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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: rosana
cipher variations:
sptbob tqucpc urvdqd vswere wtxfsf
xuygtg yvzhuh zwaivi axbjwj byckxk
czdlyl daemzm ebfnan fcgobo gdhpcp
heiqdq ifjrer jgksfs khltgt limuhu
mjnviv nkowjw olpxkx pmqyly qnrzmz

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: rosana
Cipher: ilhzmz

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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: rosana

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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: rosana
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: rosana
Cipher: ebfnan

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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: rosana
Cipher: 244334113311

Extended Methods:
Method #1

Plaintext: rosana
method variations:

Method #2
Bifid cipher
The message is converted to its coordinates in the usual manner, but they are written vertically beneath:
r o s a n a 
2 4 3 1 3 1 
4 3 4 1 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: rosana
Cipher: rccodc

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Method #3

Plaintext: rosana
method variations:
tndlcf ndlcft dlcftn
lcftnd cftndl ftndlc

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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: rosana

all 720 cipher variations:
rosana rosaan rosnaa rosnaa rosana rosaan roasna roasan roansa roanas roaans
roaasn ronasa ronaas ronsaa ronsaa ronasa ronaas roaans roaasn roanas roansa
roasna roasan rsoana rsoaan rsonaa rsonaa rsoana rsoaan rsaona rsaoan rsanoa
rsanao rsaano rsaaon rsnaoa rsnaao rsnoaa rsnoaa rsnaoa rsnaao rsaano rsaaon
rsanao rsanoa rsaona rsaoan rasona rasoan rasnoa rasnao rasano rasaon raosna
raosan raonsa raonas raoans raoasn ranosa ranoas ransoa ransao ranaso ranaos
raaons raaosn raanos raanso raasno raason rnsaoa rnsaao rnsoaa rnsoaa rnsaoa
rnsaao rnasoa rnasao rnaosa rnaoas rnaaos rnaaso rnoasa rnoaas rnosaa rnosaa
rnoasa rnoaas rnaaos rnaaso rnaoas rnaosa rnasoa rnasao rasano rasaon rasnao
rasnoa rasona rasoan raasno raason raanso raanos raaons raaosn ranaso ranaos
ransao ransoa ranosa ranoas raoans raoasn raonas raonsa raosna raosan orsana
orsaan orsnaa orsnaa orsana orsaan orasna orasan oransa oranas oraans oraasn
ornasa ornaas ornsaa ornsaa ornasa ornaas oraans oraasn oranas oransa orasna
orasan osrana osraan osrnaa osrnaa osrana osraan osarna osaran osanra osanar
osaanr osaarn osnara osnaar osnraa osnraa osnara osnaar osaanr osaarn osanar
osanra osarna osaran oasrna oasran oasnra oasnar oasanr oasarn oarsna oarsan
oarnsa oarnas oarans oarasn oanrsa oanras oansra oansar oanasr oanars oaarns
oaarsn oaanrs oaansr oaasnr oaasrn onsara onsaar onsraa onsraa onsara onsaar
onasra onasar onarsa onaras onaars onaasr onrasa onraas onrsaa onrsaa onrasa
onraas onaars onaasr onaras onarsa onasra onasar oasanr oasarn oasnar oasnra
oasrna oasran oaasnr oaasrn oaansr oaanrs oaarns oaarsn oanasr oanars oansar
oansra oanrsa oanras oarans oarasn oarnas oarnsa oarsna oarsan sorana soraan
sornaa sornaa sorana soraan soarna soaran soanra soanar soaanr soaarn sonara
sonaar sonraa sonraa sonara sonaar soaanr soaarn soanar soanra soarna soaran
sroana sroaan sronaa sronaa sroana sroaan sraona sraoan sranoa sranao sraano
sraaon srnaoa srnaao srnoaa srnoaa srnaoa srnaao sraano sraaon sranao sranoa
sraona sraoan sarona saroan sarnoa sarnao sarano saraon saorna saoran saonra
saonar saoanr saoarn sanora sanoar sanroa sanrao sanaro sanaor saaonr saaorn
saanor saanro saarno saaron snraoa snraao snroaa snroaa snraoa snraao snaroa
snarao snaora snaoar snaaor snaaro snoara snoaar snoraa snoraa snoara snoaar
snaaor snaaro snaoar snaora snaroa snarao sarano saraon sarnao sarnoa sarona
saroan saarno saaron saanro saanor saaonr saaorn sanaro sanaor sanrao sanroa
sanora sanoar saoanr saoarn saonar saonra saorna saoran aosrna aosran aosnra
aosnar aosanr aosarn aorsna aorsan aornsa aornas aorans aorasn aonrsa aonras
aonsra aonsar aonasr aonars aoarns aoarsn aoanrs aoansr aoasnr aoasrn asorna
asoran asonra asonar asoanr asoarn asrona asroan asrnoa asrnao asrano asraon
asnroa asnrao asnora asnoar asnaor asnaro asarno asaron asanro asanor asaonr
asaorn arsona arsoan arsnoa arsnao arsano arsaon arosna arosan aronsa aronas
aroans aroasn arnosa arnoas arnsoa arnsao arnaso arnaos araons araosn aranos
aranso arasno arason ansroa ansrao ansora ansoar ansaor ansaro anrsoa anrsao
anrosa anroas anraos anraso anorsa anoras anosra anosar anoasr anoars anaros
anarso anaors anaosr anasor anasro aasrno aasron aasnro aasnor aasonr aasorn
aarsno aarson aarnso aarnos aarons aarosn aanrso aanros aansro aansor aanosr
aanors aaorns aaorsn aaonrs aaonsr aaosnr aaosrn nosara nosaar nosraa nosraa
nosara nosaar noasra noasar noarsa noaras noaars noaasr norasa noraas norsaa
norsaa norasa noraas noaars noaasr noaras noarsa noasra noasar nsoara nsoaar
nsoraa nsoraa nsoara nsoaar nsaora nsaoar nsaroa nsarao nsaaro nsaaor nsraoa
nsraao nsroaa nsroaa nsraoa nsraao nsaaro nsaaor nsarao nsaroa nsaora nsaoar
nasora nasoar nasroa nasrao nasaro nasaor naosra naosar naorsa naoras naoars
naoasr narosa naroas narsoa narsao naraso naraos naaors naaosr naaros naarso
naasro naasor nrsaoa nrsaao nrsoaa nrsoaa nrsaoa nrsaao nrasoa nrasao nraosa
nraoas nraaos nraaso nroasa nroaas nrosaa nrosaa nroasa nroaas nraaos nraaso
nraoas nraosa nrasoa nrasao nasaro nasaor nasrao nasroa nasora nasoar naasro
naasor naarso naaros naaors naaosr naraso naraos narsao narsoa narosa naroas
naoars naoasr naoras naorsa naosra naosar aosanr aosarn aosnar aosnra aosrna
aosran aoasnr aoasrn aoansr aoanrs aoarns aoarsn aonasr aonars aonsar aonsra
aonrsa aonras aorans aorasn aornas aornsa aorsna aorsan asoanr asoarn asonar
asonra asorna asoran asaonr asaorn asanor asanro asarno asaron asnaor asnaro
asnoar asnora asnroa asnrao asrano asraon asrnao asrnoa asrona asroan aasonr
aasorn aasnor aasnro aasrno aasron aaosnr aaosrn aaonsr aaonrs aaorns aaorsn
aanosr aanors aansor aansro aanrso aanros aarons aarosn aarnos aarnso aarsno
aarson ansaor ansaro ansoar ansora ansroa ansrao anasor anasro anaosr anaors
anaros anarso anoasr anoars anosar anosra anorsa anoras anraos anraso anroas
anrosa anrsoa anrsao arsano arsaon arsnao arsnoa arsona arsoan arasno arason
aranso aranos araons araosn arnaso arnaos arnsao arnsoa arnosa arnoas aroans
aroasn aronas aronsa arosna arosan

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History of cryptography
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