lost. The most famous of his surviving works are:
- The Commentarii de Bello Gallico (Commentaries on the