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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: serina
cipher variations:
tfsjob ugtkpc vhulqd wivmre xjwnsf
ykxotg zlypuh amzqvi bnarwj cobsxk
dpctyl eqduzm frevan gsfwbo htgxcp
iuhydq jvizer kwjafs lxkbgt mylchu
nzmdiv oanejw pbofkx qcpgly rdqhmz

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: serina
Cipher: hvirmz

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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: serina

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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: serina
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: serina
Cipher: frevan

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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: serina
Cipher: 345124423311

Extended Methods:
Method #1

Plaintext: serina
method variations:

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

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Method #3

Plaintext: serina
method variations:
yftmcl ftmcly tmclyf
mclyft clyftm lyftmc

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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: serina

all 720 cipher variations:
serina serian sernia sernai serani serain seirna seiran seinra seinar seianr
seiarn senira seniar senria senrai senari senair seainr seairn seanir seanri
searni searin sreina sreian srenia srenai sreani sreain sriena sriean srinea
srinae sriane sriaen srniea srniae srneia srneai srnaei srnaie sraine sraien
sranie sranei sraeni sraein sirena sirean sirnea sirnae sirane siraen sierna
sieran sienra sienar sieanr siearn sinera sinear sinrea sinrae sinare sinaer
siaenr siaern sianer sianre siarne siaren snriea snriae snreia snreai snraei
snraie snirea snirae sniera sniear sniaer sniare sneira sneiar sneria snerai
sneari sneair snaier snaire snaeir snaeri snarei snarie sarine sarien sarnie
sarnei sareni sarein sairne sairen sainre sainer saienr saiern sanire sanier
sanrie sanrei saneri saneir saeinr saeirn saenir saenri saerni saerin esrina
esrian esrnia esrnai esrani esrain esirna esiran esinra esinar esianr esiarn
esnira esniar esnria esnrai esnari esnair esainr esairn esanir esanri esarni
esarin ersina ersian ersnia ersnai ersani ersain erisna erisan erinsa erinas
erians eriasn ernisa ernias ernsia ernsai ernasi ernais erains eraisn eranis
eransi erasni erasin eirsna eirsan eirnsa eirnas eirans eirasn eisrna eisran
eisnra eisnar eisanr eisarn einsra einsar einrsa einras einars einasr eiasnr
eiasrn eiansr eianrs eiarns eiarsn enrisa enrias enrsia enrsai enrasi enrais
enirsa eniras enisra enisar eniasr eniars ensira ensiar ensria ensrai ensari
ensair enaisr enairs enasir enasri enarsi enaris earins earisn earnis earnsi
earsni earsin eairns eairsn eainrs eainsr eaisnr eaisrn eanirs eanisr eanris
eanrsi eansri eansir easinr easirn easnir easnri easrni easrin resina resian
resnia resnai resani resain reisna reisan reinsa reinas reians reiasn renisa
renias rensia rensai renasi renais reains reaisn reanis reansi reasni reasin
rseina rseian rsenia rsenai rseani rseain rsiena rsiean rsinea rsinae rsiane
rsiaen rsniea rsniae rsneia rsneai rsnaei rsnaie rsaine rsaien rsanie rsanei
rsaeni rsaein risena risean risnea risnae risane risaen riesna riesan riensa
rienas rieans rieasn rinesa rineas rinsea rinsae rinase rinaes riaens riaesn
rianes rianse riasne riasen rnsiea rnsiae rnseia rnseai rnsaei rnsaie rnisea
rnisae rniesa rnieas rniaes rniase rneisa rneias rnesia rnesai rneasi rneais
rnaies rnaise rnaeis rnaesi rnasei rnasie rasine rasien rasnie rasnei raseni
rasein raisne raisen rainse raines raiens raiesn ranise ranies ransie ransei
ranesi raneis raeins raeisn raenis raensi raesni raesin iersna iersan iernsa
iernas ierans ierasn iesrna iesran iesnra iesnar iesanr iesarn iensra iensar
ienrsa ienras ienars ienasr ieasnr ieasrn ieansr ieanrs iearns iearsn iresna
iresan irensa irenas ireans ireasn irsena irsean irsnea irsnae irsane irsaen
irnsea irnsae irnesa irneas irnaes irnase irasne irasen iranse iranes iraens
iraesn isrena isrean isrnea isrnae israne israen iserna iseran isenra isenar
iseanr isearn isnera isnear isnrea isnrae isnare isnaer isaenr isaern isaner
isanre isarne isaren inrsea inrsae inresa inreas inraes inrase insrea insrae
insera insear insaer insare inesra inesar inersa ineras inears ineasr inaser
inasre inaesr inaers inares inarse iarsne iarsen iarnse iarnes iarens iaresn
iasrne iasren iasnre iasner iasenr iasern iansre ianser ianrse ianres ianers
ianesr iaesnr iaesrn iaensr iaenrs iaerns iaersn nerisa nerias nersia nersai
nerasi nerais neirsa neiras neisra neisar neiasr neiars nesira nesiar nesria
nesrai nesari nesair neaisr neairs neasir neasri nearsi nearis nreisa nreias
nresia nresai nreasi nreais nriesa nrieas nrisea nrisae nriase nriaes nrsiea
nrsiae nrseia nrseai nrsaei nrsaie nraise nraies nrasie nrasei nraesi nraeis
niresa nireas nirsea nirsae nirase niraes niersa nieras niesra niesar nieasr
niears nisera nisear nisrea nisrae nisare nisaer niaesr niaers niaser niasre
niarse niares nsriea nsriae nsreia nsreai nsraei nsraie nsirea nsirae nsiera
nsiear nsiaer nsiare nseira nseiar nseria nserai nseari nseair nsaier nsaire
nsaeir nsaeri nsarei nsarie narise naries narsie narsei naresi nareis nairse
naires naisre naiser naiesr naiers nasire nasier nasrie nasrei naseri naseir
naeisr naeirs naesir naesri naersi naeris aerins aerisn aernis aernsi aersni
aersin aeirns aeirsn aeinrs aeinsr aeisnr aeisrn aenirs aenisr aenris aenrsi
aensri aensir aesinr aesirn aesnir aesnri aesrni aesrin areins areisn arenis
arensi aresni aresin ariens ariesn arines arinse arisne arisen arnies arnise
arneis arnesi arnsei arnsie arsine arsien arsnie arsnei arseni arsein airens
airesn airnes airnse airsne airsen aierns aiersn aienrs aiensr aiesnr aiesrn
ainers ainesr ainres ainrse ainsre ainser aisenr aisern aisner aisnre aisrne
aisren anries anrise anreis anresi anrsei anrsie anires anirse aniers aniesr
aniser anisre aneirs aneisr aneris anersi anesri anesir ansier ansire anseir
anseri ansrei ansrie asrine asrien asrnie asrnei asreni asrein asirne asiren
asinre asiner asienr asiern asnire asnier asnrie asnrei asneri asneir aseinr
aseirn asenir asenri aserni aserin

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