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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: framed
cipher variations:
gsbnfe htcogf iudphg jveqih kwfrji
lxgskj myhtlk nziuml oajvnm pbkwon
qclxpo rdmyqp senzrq tfoasr ugpbts
vhqcut wirdvu xjsewv yktfxw zlugyx
amvhzy bnwiaz coxjba dpykcb eqzldc

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: framed
Cipher: uiznvw

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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: framed

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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: framed
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: framed
Cipher: senzrq

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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: framed
Cipher: 122411235141

Extended Methods:
Method #1

Plaintext: framed
method variations:

Method #2
Bifid cipher
The message is converted to its coordinates in the usual manner, but they are written vertically beneath:
f r a m e d 
1 2 1 2 5 4 
2 4 1 3 1 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: framed
Cipher: ffurla

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Method #3

Plaintext: framed
method variations:
gdfxqa dfxqag fxqagd
xqagdf qagdfx agdfxq

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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: framed

all 720 cipher variations:
framed framde fraemd fraedm fradem fradme frmaed frmade frmead frmeda frmdea
frmdae fremad fremda freamd freadm fredam fredma frdmea frdmae frdema frdeam
frdaem frdame farmed farmde faremd faredm fardem fardme famred famrde famerd
famedr famder famdre faemrd faemdr faermd faerdm faedrm faedmr fadmer fadmre
fademr faderm fadrem fadrme fmared fmarde fmaerd fmaedr fmader fmadre fmraed
fmrade fmread fmreda fmrdea fmrdae fmerad fmerda fmeard fmeadr fmedar fmedra
fmdrea fmdrae fmdera fmdear fmdaer fmdare feamrd feamdr fearmd feardm feadrm
feadmr femard femadr femrad femrda femdra femdar fermad fermda feramd feradm
ferdam ferdma fedmra fedmar fedrma fedram fedarm fedamr fdamer fdamre fdaemr
fdaerm fdarem fdarme fdmaer fdmare fdmear fdmera fdmrea fdmrae fdemar fdemra
fdeamr fdearm fderam fderma fdrmea fdrmae fdrema fdream fdraem fdrame rfamed
rfamde rfaemd rfaedm rfadem rfadme rfmaed rfmade rfmead rfmeda rfmdea rfmdae
rfemad rfemda rfeamd rfeadm rfedam rfedma rfdmea rfdmae rfdema rfdeam rfdaem
rfdame rafmed rafmde rafemd rafedm rafdem rafdme ramfed ramfde ramefd ramedf
ramdef ramdfe raemfd raemdf raefmd raefdm raedfm raedmf radmef radmfe rademf
radefm radfem radfme rmafed rmafde rmaefd rmaedf rmadef rmadfe rmfaed rmfade
rmfead rmfeda rmfdea rmfdae rmefad rmefda rmeafd rmeadf rmedaf rmedfa rmdfea
rmdfae rmdefa rmdeaf rmdaef rmdafe reamfd reamdf reafmd reafdm readfm readmf
remafd remadf remfad remfda remdfa remdaf refmad refmda refamd refadm refdam
refdma redmfa redmaf redfma redfam redafm redamf rdamef rdamfe rdaemf rdaefm
rdafem rdafme rdmaef rdmafe rdmeaf rdmefa rdmfea rdmfae rdemaf rdemfa rdeamf
rdeafm rdefam rdefma rdfmea rdfmae rdfema rdfeam rdfaem rdfame arfmed arfmde
arfemd arfedm arfdem arfdme armfed armfde armefd armedf armdef armdfe aremfd
aremdf arefmd arefdm aredfm aredmf ardmef ardmfe ardemf ardefm ardfem ardfme
afrmed afrmde afremd afredm afrdem afrdme afmred afmrde afmerd afmedr afmder
afmdre afemrd afemdr afermd aferdm afedrm afedmr afdmer afdmre afdemr afderm
afdrem afdrme amfred amfrde amferd amfedr amfder amfdre amrfed amrfde amrefd
amredf amrdef amrdfe amerfd amerdf amefrd amefdr amedfr amedrf amdref amdrfe
amderf amdefr amdfer amdfre aefmrd aefmdr aefrmd aefrdm aefdrm aefdmr aemfrd
aemfdr aemrfd aemrdf aemdrf aemdfr aermfd aermdf aerfmd aerfdm aerdfm aerdmf
aedmrf aedmfr aedrmf aedrfm aedfrm aedfmr adfmer adfmre adfemr adferm adfrem
adfrme admfer admfre admefr admerf admref admrfe ademfr ademrf adefmr adefrm
aderfm adermf adrmef adrmfe adremf adrefm adrfem adrfme mrafed mrafde mraefd
mraedf mradef mradfe mrfaed mrfade mrfead mrfeda mrfdea mrfdae mrefad mrefda
mreafd mreadf mredaf mredfa mrdfea mrdfae mrdefa mrdeaf mrdaef mrdafe marfed
marfde marefd maredf mardef mardfe mafred mafrde maferd mafedr mafder mafdre
maefrd maefdr maerfd maerdf maedrf maedfr madfer madfre madefr maderf madref
madrfe mfared mfarde mfaerd mfaedr mfader mfadre mfraed mfrade mfread mfreda
mfrdea mfrdae mferad mferda mfeard mfeadr mfedar mfedra mfdrea mfdrae mfdera
mfdear mfdaer mfdare meafrd meafdr mearfd meardf meadrf meadfr mefard mefadr
mefrad mefrda mefdra mefdar merfad merfda merafd meradf merdaf merdfa medfra
medfar medrfa medraf medarf medafr mdafer mdafre mdaefr mdaerf mdaref mdarfe
mdfaer mdfare mdfear mdfera mdfrea mdfrae mdefar mdefra mdeafr mdearf mderaf
mderfa mdrfea mdrfae mdrefa mdreaf mdraef mdrafe eramfd eramdf erafmd erafdm
eradfm eradmf ermafd ermadf ermfad ermfda ermdfa ermdaf erfmad erfmda erfamd
erfadm erfdam erfdma erdmfa erdmaf erdfma erdfam erdafm erdamf earmfd earmdf
earfmd earfdm eardfm eardmf eamrfd eamrdf eamfrd eamfdr eamdfr eamdrf eafmrd
eafmdr eafrmd eafrdm eafdrm eafdmr eadmfr eadmrf eadfmr eadfrm eadrfm eadrmf
emarfd emardf emafrd emafdr emadfr emadrf emrafd emradf emrfad emrfda emrdfa
emrdaf emfrad emfrda emfard emfadr emfdar emfdra emdrfa emdraf emdfra emdfar
emdafr emdarf efamrd efamdr efarmd efardm efadrm efadmr efmard efmadr efmrad
efmrda efmdra efmdar efrmad efrmda eframd efradm efrdam efrdma efdmra efdmar
efdrma efdram efdarm efdamr edamfr edamrf edafmr edafrm edarfm edarmf edmafr
edmarf edmfar edmfra edmrfa edmraf edfmar edfmra edfamr edfarm edfram edfrma
edrmfa edrmaf edrfma edrfam edrafm edramf dramef dramfe draemf draefm drafem
drafme drmaef drmafe drmeaf drmefa drmfea drmfae dremaf dremfa dreamf dreafm
drefam drefma drfmea drfmae drfema drfeam drfaem drfame darmef darmfe daremf
darefm darfem darfme damref damrfe damerf damefr damfer damfre daemrf daemfr
daermf daerfm daefrm daefmr dafmer dafmre dafemr daferm dafrem dafrme dmaref
dmarfe dmaerf dmaefr dmafer dmafre dmraef dmrafe dmreaf dmrefa dmrfea dmrfae
dmeraf dmerfa dmearf dmeafr dmefar dmefra dmfrea dmfrae dmfera dmfear dmfaer
dmfare deamrf deamfr dearmf dearfm deafrm deafmr demarf demafr demraf demrfa
demfra demfar dermaf dermfa deramf derafm derfam derfma defmra defmar defrma
defram defarm defamr dfamer dfamre dfaemr dfaerm dfarem dfarme dfmaer dfmare
dfmear dfmera dfmrea dfmrae dfemar dfemra dfeamr dfearm dferam dferma dfrmea
dfrmae dfrema dfream dfraem dframe

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