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Caesar cipher

Caesar cipher, is one of the simplest and most widely known encryption techniques. The transformation can be represented by aligning two alphabets, the cipher alphabet is the plain alphabet rotated left or right by some number of positions.

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. Deciphering is done in reverse.
The encryption can also be represented using modular arithmetic 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

Plaintext: cesari
cipher variations:
dftbsj eguctk fhvdul giwevm hjxfwn
ikygxo jlzhyp kmaizq lnbjar mockbs
npdlct oqemdu prfnev qsgofw rthpgx
suiqhy tvjriz uwksja vxltkb wymulc
xznvmd yaowne zbpxof acqypg bdrzqh

Decryption is performed similarly,

(There are different definitions for the modulo operation. In the above, the result is in the range 0...25. I.e., if x+n or x-n are not in the range 0...25, we have to subtract or add 26.)
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Atbash Cipher

Atbash is an ancient encryption system created in the Middle East. It was originally used in the Hebrew language.
The Atbash cipher is a simple substitution cipher that relies on transposing all the letters in the alphabet such that the resulting alphabet is backwards.
The first letter is replaced with the last letter, the second with the second-last, and so on.
An example plaintext to ciphertext using Atbash:
Plain: cesari
Cipher: xvhzir

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Baconian Cipher

To encode a message, each letter of the plaintext is replaced by a group of five of the letters 'A' or 'B'. This replacement is done according to the alphabet of the Baconian cipher, shown below.
a   AAAAA   g    AABBA     m    ABABB   s    BAAAB     y    BABBA
b   AAAAB   h    AABBB     n    ABBAA   t    BAABA     z    BABBB
c   AAABA   i    ABAAA     o    ABBAB   u    BAABB 
d   AAABB   j    BBBAA     p    ABBBA   v    BBBAB
e   AABAA   k    ABAAB     q    ABBBB   w    BABAA
f   AABAB   l    ABABA     r    BAAAA   x    BABAB

Plain: cesari

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Affine Cipher
In the affine cipher the letters of an alphabet of size m are first mapped to the integers in the range 0..m - 1. It then uses modular arithmetic to transform the integer that each plaintext letter corresponds to into another integer that correspond to a ciphertext letter. The encryption function for a single letter is

where modulus m is the size of the alphabet and a and b are the key of the cipher. The value a must be chosen such that a and m are coprime.
Considering the specific case of encrypting messages in English (i.e. m = 26), there are a total of 286 non-trivial affine ciphers, not counting the 26 trivial Caesar ciphers. This number comes from the fact there are 12 numbers that are coprime with 26 that are less than 26 (these are the possible values of a). Each value of a can have 26 different addition shifts (the b value) ; therefore, there are 12*26 or 312 possible keys.
Plaintext: cesari
cipher variations:

The decryption function is

where a - 1 is the modular multiplicative inverse of a modulo m. I.e., it satisfies the equation

The multiplicative inverse of a only exists if a and m are coprime. Hence without the restriction on a decryption might not be possible. It can be shown as follows that decryption function is the inverse of the encryption function,

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ROT13 Cipher
Applying ROT13 to a piece of text merely requires examining its alphabetic characters and replacing each one by the letter 13 places further along in the alphabet, wrapping back to the beginning if necessary. A becomes N, B becomes O, and so on up to M, which becomes Z, then the sequence continues at the beginning of the alphabet: N becomes A, O becomes B, and so on to Z, which becomes M. Only those letters which occur in the English alphabet are affected; numbers, symbols, whitespace, and all other characters are left unchanged. Because there are 26 letters in the English alphabet and 26 = 2 * 13, the ROT13 function is its own inverse:

ROT13(ROT13(x)) = x for any basic Latin-alphabet text x

An example plaintext to ciphertext using ROT13:

Plain: cesari
Cipher: prfnev

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Polybius Square

A Polybius Square is a table that allows someone to translate letters into numbers. To give a small level of encryption, this table can be randomized and shared with the recipient. In order to fit the 26 letters of the alphabet into the 25 spots created by the table, the letters i and j are usually combined.
1 2 3 4 5
1 A B C D E
2 F G H I/J K
3 L M N O P
4 Q R S T U
5 V W X Y Z

Basic Form:
Plain: cesari
Cipher: 315134112442

Extended Methods:
Method #1

Plaintext: cesari
method variations:

Method #2
Bifid cipher
The message is converted to its coordinates in the usual manner, but they are written vertically beneath:
c e s a r i 
3 5 3 1 2 4 
1 1 4 1 4 2 
They are then read out in rows:
Then divided up into pairs again, and the pairs turned back into letters using the square:
Plain: cesari
Cipher: xcradi

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Method #3

Plaintext: cesari
method variations:
vldftm ldftmv dftmvl
ftmvld tmvldf mvldft

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Permutation Cipher
In classical cryptography, a permutation cipher is a transposition cipher in which the key is a permutation. To apply a cipher, a random permutation of size E is generated (the larger the value of E the more secure the cipher). The plaintext is then broken into segments of size E and the letters within that segment are permuted according to this key.
In theory, any transposition cipher can be viewed as a permutation cipher where E is equal to the length of the plaintext; this is too cumbersome a generalisation to use in actual practice, however.
The idea behind a permutation cipher is to keep the plaintext characters unchanged, butalter their positions by rearrangement using a permutation
This cipher is defined as:
Let m be a positive integer, and K consist of all permutations of {1,...,m}
For a key (permutation) , define:
The encryption function
The decryption function
A small example, assuming m = 6, and the key is the permutation :

The first row is the value of i, and the second row is the corresponding value of (i)
The inverse permutation, is constructed by interchanging the two rows, andrearranging the columns so that the first row is in increasing order, Therefore, is:

Total variation formula:

e = 2,718281828 , n - plaintext length

Plaintext: cesari

all 720 cipher variations:
cesari cesair cesrai cesria cesira cesiar ceasri ceasir cearsi cearis ceairs
ceaisr cerasi cerais cersai cersia cerisa cerias ceiars ceiasr ceiras ceirsa
ceisra ceisar cseari cseair cserai cseria cseira cseiar csaeri csaeir csarei
csarie csaire csaier csraei csraie csreai csreia csriea csriae csiare csiaer
csirae csirea csiera csiear caseri caseir casrei casrie casire casier caesri
caesir caersi caeris caeirs caeisr caresi careis carsei carsie carise caries
caiers caiesr caires cairse caisre caiser crsaei crsaie crseai crseia crsiea
crsiae crasei crasie craesi craeis craies craise creasi creais cresai cresia
creisa creias criaes criase crieas criesa crisea crisae cisare cisaer cisrae
cisrea cisera cisear ciasre ciaser ciarse ciares ciaers ciaesr cirase ciraes
cirsae cirsea ciresa cireas ciears cieasr cieras ciersa ciesra ciesar ecsari
ecsair ecsrai ecsria ecsira ecsiar ecasri ecasir ecarsi ecaris ecairs ecaisr
ecrasi ecrais ecrsai ecrsia ecrisa ecrias eciars eciasr eciras ecirsa ecisra
ecisar escari escair escrai escria escira esciar esacri esacir esarci esaric
esairc esaicr esraci esraic esrcai esrcia esrica esriac esiarc esiacr esirac
esirca esicra esicar eascri eascir easrci easric easirc easicr eacsri eacsir
eacrsi eacris eacirs eacisr earcsi earcis earsci earsic earisc earics eaicrs
eaicsr eaircs eairsc eaisrc eaiscr ersaci ersaic erscai erscia ersica ersiac
erasci erasic eracsi eracis eraics eraisc ercasi ercais ercsai ercsia ercisa
ercias eriacs eriasc ericas ericsa erisca erisac eisarc eisacr eisrac eisrca
eiscra eiscar eiasrc eiascr eiarsc eiarcs eiacrs eiacsr eirasc eiracs eirsac
eirsca eircsa eircas eicars eicasr eicras eicrsa eicsra eicsar secari secair
secrai secria secira seciar seacri seacir searci searic seairc seaicr seraci
seraic sercai sercia serica seriac seiarc seiacr seirac seirca seicra seicar
sceari sceair scerai sceria sceira sceiar scaeri scaeir scarei scarie scaire
scaier scraei scraie screai screia scriea scriae sciare sciaer scirae scirea
sciera sciear saceri saceir sacrei sacrie sacire sacier saecri saecir saerci
saeric saeirc saeicr sareci sareic sarcei sarcie sarice sariec saierc saiecr
sairec sairce saicre saicer srcaei srcaie srceai srceia srciea srciae sracei
sracie sraeci sraeic sraiec sraice sreaci sreaic srecai srecia sreica sreiac
sriaec sriace srieac srieca sricea sricae sicare sicaer sicrae sicrea sicera
sicear siacre siacer siarce siarec siaerc siaecr sirace siraec sircae sircea
sireca sireac siearc sieacr sierac sierca siecra siecar aescri aescir aesrci
aesric aesirc aesicr aecsri aecsir aecrsi aecris aecirs aecisr aercsi aercis
aersci aersic aerisc aerics aeicrs aeicsr aeircs aeirsc aeisrc aeiscr asecri
asecir aserci aseric aseirc aseicr asceri asceir ascrei ascrie ascire ascier
asrcei asrcie asreci asreic asriec asrice asicre asicer asirce asirec asierc
asiecr acseri acseir acsrei acsrie acsire acsier acesri acesir acersi aceris
aceirs aceisr acresi acreis acrsei acrsie acrise acries aciers aciesr acires
acirse acisre aciser arscei arscie arseci arseic arsiec arsice arcsei arcsie
arcesi arceis arcies arcise arecsi arecis aresci aresic areisc areics arices
aricse ariecs ariesc arisec arisce aiscre aiscer aisrce aisrec aiserc aisecr
aicsre aicser aicrse aicres aicers aicesr aircse airces airsce airsec airesc
airecs aiecrs aiecsr aiercs aiersc aiesrc aiescr resaci resaic rescai rescia
resica resiac reasci reasic reacsi reacis reaics reaisc recasi recais recsai
recsia recisa recias reiacs reiasc reicas reicsa reisca reisac rseaci rseaic
rsecai rsecia rseica rseiac rsaeci rsaeic rsacei rsacie rsaice rsaiec rscaei
rscaie rsceai rsceia rsciea rsciae rsiace rsiaec rsicae rsicea rsieca rsieac
raseci raseic rascei rascie rasice rasiec raesci raesic raecsi raecis raeics
raeisc racesi raceis racsei racsie racise racies raiecs raiesc raices raicse
raisce raisec rcsaei rcsaie rcseai rcseia rcsiea rcsiae rcasei rcasie rcaesi
rcaeis rcaies rcaise rceasi rceais rcesai rcesia rceisa rceias rciaes rciase
rcieas rciesa rcisea rcisae risace risaec riscae riscea riseca riseac riasce
riasec riacse riaces riaecs riaesc ricase ricaes ricsae ricsea ricesa riceas
rieacs rieasc riecas riecsa riesca riesac iesarc iesacr iesrac iesrca iescra
iescar ieasrc ieascr iearsc iearcs ieacrs ieacsr ierasc ieracs iersac iersca
iercsa iercas iecars iecasr iecras iecrsa iecsra iecsar isearc iseacr iserac
iserca isecra isecar isaerc isaecr isarec isarce isacre isacer israec israce
isreac isreca isrcea isrcae iscare iscaer iscrae iscrea iscera iscear iaserc
iasecr iasrec iasrce iascre iascer iaesrc iaescr iaersc iaercs iaecrs iaecsr
iaresc iarecs iarsec iarsce iarcse iarces iacers iacesr iacres iacrse iacsre
iacser irsaec irsace irseac irseca irscea irscae irasec irasce iraesc iraecs
iraces iracse ireasc ireacs iresac iresca irecsa irecas ircaes ircase irceas
ircesa ircsea ircsae icsare icsaer icsrae icsrea icsera icsear icasre icaser
icarse icares icaers icaesr icrase icraes icrsae icrsea icresa icreas icears
iceasr iceras icersa icesra icesar

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