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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: nadeem
cipher variations:
obeffn pcfggo qdghhp rehiiq sfijjr
tgjkks uhkllt vilmmu wjmnnv xknoow
yloppx zmpqqy anqrrz borssa cpsttb
dqtuuc eruvvd fsvwwe gtwxxf huxyyg
ivyzzh jwzaai kxabbj lybcck mzcddl

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: nadeem
Cipher: mzwvvn

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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: nadeem

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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: nadeem
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: nadeem
Cipher: anqrrz

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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: nadeem
Cipher: 331141515123

Extended Methods:
Method #1

Plaintext: nadeem
method variations:

Method #2
Bifid cipher
The message is converted to its coordinates in the usual manner, but they are written vertically beneath:
n a d e e m 
3 1 4 5 5 2 
3 1 1 1 1 3 
They are then read out in rows:
Then divided up into pairs again, and the pairs turned back into letters using the square:
Plain: nadeem
Cipher: cykcal

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Method #3

Plaintext: nadeem
method variations:
cqvvfn qvvfnc vvfncq
vfncqv fncqvv ncqvvf

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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: nadeem

all 720 cipher variations:
nadeem nademe nadeem nademe nadmee nadmee naedem naedme naeedm naeemd naemed
naemde naeedm naeemd naedem naedme naemde naemed nameed namede nameed namede
namdee namdee ndaeem ndaeme ndaeem ndaeme ndamee ndamee ndeaem ndeame ndeeam
ndeema ndemea ndemae ndeeam ndeema ndeaem ndeame ndemae ndemea ndmeea ndmeae
ndmeea ndmeae ndmaee ndmaee nedaem nedame nedeam nedema nedmea nedmae neadem
neadme neaedm neaemd neamed neamde neeadm neeamd needam needma neemda neemad
nemaed nemade nemead nemeda nemdea nemdae nedeam nedema nedaem nedame nedmae
nedmea needam needma neeadm neeamd neemad neemda neaedm neaemd neadem neadme
neamde neamed nemead nemeda nemaed nemade nemdae nemdea nmdeea nmdeae nmdeea
nmdeae nmdaee nmdaee nmedea nmedae nmeeda nmeead nmeaed nmeade nmeeda nmeead
nmedea nmedae nmeade nmeaed nmaeed nmaede nmaeed nmaede nmadee nmadee andeem
andeme andeem andeme andmee andmee anedem anedme aneedm aneemd anemed anemde
aneedm aneemd anedem anedme anemde anemed anmeed anmede anmeed anmede anmdee
anmdee adneem adneme adneem adneme adnmee adnmee adenem adenme adeenm adeemn
ademen ademne adeenm adeemn adenem adenme ademne ademen admeen admene admeen
admene admnee admnee aednem aednme aedenm aedemn aedmen aedmne aendem aendme
aenedm aenemd aenmed aenmde aeendm aeenmd aeednm aeedmn aeemdn aeemnd aemned
aemnde aemend aemedn aemden aemdne aedenm aedemn aednem aednme aedmne aedmen
aeednm aeedmn aeendm aeenmd aeemnd aeemdn aenedm aenemd aendem aendme aenmde
aenmed aemend aemedn aemned aemnde aemdne aemden amdeen amdene amdeen amdene
amdnee amdnee ameden amedne ameedn ameend amened amende ameedn ameend ameden
amedne amende amened amneed amnede amneed amnede amndee amndee daneem daneme
daneem daneme danmee danmee daenem daenme daeenm daeemn daemen daemne daeenm
daeemn daenem daenme daemne daemen dameen damene dameen damene damnee damnee
dnaeem dnaeme dnaeem dnaeme dnamee dnamee dneaem dneame dneeam dneema dnemea
dnemae dneeam dneema dneaem dneame dnemae dnemea dnmeea dnmeae dnmeea dnmeae
dnmaee dnmaee denaem dename deneam denema denmea denmae deanem deanme deaenm
deaemn deamen deamne deeanm deeamn deenam deenma deemna deeman demaen demane
demean demena demnea demnae deneam denema denaem dename denmae denmea deenam
deenma deeanm deeamn deeman deemna deaenm deaemn deanem deanme deamne deamen
demean demena demaen demane demnae demnea dmneea dmneae dmneea dmneae dmnaee
dmnaee dmenea dmenae dmeena dmeean dmeaen dmeane dmeena dmeean dmenea dmenae
dmeane dmeaen dmaeen dmaene dmaeen dmaene dmanee dmanee eadnem eadnme eadenm
eademn eadmen eadmne eandem eandme eanedm eanemd eanmed eanmde eaendm eaenmd
eaednm eaedmn eaemdn eaemnd eamned eamnde eamend eamedn eamden eamdne edanem
edanme edaenm edaemn edamen edamne ednaem edname edneam ednema ednmea ednmae
edenam edenma edeanm edeamn edeman edemna edmnea edmnae edmena edmean edmaen
edmane endaem endame endeam endema endmea endmae enadem enadme enaedm enaemd
enamed enamde eneadm eneamd enedam enedma enemda enemad enmaed enmade enmead
enmeda enmdea enmdae eednam eednma eedanm eedamn eedman eedmna eendam eendma
eenadm eenamd eenmad eenmda eeandm eeanmd eeadnm eeadmn eeamdn eeamnd eemnad
eemnda eemand eemadn eemdan eemdna emdnea emdnae emdena emdean emdaen emdane
emndea emndae emneda emnead emnaed emnade emenda emenad emedna emedan emeadn
emeand emaned emande emaend emaedn emaden emadne eadenm eademn eadnem eadnme
eadmne eadmen eaednm eaedmn eaendm eaenmd eaemnd eaemdn eanedm eanemd eandem
eandme eanmde eanmed eamend eamedn eamned eamnde eamdne eamden edaenm edaemn
edanem edanme edamne edamen edeanm edeamn edenam edenma edemna edeman edneam
ednema ednaem edname ednmae ednmea edmena edmean edmnea edmnae edmane edmaen
eedanm eedamn eednam eednma eedmna eedman eeadnm eeadmn eeandm eeanmd eeamnd
eeamdn eenadm eenamd eendam eendma eenmda eenmad eemand eemadn eemnad eemnda
eemdna eemdan endeam endema endaem endame endmae endmea enedam enedma eneadm
eneamd enemad enemda enaedm enaemd enadem enadme enamde enamed enmead enmeda
enmaed enmade enmdae enmdea emdena emdean emdnea emdnae emdane emdaen emedna
emedan emenda emenad emeand emeadn emneda emnead emndea emndae emnade emnaed
emaend emaedn emaned emande emadne emaden madeen madene madeen madene madnee
madnee maeden maedne maeedn maeend maened maende maeedn maeend maeden maedne
maende maened maneed manede maneed manede mandee mandee mdaeen mdaene mdaeen
mdaene mdanee mdanee mdeaen mdeane mdeean mdeena mdenea mdenae mdeean mdeena
mdeaen mdeane mdenae mdenea mdneea mdneae mdneea mdneae mdnaee mdnaee medaen
medane medean medena mednea mednae meaden meadne meaedn meaend meaned meande
meeadn meeand meedan meedna meenda meenad menaed menade menead meneda mendea
mendae medean medena medaen medane mednae mednea meedan meedna meeadn meeand
meenad meenda meaedn meaend meaden meadne meande meaned menead meneda menaed
menade mendae mendea mndeea mndeae mndeea mndeae mndaee mndaee mnedea mnedae
mneeda mneead mneaed mneade mneeda mneead mnedea mnedae mneade mneaed mnaeed
mnaede mnaeed mnaede mnadee mnadee

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