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迈尔(Julius Robert Mayer,)
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你可能喜欢From Wikipedia, the free encyclopedia
The action of a Caesar cipher is to replace each plaintext letter with a different one a fixed number of places down the alphabet. The cipher illustrated here uses a left shift of three, so that (for example) each occurrence of E in the plaintext becomes B in the ciphertext.
In , a Caesar cipher, also known as Caesar's cipher, the shift cipher, Caesar's code or Caesar shift, is one of the simplest and most widely known
techniques. It is a type of
in which each letter in the
is replaced by a letter some fixed number of positions down the . For example, with a left shift of 3, D would be replaced by A, E would become B, and so on. The method is named after , who used it in his private correspondence.
The encryption step performed by a Caesar cipher is often incorporated as part of more complex schemes, such as the , and still has modern application in the
system. As with all single-alphabet substitution ciphers, the Caesar cipher is easily broken and in modern practice offers essentially no .
The transformation can be represented by al the cipher alphabet is the plain alphabet rotated left or right by some number of positions. For instance, here is a Caesar cipher using a left rotation of three places, equivalent to a right shift of 23 (the shift parameter is used as the ):
ABCDEFGHIJKLMNOPQRSTUVWXYZ
XYZABCDEFGHIJKLMNOPQRSTUVW
When encrypting, a person looks up each letter of the message in the "plain" line and writes down the corresponding letter in the "cipher" line.
Plaintext:
THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG
Ciphertext: QEB NRFZH YOLTK CLU GRJMP LSBO QEB IXWV ALD
Deciphering is done in reverse, with a right shift of 3.
The encryption can also be represented using
by first transforming the letters into numbers, according to the scheme, A → 0, B → 1, ..., Z → 25. Encryption of a letter x by a shift n can be described mathematically as,
{\displaystyle E_{n}(x)=(x+n)\mod {26}.}
Decryption is performed similarly,
{\displaystyle D_{n}(x)=(x-n)\mod {26}.}
(There are different definitions for the . In the above, the result is in the range 0 to 25; i.e., if x + n or x - n are not in the range 0 to 25, we have to subtract or add 26.)
The replacement remains the same throughout the message, so the cipher is classed as a type of , as opposed to .
The Caesar cipher is named for , who used an alphabet with a left shift of three.
The Caesar cipher is named after , who, according to , used it with a shift of three to protect messages of military significance. While Caesar's was the first recorded use of this scheme, other substitution ciphers are known to have been used earlier.
"If he had anything confidential to say, he wrote it in cipher, that is, by so changing the order of the letters of the alphabet, that not a word could be made out. If anyone wishes to decipher these, and get at their meaning, he must substitute the fourth letter of the alphabet, namely D, for A, and so with the others."
His nephew, , also used the cipher, but with a right shift of one, and it did not wrap around to the beginning of the alphabet:
"Whenever he wrote in cipher, he wrote B for A, C for B, and the rest of the letters on the same principle, using AA for Z."
Evidence exists that Julius Caesar also used more complicated systems, and one writer, , refers to a (now lost) treatise on his ciphers:
"There is even a rather ingeniously written treatise by the grammarian Probus concerning the secret meaning of letters in the composition of Caesar's epistles."
— , Attic Nights 17.9.1–5
It is unknown how effective the Caesar cipher was at the time, but it is likely to have been reasonably secure, not least because most of Caesar's enemies would have been
and others would have assumed that the messages were written in an unknown foreign language. There is no record at that time of any techniques for the solution of simple substitution ciphers. The earliest surviving records date to the 9th century works of
world with the discovery of .
A Caesar cipher with a shift of one is used on the back of the
to encrypt the . This may be a holdover from an earlier time when Jewish people were not allowed to have mezuzot. The letters of the cryptogram themselves comprise a religiously significant "divine name" which
belief holds keeps the forces of evil in check.
In the 19th century, the personal advertisements section in newspapers would sometimes be used to exchange messages encrypted using simple cipher schemes.
(1967) describes instances of lovers engaging in secret communications enciphered using the Caesar cipher in . Even as late as 1915, the Caesar cipher was in use: the Russian army employed it as a replacement for more complicated ciphers which had proved to be too difficult for th German and Austrian cryptanalysts had little difficulty in decrypting their messages.
Caesar ciphers can be found today in children's toys such as . A Caesar shift of thirteen is also performed in the
, a simple method of obfuscating text widely found on
and used to obscure text (such as joke punchlines and story ), but not seriously used as a method of encryption.
A construction of 2 rotating disks with a Caesar cipher can be used to encrypt or decrypt the code.
uses a Caesar cipher with a different shift at each
the value of the shift is defined using a repeating keyword. If the keyword is as long as the message, chosen , never becomes known to anyone else, and is never reused, this is the
cipher, proven unbreakable. The conditions are so difficult they are, in practical effect, never achieved. Keywords shorter than the message (e.g., "" used by the
during the ), introduce a cyclic pattern that might be detected with a statistically advanced version of frequency analysis.
In April 2006, fugitive
was captured in
partly because some of his messages, clumsily written in a variation of the Caesar cipher, were broken. Provenzano's cipher used numbers, so that "A" would be written as "4", "B" as "5", and so on.
In 2011, Rajib Karim was convicted in the United Kingdom of "terrorism offences" after using the Caesar cipher to communicate with Bangladeshi Islamic activists discussing plots to blow up
planes or disrupt their IT networks. Although the parties had access to far better encryption techniques (Karim himself used
for data storage on computer disks), they chose to use their own scheme (implemented in ), rejecting a more sophisticated code program called Mujhaddin Secrets "because 'kaffirs', or non-believers, know about it, so it must be less secure".
Decryption
Candidate plaintext
exxegoexsrgi
dwwdfndwrqfh
cvvcemcvqpeg
buubdlbupodf
attackatonce
zsszbjzsnmbd
yrryaiyrmlac
haahjrhavujl
gzzgiqgzutik
fyyfhpfytshj
The Caesar cipher can be easily broken even in a . Two situations can be considered:
an attacker knows (or guesses) that some sort of simple substitution cipher has been used, but not specifically that it is a C
an attacker knows that a Caesar cipher is in use, but does not know the shift value.
In the first case, the cipher can be broken using the same techniques as for a general simple substitution cipher, such as
or pattern words. While solving, it is likely that an attacker will quickly notice the regularity in the solution and deduce that a Caesar cipher is the specific algorithm employed.
The distribution of letters in a typical sample of English language text has a distinctive and predictable shape. A Caesar shift "rotates" this distribution, and it is possible to determine the shift by examining the resultant frequency graph.
In the second instance, breaking the scheme is even more straightforward. Since there are only a limited number of possible shifts (26 in English), they can each be tested in turn in a . One way to do this is to write out a snippet of the ciphertext in a table of all possible shifts – a technique sometimes known as "completing the plain component". The example given is for the ciphertext "EXXEGOEXSRGI"; the plaintext is instantly recognisable by eye at a shift of four. Another way of viewing this method is that, under each letter of the ciphertext, the entire alphabet is written out in reverse starting at that letter. This attack can be accelerated using a set of strips prepared with the alphabet written down in reverse order. The strips are then aligned to form the ciphertext along one row, and the plaintext should appear in one of the other rows.
Another brute force approach is to match up the frequency distribution of the letters. By graphing the frequencies of letters in the ciphertext, and by knowing the expected distribution of those letters in the original language of the plaintext, a human can easily spot the value of the shift by looking at the displacement of particular features of the graph. This is known as . For example, in the English language the plaintext frequencies of the letters E, T, (usually most frequent), and Q, Z (typically least frequent) are particularly distinctive. Computers can also do this by measuring how well the actual frequency distribution matches up with the e for example, the
can be used.
For natural language plaintext, there will typically be only one plausible decryption, although for extremely short plaintexts, multiple candidates are possible. For example, the ciphertext MPQY could, plausibly, decrypt to either "" or "know" (assuming the plaintext is in English); similarly, "ALIIP" to "dolls" or "wheel"; and "AFCCP" to "jolly" or "cheer" (see also ).
With the Caesar cipher, encrypting a text multiple times provides no additional security. This is because two encryptions of, say, shift A and shift B, will be equivalent to a single encryption with shift A + B. In mathematical terms, the set of encryption operations under each possible key forms a
Suetonius,
Luciano, D Gordon Prichett (January 1987). "Cryptology: From Caesar Ciphers to Public-Key Cryptosystems". The College Mathematics Journal. 18 (1): 2–17.   . :.  .
Wobst, Reinhard (2001). Cryptology Unlocked. Wiley. p. 19.  .
. Central Intelligence Agency 2017.
(2000). . Anchor. pp. 289–290.  .
Reinke, Edgar C. (December 1992). "Classical Cryptography". The Classical Journal. 58 (3): 114.
Pieprzyk, J Thomas H Jennifer Seberry (2003). Fundamentals of Computer Security. Springer. p. 6.  .
(2000). . Anchor. pp. 14–20.  .
Alexander Poltorak. . .
(1967). The Codebreakers. pp. 775–6.  .
(1967). The Codebreakers. pp. 631–2.  .
Wobst, Reinhard (2001). Cryptology Unlocked. Wiley. p. 20.  .
(1967). The Codebreakers.  .
Leyden, John (). . .
(1994). Cryptology. . pp. 9–11.  .
(1994). Cryptology. . pp. 8–9.  .
Leighton, Albert C. (April 1969). "Secret Communication among the Greeks and Romans". Technology and Culture. 10 (2): 139–154. :.  .
; Paul L. Irwin (1966). Elementary Cryptanalysis: A Mathematical Approach. Mathematical Association of America. pp. 13–15.  .
(2000). The Code Book. Anchor. pp. 72–77.  .
Savarese, C Brian Hart (). .
Wobst, Reinhard (2001). Cryptology Unlocked. Wiley. p. 31.  .
, The Codebreakers – The Story of Secret Writing, Revised ed. 1996.  .
, Decrypted Secrets, 2nd edition, 2000, Springer.  .
Chris Savarese and Brian Hart, , 1999
This audio file was created from a revision of the article "Caesar cipher" dated , and does not reflect subsequent edits to the article. ()
: Hidden categories:julius ceasar 属于哪个家族的_百度知道
julius ceasar 属于哪个家族的
我有更好的答案
我的尾数是2，司文家族 特征：温文尔雅，书卷味很强，完美主义者优点：心思细腻，心性平和 传说司文家族是天神身旁的得力助手,这个家族的成员从一出身的时候身上就隐藏着神秘的辅佐力量,当天地还是初开的时候,这个家族的人散落在茫茫宇宙中,但天神从世界之镜中找到他们,并且让他们各归其位,各司其责。 这个家族的成员个个俊美无比,温文尔雅,因为负责的大多属于文职,所以书卷味很浓烈。他们在对待事情方面是个完美主义者,不管是在对待事业还是在爱情方面都是如此。因为完美或许会有些孤寂,不过他们身上强烈的磁场会吸引着他们的幸福一步步的接近他们。命运的齿轮会再次转动,幸福的光芒将会笼罩着整个司文家族。
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Twenty-year-old Julius Caeser flees Rome for his life during the reign of Sulla, but through skill and ambition rises four decades later to become Rome's supreme dictator.
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Julius Caesar
(TV Movie 2002)
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Nominated for
Primetime Emmys.
2 wins & 2 nominations.
Caesar Augustus tells of how he became the emperor to his reluctant daughter, Julia following the death of her husband Agrippa.
Roger Young
Peter O'Toole,
Charlotte Rampling,
Vittoria Belvedere
It is 200 years before the birth of Christ and Rome is the new superpower of the ancient world. She believes she is invincible - but one man is destined to change that. He is a man bound by...
Edward Bazalgette
Alexander Siddig,
Emilio Doorgasingh,
Bashar Rahal
A thirteen hour series which focuses on the Germanic, Britannic and other barbarian tribal wars with Rome which ultimately led to the decline and fall of the Roman Empire. This series is ...
Leif Anders,
Paul Bicknell,
Andre de Nesnera
Epic four-hour series about the rise of Octavius who succeeds Julius Caesar and tangles with Marc Anthony for control of the Roman empire and finally went on to become the emperor Augustus.
Santiago Cabrera,
Vincent Regan,
Emily Blunt
The growing ambition of Julius Caesar is a source of major concern to his close friend Brutus. Cassius persuades him to participate in his plot to assassinate Caesar but they have both sorely underestimated Mark Antony.
Joseph L. Mankiewicz
Louis Calhern,
Marlon Brando,
James Mason
The growing ambition of Julius Caesar is a source of major concern to his close friend Brutus. Cassius persuades him to participate in his plot to assassinate Caesar but they have both sorely underestimated Mark Antony.
Stuart Burge
Charlton Heston,
Jason Robards,
John Gielgud
A six-episode mini-series covering five centuries of the Roman Empire.
Paul Marcus
Hans Matheson,
Laura Morante,
Rike Schmid
The growing ambition of Julius Caesar is a source of major concern to his close friend Brutus. Cassius persuades him to participate in his plot to assassinate Caesar but they have both sorely underestimated Mark Antony.
Gregory Doran
Theo Affail,
Segun Akingbola,
Adjoa Andoh
A romanced story of Attila the Hun, from when he lost his parents in childhood until his death. Attila is disclosed as a great leader, strategist and lover and the movie shows his respect ...
Pauline Lynch,
Steven Berkoff,
Andrew Pleavin
A doc-drama covering the rise and the fall of the Roman world including the founding by Julius Caesar and the building of Rome by Nero.
Lyall B. Watson,
James D'Arcy,
Sean Pertwee
Princess Cleopatra becomes Egypt's Queen and has an out-of-wedlock son with the son-less Roman ruler Julius Ceasar. Through two romances, she strives to protect Egypt from the Romans, and make her son the heir to Ceaser's Roman Empire.
Nadim Sawalha,
Owen Teale,
Philip Quast
William Shakespeare's epic tale of conspiracy, loyalty and betrayal. Rome is destroyed, their world has crumbled, but life must go on. Survival drives people in a broken world, where ...
Directors:
Adam Lee Hamilton,
John Montegrande
Jordan Daws,
Paul Syrstad,
Saul Matlock
Cast overview, first billed only:
(as Christopher Noth)
Vercingetorix
Marcus Portius
Epic look at Julius Caesar, Rome's last dictator, whose death also signaled the end of the Roman Republic. Chronicles his campaigns in Gaul and Egypt, his rivalry with General Pompey, and his eventual assassination at the hands of Brutus and Cassius.
Written by
Plot Keywords:
Feared by enemies. Betrayed by friends.
Motion Picture Rating
Rated PG-13 for sequences of violence, and some sensuality
Parents Guide:
Official Sites:
Release Date: 27 December 2002 (Germany)
Also Known As: Júlio César
Filming Locations:
Budget:$20,000,000
(estimated)
Production Co:
Show more on
Sound Mix:
Aspect Ratio: 1.33 : 1
Did You Know?
spent five hours daily in make-up and wardrobe to transform him into Vercingetorix.
When Caeser was forced to leave Rome during the dictatorship of Sulla in 82 B.C., he was 20 years old, yet the film shows him as having an approximately twelve year-old daughter.
There's a lot of Rome still out there, it just isn't called Rome yet.
Connections
Featured in &(2017)
Frequently Asked Questions
User Reviews
I'm glad I watched this because my knowledge of Roman history is so spotty that I learned something from it. I knew Caesar crossed the Rubicon but didn't know when, or why it was important. I knew Caesar was assassinated, and that Cato fell on his sword, and Cleopatra seduced Caesar and all that, but that's common knowledge. I didn't know that Cato falling on his sword had anything to do with Caesar's triumphant return to Rome after defeating the Roman army under Pompey. I'd never been entirely clear who Pompey was, for that matter, except that it was the name of a Roman general and a slave who accompanied Lewis and Clark on their vacation and also the name of John Wayne's assistant in &The Man Who Shot Liberty Valence&.So this pulled a lot of things together for me, as history. If I had a problem with it, it was that I had a tough time keeping the characters straight. They weren't frequently enough called by name. And since most of the faces were unfamiliar the problem was even more acute.I did recognize Richard Harris, looking absolutely GREAT in his last film role, all white and withered and glowing with inner strength and with nastiness. And Chris Noth I recognized from the early episodes of &Law and Order.& He did pretty well as Pompeii, although his speech had a Brit accent that tended to come and go. Christopher Walken was both recognizable and rememberable as Cato. He's a surprisingly versatile actor. Valeria Golena was also a familiar face as Calpurnia, Caesar's second wife. (I never knew he had a first one. See what I mean?) And -- triumph of all triumphs -- I finally learned how to pronounce the name of Vercingetorix, the Arverni chieftain who led the Gauls. Speaking of him -- VercinGETorix, that is -- the actor who plays him, and whose name I don't have the opportunity to look up at the moment, gives what is for me the best performance in the movie. He is a brave, self-sacrificing, and dignified man (for a Barbarian) and the actor captures all these attributes, and has a sympatico face to boot, though by no means a handsome one. As portrayed here, if he had just been born in Gaul two millenia later, I could visualize him in an inexpensive suit dining on medallions of beef in some unpretentious bistro, with a glass of Ch?teau Neuf du Pape, using the continental knife and fork technique. As it is, he gets his head lopped off.The story is a little confusing though. I suppose you can't stuff all of Caesar's life story into a few hours. But I missed the final confrontation between Caesar's outnumbered army and Pompey's in Egypt. We see Caesar leaving Rome with a determined expression, and the next thing we know he and his men are in Pompey's tent at Pharsalus. We are also told that Pompey's head was chopped off by the Egyptians at Alexandria, whereas some sources claim it was done by traitors among Pompey's men. It is also not entirely clear to me why some of these guys are considered military geniuses. We only get to see a single map. Pompey leaves Rome early in Part I and returns a hero. Okay. What did he do that was so hot? And we see Caesar defeat a horde of Gauls. He must have done more than that, but what? A few more maps, or exposition in some other form, however clumsy, might have helped. It's also not made clear enough that Caesar committed an illegal act, a surprise for a guy who is shown to be so fair and compassionate and, if not exactly self-effacing, at least no egomaniac. Rome was a Republic, ruled by the Senate. It was governed by laws. The Senate ordered Caesar to disband his army and return to Rome or else be declared a traitor. By Roman law no general could bring his forces into Italy proper without the consent of the Senate. The border of Italy was the Rubicon and Caesar took his legions across it in defiance of the Senate, saying, &The die is cast.& Hearing this, Pompey and some of the Senate took off for friendlier climes because Caesar by this time had a huge force with him. When he entered Rome, what was left of the Senate appointed him dictator. End of the Republic. That wasn't very nice, was it? Oh, and another thing -- I always thought that when a Roman general returned from a victory, trailing prisoners and booty, a slave stood beside him in the chariot whispering to him, &Remember, thou art mortal,& just so he didn't get any ideas like Caesar did.I wish some of the performances had been better. Many of them are pretty weak, Mark Antony in particular. And Brutus seems too young for the part, and he's the one who looks &sicklied o'er with the pale cast of thought.& In fact, he really IS pale and sweaty and a nervous wreck. The Roman Empire finally fell apart, as everyone knows, but as it split up, there were still a lot of leaders or would-be leaders claiming direct descent from Gaius Julius Caesar. They were with us until just recently. The Tsar (or Czar) of Russia bore the title of Caesar, which is where the Russian word comes from. In Germany, &Caesar& became Kaiser, as in Kaiser Wilhelm. Too bad we didn't get more of Caesar's accomplishments, or a better look at his weaknesses -- after all, he allowed himself to be appointed dictator without trying to reconstitute the Senate -- and there was that business with Cleopatra, a political opportunist if there ever was one. Still, it's worth watching. It's an interesting historical tale.
10 of 21 people found this review helpful.&
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