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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: jambos
cipher variations:
kbncpt lcodqu mdperv neqfsw ofrgtx
pgshuy qhtivz riujwa sjvkxb tkwlyc
ulxmzd vmynae wnzobf xoapcg ypbqdh
zqcrei ardsfj bsetgk ctfuhl dugvim
evhwjn fwixko gxjylp hykzmq izlanr

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: jambos
Cipher: qznylh

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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: jambos

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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: jambos
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: jambos
Cipher: wnzobf

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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: jambos
Cipher: 421123214334

Extended Methods:
Method #1

Plaintext: jambos
method variations:

Method #2
Bifid cipher
The message is converted to its coordinates in the usual manner, but they are written vertically beneath:
j a m b o s 
4 1 2 2 4 3 
2 1 3 1 3 4 
They are then read out in rows:
Then divided up into pairs again, and the pairs turned back into letters using the square:
Plain: jambos
Cipher: dgobcs

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Method #3

Plaintext: jambos
method variations:
bfhqnt fhqntb hqntbf
qntbfh ntbfhq tbfhqn

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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: jambos

all 720 cipher variations:
jambos jambso jamobs jamosb jamsob jamsbo jabmos jabmso jaboms jabosm jabsom
jabsmo jaobms jaobsm jaombs jaomsb jaosmb jaosbm jasbom jasbmo jasobm jasomb
jasmob jasmbo jmabos jmabso jmaobs jmaosb jmasob jmasbo jmbaos jmbaso jmboas
jmbosa jmbsoa jmbsao jmobas jmobsa jmoabs jmoasb jmosab jmosba jmsboa jmsbao
jmsoba jmsoab jmsaob jmsabo jbmaos jbmaso jbmoas jbmosa jbmsoa jbmsao jbamos
jbamso jbaoms jbaosm jbasom jbasmo jboams jboasm jbomas jbomsa jbosma jbosam
jbsaom jbsamo jbsoam jbsoma jbsmoa jbsmao jombas jombsa jomabs jomasb jomsab
jomsba jobmas jobmsa jobams jobasm jobsam jobsma joabms joabsm joambs joamsb
joasmb joasbm josbam josbma josabm josamb josmab josmba jsmboa jsmbao jsmoba
jsmoab jsmaob jsmabo jsbmoa jsbmao jsboma jsboam jsbaom jsbamo jsobma jsobam
jsomba jsomab jsoamb jsoabm jsabom jsabmo jsaobm jsaomb jsamob jsambo ajmbos
ajmbso ajmobs ajmosb ajmsob ajmsbo ajbmos ajbmso ajboms ajbosm ajbsom ajbsmo
ajobms ajobsm ajombs ajomsb ajosmb ajosbm ajsbom ajsbmo ajsobm ajsomb ajsmob
ajsmbo amjbos amjbso amjobs amjosb amjsob amjsbo ambjos ambjso ambojs ambosj
ambsoj ambsjo amobjs amobsj amojbs amojsb amosjb amosbj amsboj amsbjo amsobj
amsojb amsjob amsjbo abmjos abmjso abmojs abmosj abmsoj abmsjo abjmos abjmso
abjoms abjosm abjsom abjsmo abojms abojsm abomjs abomsj abosmj abosjm absjom
absjmo absojm absomj absmoj absmjo aombjs aombsj aomjbs aomjsb aomsjb aomsbj
aobmjs aobmsj aobjms aobjsm aobsjm aobsmj aojbms aojbsm aojmbs aojmsb aojsmb
aojsbm aosbjm aosbmj aosjbm aosjmb aosmjb aosmbj asmboj asmbjo asmobj asmojb
asmjob asmjbo asbmoj asbmjo asbomj asbojm asbjom asbjmo asobmj asobjm asombj
asomjb asojmb asojbm asjbom asjbmo asjobm asjomb asjmob asjmbo majbos majbso
majobs majosb majsob majsbo mabjos mabjso mabojs mabosj mabsoj mabsjo maobjs
maobsj maojbs maojsb maosjb maosbj masboj masbjo masobj masojb masjob masjbo
mjabos mjabso mjaobs mjaosb mjasob mjasbo mjbaos mjbaso mjboas mjbosa mjbsoa
mjbsao mjobas mjobsa mjoabs mjoasb mjosab mjosba mjsboa mjsbao mjsoba mjsoab
mjsaob mjsabo mbjaos mbjaso mbjoas mbjosa mbjsoa mbjsao mbajos mbajso mbaojs
mbaosj mbasoj mbasjo mboajs mboasj mbojas mbojsa mbosja mbosaj mbsaoj mbsajo
mbsoaj mbsoja mbsjoa mbsjao mojbas mojbsa mojabs mojasb mojsab mojsba mobjas
mobjsa mobajs mobasj mobsaj mobsja moabjs moabsj moajbs moajsb moasjb moasbj
mosbaj mosbja mosabj mosajb mosjab mosjba msjboa msjbao msjoba msjoab msjaob
msjabo msbjoa msbjao msboja msboaj msbaoj msbajo msobja msobaj msojba msojab
msoajb msoabj msaboj msabjo msaobj msaojb msajob msajbo bamjos bamjso bamojs
bamosj bamsoj bamsjo bajmos bajmso bajoms bajosm bajsom bajsmo baojms baojsm
baomjs baomsj baosmj baosjm basjom basjmo basojm basomj basmoj basmjo bmajos
bmajso bmaojs bmaosj bmasoj bmasjo bmjaos bmjaso bmjoas bmjosa bmjsoa bmjsao
bmojas bmojsa bmoajs bmoasj bmosaj bmosja bmsjoa bmsjao bmsoja bmsoaj bmsaoj
bmsajo bjmaos bjmaso bjmoas bjmosa bjmsoa bjmsao bjamos bjamso bjaoms bjaosm
bjasom bjasmo bjoams bjoasm bjomas bjomsa bjosma bjosam bjsaom bjsamo bjsoam
bjsoma bjsmoa bjsmao bomjas bomjsa bomajs bomasj bomsaj bomsja bojmas bojmsa
bojams bojasm bojsam bojsma boajms boajsm boamjs boamsj boasmj boasjm bosjam
bosjma bosajm bosamj bosmaj bosmja bsmjoa bsmjao bsmoja bsmoaj bsmaoj bsmajo
bsjmoa bsjmao bsjoma bsjoam bsjaom bsjamo bsojma bsojam bsomja bsomaj bsoamj
bsoajm bsajom bsajmo bsaojm bsaomj bsamoj bsamjo oambjs oambsj oamjbs oamjsb
oamsjb oamsbj oabmjs oabmsj oabjms oabjsm oabsjm oabsmj oajbms oajbsm oajmbs
oajmsb oajsmb oajsbm oasbjm oasbmj oasjbm oasjmb oasmjb oasmbj omabjs omabsj
omajbs omajsb omasjb omasbj ombajs ombasj ombjas ombjsa ombsja ombsaj omjbas
omjbsa omjabs omjasb omjsab omjsba omsbja omsbaj omsjba omsjab omsajb omsabj
obmajs obmasj obmjas obmjsa obmsja obmsaj obamjs obamsj obajms obajsm obasjm
obasmj objams objasm objmas objmsa objsma objsam obsajm obsamj obsjam obsjma
obsmja obsmaj ojmbas ojmbsa ojmabs ojmasb ojmsab ojmsba ojbmas ojbmsa ojbams
ojbasm ojbsam ojbsma ojabms ojabsm ojambs ojamsb ojasmb ojasbm ojsbam ojsbma
ojsabm ojsamb ojsmab ojsmba osmbja osmbaj osmjba osmjab osmajb osmabj osbmja
osbmaj osbjma osbjam osbajm osbamj osjbma osjbam osjmba osjmab osjamb osjabm
osabjm osabmj osajbm osajmb osamjb osambj samboj sambjo samobj samojb samjob
samjbo sabmoj sabmjo sabomj sabojm sabjom sabjmo saobmj saobjm saombj saomjb
saojmb saojbm sajbom sajbmo sajobm sajomb sajmob sajmbo smaboj smabjo smaobj
smaojb smajob smajbo smbaoj smbajo smboaj smboja smbjoa smbjao smobaj smobja
smoabj smoajb smojab smojba smjboa smjbao smjoba smjoab smjaob smjabo sbmaoj
sbmajo sbmoaj sbmoja sbmjoa sbmjao sbamoj sbamjo sbaomj sbaojm sbajom sbajmo
sboamj sboajm sbomaj sbomja sbojma sbojam sbjaom sbjamo sbjoam sbjoma sbjmoa
sbjmao sombaj sombja somabj somajb somjab somjba sobmaj sobmja sobamj sobajm
sobjam sobjma soabmj soabjm soambj soamjb soajmb soajbm sojbam sojbma sojabm
sojamb sojmab sojmba sjmboa sjmbao sjmoba sjmoab sjmaob sjmabo sjbmoa sjbmao
sjboma sjboam sjbaom sjbamo sjobma sjobam sjomba sjomab sjoamb sjoabm sjabom
sjabmo sjaobm sjaomb sjamob sjambo

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