easy ciphers

Easy Ciphers Tools:
cryptography lectures
popular ciphers:



















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: ptosis
cipher variations:
quptjt rvquku swrvlv txswmw uytxnx
vzuyoy wavzpz xbwaqa ycxbrb zdycsc
aezdtd bfaeue cgbfvf dhcgwg eidhxh
fjeiyi gkfjzj hlgkak imhlbl jnimcm
kojndn lpkoeo mqlpfp nrmqgq osnrhr

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.)
Read more ...
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: ptosis
Cipher: kglhrh

Read more ...


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: ptosis

Read more ...


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: ptosis
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,

Read more ...


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: ptosis
Cipher: cgbfvf

Read more ...


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: ptosis
Cipher: 534443344234

Extended Methods:
Method #1

Plaintext: ptosis
method variations:

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

Read more ...
Method #3

Plaintext: ptosis
method variations:
stntmy tntmys ntmyst
tmystn mystnt ystntm

Read more ...[RUS] , [EN]


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: ptosis

all 720 cipher variations:
ptosis ptossi ptoiss ptoiss ptosis ptossi ptsois ptsosi ptsios ptsiso ptssio
ptssoi ptisos ptisso ptioss ptioss ptisos ptisso ptssio ptssoi ptsiso ptsios
ptsois ptsosi potsis potssi potiss potiss potsis potssi postis postsi posits
posist possit possti poists poisst poitss poitss poists poisst possit possti
posist posits postis postsi psotis psotsi psoits psoist psosit psosti pstois
pstosi pstios pstiso pstsio pstsoi psitos psitso psiots psiost psisot psisto
psstio psstoi pssito pssiot pssoit pssoti piosts piosst piotss piotss piosts
piosst pisots pisost pistos pistso pissto pissot pitsos pitsso pitoss pitoss
pitsos pitsso pissto pissot pistso pistos pisots pisost psosit psosti psoist
psoits psotis psotsi pssoit pssoti pssiot pssito psstio psstoi psisot psisto
psiost psiots psitos psitso pstsio pstsoi pstiso pstios pstois pstosi tposis
tpossi tpoiss tpoiss tposis tpossi tpsois tpsosi tpsios tpsiso tpssio tpssoi
tpisos tpisso tpioss tpioss tpisos tpisso tpssio tpssoi tpsiso tpsios tpsois
tpsosi topsis topssi topiss topiss topsis topssi tospis tospsi tosips tosisp
tossip tosspi toisps toissp toipss toipss toisps toissp tossip tosspi tosisp
tosips tospis tospsi tsopis tsopsi tsoips tsoisp tsosip tsospi tspois tsposi
tspios tspiso tspsio tspsoi tsipos tsipso tsiops tsiosp tsisop tsispo tsspio
tsspoi tssipo tssiop tssoip tssopi tiosps tiossp tiopss tiopss tiosps tiossp
tisops tisosp tispos tispso tisspo tissop tipsos tipsso tiposs tiposs tipsos
tipsso tisspo tissop tispso tispos tisops tisosp tsosip tsospi tsoisp tsoips
tsopis tsopsi tssoip tssopi tssiop tssipo tsspio tsspoi tsisop tsispo tsiosp
tsiops tsipos tsipso tspsio tspsoi tspiso tspios tspois tsposi otpsis otpssi
otpiss otpiss otpsis otpssi otspis otspsi otsips otsisp otssip otsspi otisps
otissp otipss otipss otisps otissp otssip otsspi otsisp otsips otspis otspsi
optsis optssi optiss optiss optsis optssi opstis opstsi opsits opsist opssit
opssti opists opisst opitss opitss opists opisst opssit opssti opsist opsits
opstis opstsi osptis osptsi ospits ospist ospsit ospsti ostpis ostpsi ostips
ostisp ostsip ostspi ositps ositsp osipts osipst osispt osistp osstip osstpi
ossitp ossipt osspit osspti oipsts oipsst oiptss oiptss oipsts oipsst oispts
oispst oistps oistsp oisstp oisspt oitsps oitssp oitpss oitpss oitsps oitssp
oisstp oisspt oistsp oistps oispts oispst ospsit ospsti ospist ospits osptis
osptsi osspit osspti ossipt ossitp osstip osstpi osispt osistp osipst osipts
ositps ositsp ostsip ostspi ostisp ostips ostpis ostpsi stopis stopsi stoips
stoisp stosip stospi stpois stposi stpios stpiso stpsio stpsoi stipos stipso
stiops stiosp stisop stispo stspio stspoi stsipo stsiop stsoip stsopi sotpis
sotpsi sotips sotisp sotsip sotspi soptis soptsi sopits sopist sopsit sopsti
soipts soipst soitps soitsp soistp soispt sospit sospti sosipt sositp sostip
sostpi spotis spotsi spoits spoist sposit sposti sptois sptosi sptios sptiso
sptsio sptsoi spitos spitso spiots spiost spisot spisto spstio spstoi spsito
spsiot spsoit spsoti siopts siopst siotps siotsp siostp siospt sipots sipost
siptos siptso sipsto sipsot sitpos sitpso sitops sitosp sitsop sitspo sispto
sispot sistpo sistop sisotp sisopt ssopit ssopti ssoipt ssoitp ssotip ssotpi
sspoit sspoti sspiot sspito ssptio ssptoi ssipot ssipto ssiopt ssiotp ssitop
ssitpo sstpio sstpoi sstipo sstiop sstoip sstopi itosps itossp itopss itopss
itosps itossp itsops itsosp itspos itspso itsspo itssop itpsos itpsso itposs
itposs itpsos itpsso itsspo itssop itspso itspos itsops itsosp iotsps iotssp
iotpss iotpss iotsps iotssp iostps iostsp iospts iospst iosspt iosstp iopsts
iopsst ioptss ioptss iopsts iopsst iosspt iosstp iospst iospts iostps iostsp
isotps isotsp isopts isopst isospt isostp istops istosp istpos istpso istspo
istsop isptos isptso ispots ispost ispsot ispsto isstpo isstop isspto isspot
issopt issotp iposts iposst ipotss ipotss iposts iposst ipsots ipsost ipstos
ipstso ipssto ipssot iptsos iptsso iptoss iptoss iptsos iptsso ipssto ipssot
ipstso ipstos ipsots ipsost isospt isostp isopst isopts isotps isotsp issopt
issotp isspot isspto isstpo isstop ispsot ispsto ispost ispots isptos isptso
istspo istsop istpso istpos istops istosp stosip stospi stoisp stoips stopis
stopsi stsoip stsopi stsiop stsipo stspio stspoi stisop stispo stiosp stiops
stipos stipso stpsio stpsoi stpiso stpios stpois stposi sotsip sotspi sotisp
sotips sotpis sotpsi sostip sostpi sositp sosipt sospit sospti soistp soispt
soitsp soitps soipts soipst sopsit sopsti sopist sopits soptis soptsi ssotip
ssotpi ssoitp ssoipt ssopit ssopti sstoip sstopi sstiop sstipo sstpio sstpoi
ssitop ssitpo ssiotp ssiopt ssipot ssipto ssptio ssptoi sspito sspiot sspoit
sspoti siostp siospt siotsp siotps siopts siopst sisotp sisopt sistop sistpo
sispto sispot sitsop sitspo sitosp sitops sitpos sitpso sipsto sipsot siptso
siptos sipots sipost sposit sposti spoist spoits spotis spotsi spsoit spsoti
spsiot spsito spstio spstoi spisot spisto spiost spiots spitos spitso sptsio
sptsoi sptiso sptios sptois sptosi

Read more ...[1] , [2] , [3]

History of cryptography
2011 Easy Ciphers. All rights reserved. contact us