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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: prance
cipher variations:
qsbodf rtcpeg sudqfh tvergi uwfshj
vxgtik wyhujl xzivkm yajwln zbkxmo
aclynp bdmzoq cenapr dfobqs egpcrt
fhqdsu giretv hjsfuw iktgvx jluhwy
kmvixz lnwjya moxkzb npylac oqzmbd

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: prance
Cipher: kizmxv

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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: prance

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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: prance
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: prance
Cipher: cenapr

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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: prance
Cipher: 532411333151

Extended Methods:
Method #1

Plaintext: prance
method variations:

Method #2
Bifid cipher
The message is converted to its coordinates in the usual manner, but they are written vertically beneath:
p r a n c e 
5 2 1 3 3 5 
3 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: prance
Cipher: klxsla

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Method #3

Plaintext: prance
method variations:
hdlnvv dlnvvh lnvvhd
nvvhdl vvhdln vhdlnv

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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: prance

all 720 cipher variations:
prance pranec pracne pracen praecn praenc prnace prnaec prncae prncea prneca
prneac prcnae prcnea prcane prcaen prcean prcena prenca prenac precna precan
preacn preanc parnce parnec parcne parcen parecn parenc panrce panrec pancre
pancer panecr panerc pacnre pacner pacrne pacren pacern pacenr paencr paenrc
paecnr paecrn paercn paernc pnarce pnarec pnacre pnacer pnaecr pnaerc pnrace
pnraec pnrcae pnrcea pnreca pnreac pncrae pncrea pncare pncaer pncear pncera
pnerca pnerac pnecra pnecar pneacr pnearc pcanre pcaner pcarne pcaren pcaern
pcaenr pcnare pcnaer pcnrae pcnrea pcnera pcnear pcrnae pcrnea pcrane pcraen
pcrean pcrena pcenra pcenar pcerna pceran pcearn pceanr peancr peanrc peacnr
peacrn pearcn pearnc penacr penarc pencar pencra penrca penrac pecnar pecnra
pecanr pecarn pecran pecrna pernca pernac percna percan peracn peranc rpance
rpanec rpacne rpacen rpaecn rpaenc rpnace rpnaec rpncae rpncea rpneca rpneac
rpcnae rpcnea rpcane rpcaen rpcean rpcena rpenca rpenac rpecna rpecan rpeacn
rpeanc rapnce rapnec rapcne rapcen rapecn rapenc ranpce ranpec rancpe rancep
ranecp ranepc racnpe racnep racpne racpen racepn racenp raencp raenpc raecnp
raecpn raepcn raepnc rnapce rnapec rnacpe rnacep rnaecp rnaepc rnpace rnpaec
rnpcae rnpcea rnpeca rnpeac rncpae rncpea rncape rncaep rnceap rncepa rnepca
rnepac rnecpa rnecap rneacp rneapc rcanpe rcanep rcapne rcapen rcaepn rcaenp
rcnape rcnaep rcnpae rcnpea rcnepa rcneap rcpnae rcpnea rcpane rcpaen rcpean
rcpena rcenpa rcenap rcepna rcepan rceapn rceanp reancp reanpc reacnp reacpn
reapcn reapnc renacp renapc rencap rencpa renpca renpac recnap recnpa recanp
recapn recpan recpna repnca repnac repcna repcan repacn repanc arpnce arpnec
arpcne arpcen arpecn arpenc arnpce arnpec arncpe arncep arnecp arnepc arcnpe
arcnep arcpne arcpen arcepn arcenp arencp arenpc arecnp arecpn arepcn arepnc
aprnce aprnec aprcne aprcen aprecn aprenc apnrce apnrec apncre apncer apnecr
apnerc apcnre apcner apcrne apcren apcern apcenr apencr apenrc apecnr apecrn
apercn apernc anprce anprec anpcre anpcer anpecr anperc anrpce anrpec anrcpe
anrcep anrecp anrepc ancrpe ancrep ancpre ancper ancepr ancerp anercp anerpc
anecrp anecpr anepcr aneprc acpnre acpner acprne acpren acpern acpenr acnpre
acnper acnrpe acnrep acnerp acnepr acrnpe acrnep acrpne acrpen acrepn acrenp
acenrp acenpr acernp acerpn aceprn acepnr aepncr aepnrc aepcnr aepcrn aeprcn
aeprnc aenpcr aenprc aencpr aencrp aenrcp aenrpc aecnpr aecnrp aecpnr aecprn
aecrpn aecrnp aerncp aernpc aercnp aercpn aerpcn aerpnc nrapce nrapec nracpe
nracep nraecp nraepc nrpace nrpaec nrpcae nrpcea nrpeca nrpeac nrcpae nrcpea
nrcape nrcaep nrceap nrcepa nrepca nrepac nrecpa nrecap nreacp nreapc narpce
narpec narcpe narcep narecp narepc naprce naprec napcre napcer napecr naperc
nacpre nacper nacrpe nacrep nacerp nacepr naepcr naeprc naecpr naecrp naercp
naerpc nparce nparec npacre npacer npaecr npaerc nprace npraec nprcae nprcea
npreca npreac npcrae npcrea npcare npcaer npcear npcera nperca nperac npecra
npecar npeacr npearc ncapre ncaper ncarpe ncarep ncaerp ncaepr ncpare ncpaer
ncprae ncprea ncpera ncpear ncrpae ncrpea ncrape ncraep ncreap ncrepa ncepra
ncepar ncerpa ncerap ncearp nceapr neapcr neaprc neacpr neacrp nearcp nearpc
nepacr neparc nepcar nepcra neprca neprac necpar necpra necapr necarp necrap
necrpa nerpca nerpac nercpa nercap neracp nerapc cranpe cranep crapne crapen
craepn craenp crnape crnaep crnpae crnpea crnepa crneap crpnae crpnea crpane
crpaen crpean crpena crenpa crenap crepna crepan creapn creanp carnpe carnep
carpne carpen carepn carenp canrpe canrep canpre canper canepr canerp capnre
capner caprne capren capern capenr caenpr caenrp caepnr caeprn caerpn caernp
cnarpe cnarep cnapre cnaper cnaepr cnaerp cnrape cnraep cnrpae cnrpea cnrepa
cnreap cnprae cnprea cnpare cnpaer cnpear cnpera cnerpa cnerap cnepra cnepar
cneapr cnearp cpanre cpaner cparne cparen cpaern cpaenr cpnare cpnaer cpnrae
cpnrea cpnera cpnear cprnae cprnea cprane cpraen cprean cprena cpenra cpenar
cperna cperan cpearn cpeanr ceanpr ceanrp ceapnr ceaprn cearpn cearnp cenapr
cenarp cenpar cenpra cenrpa cenrap cepnar cepnra cepanr ceparn cepran ceprna
cernpa cernap cerpna cerpan cerapn ceranp erancp eranpc eracnp eracpn erapcn
erapnc ernacp ernapc erncap erncpa ernpca ernpac ercnap ercnpa ercanp ercapn
ercpan ercpna erpnca erpnac erpcna erpcan erpacn erpanc earncp earnpc earcnp
earcpn earpcn earpnc eanrcp eanrpc eancrp eancpr eanpcr eanprc eacnrp eacnpr
eacrnp eacrpn eacprn eacpnr eapncr eapnrc eapcnr eapcrn eaprcn eaprnc enarcp
enarpc enacrp enacpr enapcr enaprc enracp enrapc enrcap enrcpa enrpca enrpac
encrap encrpa encarp encapr encpar encpra enprca enprac enpcra enpcar enpacr
enparc ecanrp ecanpr ecarnp ecarpn ecaprn ecapnr ecnarp ecnapr ecnrap ecnrpa
ecnpra ecnpar ecrnap ecrnpa ecranp ecrapn ecrpan ecrpna ecpnra ecpnar ecprna
ecpran ecparn ecpanr epancr epanrc epacnr epacrn eparcn eparnc epnacr epnarc
epncar epncra epnrca epnrac epcnar epcnra epcanr epcarn epcran epcrna eprnca
eprnac eprcna eprcan epracn epranc

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