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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: pingos
cipher variations:
qjohpt rkpiqu slqjrv tmrksw unsltx
votmuy wpunvz xqvowa yrwpxb zsxqyc
atyrzd buzsae cvatbf dwbucg excvdh
fydwei gzexfj hafygk ibgzhl jchaim
kdibjn lejcko mfkdlp nglemq ohmfnr

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: pingos
Cipher: krmtlh

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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: pingos

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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: pingos
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: pingos
Cipher: cvatbf

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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: pingos
Cipher: 534233224334

Extended Methods:
Method #1

Plaintext: pingos
method variations:

Method #2
Bifid cipher
The message is converted to its coordinates in the usual manner, but they are written vertically beneath:
p i n g o s 
5 4 3 2 4 3 
3 2 3 2 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: pingos
Cipher: uhohhs

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Method #3

Plaintext: pingos
method variations:
smhrny mhrnys hrnysm
rnysmh nysmhr ysmhrn

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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: pingos

all 720 cipher variations:
pingos pingso pinogs pinosg pinsog pinsgo pignos pignso pigons pigosn pigson
pigsno piogns piogsn piongs pionsg piosng piosgn pisgon pisgno pisogn pisong
pisnog pisngo pnigos pnigso pniogs pniosg pnisog pnisgo pngios pngiso pngois
pngosi pngsoi pngsio pnogis pnogsi pnoigs pnoisg pnosig pnosgi pnsgoi pnsgio
pnsogi pnsoig pnsiog pnsigo pgnios pgniso pgnois pgnosi pgnsoi pgnsio pginos
pginso pgions pgiosn pgison pgisno pgoins pgoisn pgonis pgonsi pgosni pgosin
pgsion pgsino pgsoin pgsoni pgsnoi pgsnio pongis pongsi ponigs ponisg ponsig
ponsgi pognis pognsi pogins pogisn pogsin pogsni poigns poigsn poings poinsg
poisng poisgn posgin posgni posign posing posnig posngi psngoi psngio psnogi
psnoig psniog psnigo psgnoi psgnio psgoni psgoin psgion psgino psogni psogin
psongi psonig psoing psoign psigon psigno psiogn psiong psinog psingo ipngos
ipngso ipnogs ipnosg ipnsog ipnsgo ipgnos ipgnso ipgons ipgosn ipgson ipgsno
ipogns ipogsn ipongs iponsg iposng iposgn ipsgon ipsgno ipsogn ipsong ipsnog
ipsngo inpgos inpgso inpogs inposg inpsog inpsgo ingpos ingpso ingops ingosp
ingsop ingspo inogps inogsp inopgs inopsg inospg inosgp insgop insgpo insogp
insopg inspog inspgo ignpos ignpso ignops ignosp ignsop ignspo igpnos igpnso
igpons igposn igpson igpsno igopns igopsn igonps igonsp igosnp igospn igspon
igspno igsopn igsonp igsnop igsnpo iongps iongsp ionpgs ionpsg ionspg ionsgp
iognps iognsp iogpns iogpsn iogspn iogsnp iopgns iopgsn iopngs iopnsg iopsng
iopsgn iosgpn iosgnp iospgn iospng iosnpg iosngp isngop isngpo isnogp isnopg
isnpog isnpgo isgnop isgnpo isgonp isgopn isgpon isgpno isognp isogpn isongp
isonpg isopng isopgn ispgon ispgno ispogn ispong ispnog ispngo nipgos nipgso
nipogs niposg nipsog nipsgo nigpos nigpso nigops nigosp nigsop nigspo niogps
niogsp niopgs niopsg niospg niosgp nisgop nisgpo nisogp nisopg nispog nispgo
npigos npigso npiogs npiosg npisog npisgo npgios npgiso npgois npgosi npgsoi
npgsio npogis npogsi npoigs npoisg nposig nposgi npsgoi npsgio npsogi npsoig
npsiog npsigo ngpios ngpiso ngpois ngposi ngpsoi ngpsio ngipos ngipso ngiops
ngiosp ngisop ngispo ngoips ngoisp ngopis ngopsi ngospi ngosip ngsiop ngsipo
ngsoip ngsopi ngspoi ngspio nopgis nopgsi nopigs nopisg nopsig nopsgi nogpis
nogpsi nogips nogisp nogsip nogspi noigps noigsp noipgs noipsg noispg noisgp
nosgip nosgpi nosigp nosipg nospig nospgi nspgoi nspgio nspogi nspoig nspiog
nspigo nsgpoi nsgpio nsgopi nsgoip nsgiop nsgipo nsogpi nsogip nsopgi nsopig
nsoipg nsoigp nsigop nsigpo nsiogp nsiopg nsipog nsipgo ginpos ginpso ginops
ginosp ginsop ginspo gipnos gipnso gipons giposn gipson gipsno giopns giopsn
gionps gionsp giosnp giospn gispon gispno gisopn gisonp gisnop gisnpo gnipos
gnipso gniops gniosp gnisop gnispo gnpios gnpiso gnpois gnposi gnpsoi gnpsio
gnopis gnopsi gnoips gnoisp gnosip gnospi gnspoi gnspio gnsopi gnsoip gnsiop
gnsipo gpnios gpniso gpnois gpnosi gpnsoi gpnsio gpinos gpinso gpions gpiosn
gpison gpisno gpoins gpoisn gponis gponsi gposni gposin gpsion gpsino gpsoin
gpsoni gpsnoi gpsnio gonpis gonpsi gonips gonisp gonsip gonspi gopnis gopnsi
gopins gopisn gopsin gopsni goipns goipsn goinps goinsp goisnp goispn gospin
gospni gosipn gosinp gosnip gosnpi gsnpoi gsnpio gsnopi gsnoip gsniop gsnipo
gspnoi gspnio gsponi gspoin gspion gspino gsopni gsopin gsonpi gsonip gsoinp
gsoipn gsipon gsipno gsiopn gsionp gsinop gsinpo oingps oingsp oinpgs oinpsg
oinspg oinsgp oignps oignsp oigpns oigpsn oigspn oigsnp oipgns oipgsn oipngs
oipnsg oipsng oipsgn oisgpn oisgnp oispgn oispng oisnpg oisngp onigps onigsp
onipgs onipsg onispg onisgp ongips ongisp ongpis ongpsi ongspi ongsip onpgis
onpgsi onpigs onpisg onpsig onpsgi onsgpi onsgip onspgi onspig onsipg onsigp
ognips ognisp ognpis ognpsi ognspi ognsip oginps oginsp ogipns ogipsn ogispn
ogisnp ogpins ogpisn ogpnis ogpnsi ogpsni ogpsin ogsipn ogsinp ogspin ogspni
ogsnpi ogsnip opngis opngsi opnigs opnisg opnsig opnsgi opgnis opgnsi opgins
opgisn opgsin opgsni opigns opigsn opings opinsg opisng opisgn opsgin opsgni
opsign opsing opsnig opsngi osngpi osngip osnpgi osnpig osnipg osnigp osgnpi
osgnip osgpni osgpin osgipn osginp ospgni ospgin ospngi ospnig osping ospign
osigpn osignp osipgn osipng osinpg osingp singop singpo sinogp sinopg sinpog
sinpgo signop signpo sigonp sigopn sigpon sigpno siognp siogpn siongp sionpg
siopng siopgn sipgon sipgno sipogn sipong sipnog sipngo snigop snigpo sniogp
sniopg snipog snipgo sngiop sngipo sngoip sngopi sngpoi sngpio snogip snogpi
snoigp snoipg snopig snopgi snpgoi snpgio snpogi snpoig snpiog snpigo sgniop
sgnipo sgnoip sgnopi sgnpoi sgnpio sginop sginpo sgionp sgiopn sgipon sgipno
sgoinp sgoipn sgonip sgonpi sgopni sgopin sgpion sgpino sgpoin sgponi sgpnoi
sgpnio songip songpi sonigp sonipg sonpig sonpgi sognip sognpi soginp sogipn
sogpin sogpni soignp soigpn soingp soinpg soipng soipgn sopgin sopgni sopign
soping sopnig sopngi spngoi spngio spnogi spnoig spniog spnigo spgnoi spgnio
spgoni spgoin spgion spgino spogni spogin spongi sponig spoing spoign spigon
spigno spiogn spiong spinog spingo

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