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: pitufo
cipher variations:
qjuvgp rkvwhq slwxir tmxyjs unyzkt
vozalu wpabmv xqbcnw yrcdox zsdepy
atefqz bufgra cvghsb dwhitc exijud
fyjkve gzklwf halmxg ibmnyh jcnozi
kdopaj lepqbk mfqrcl ngrsdm ohsten

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: pitufo
Cipher: krgful

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: pitufo

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: pitufo
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: pitufo
Cipher: cvghsb

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: pitufo
Cipher: 534244541243

Extended Methods:
Method #1

Plaintext: pitufo
method variations:

Method #2
Bifid cipher
The message is converted to its coordinates in the usual manner, but they are written vertically beneath:
p i t u f o 
5 4 4 5 1 4 
3 2 4 4 2 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: pitufo
Cipher: uyqhtm

Read more ...
Method #3

Plaintext: pitufo
method variations:
srydrx rydrxs ydrxsr
drxsry rxsryd xsrydr

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: pitufo

all 720 cipher variations:
pitufo pituof pitfuo pitfou pitofu pitouf piutfo piutof piufto piufot piuoft
piuotf pifuto pifuot piftuo piftou pifotu pifout piouft pioutf piofut pioftu
piotfu piotuf ptiufo ptiuof ptifuo ptifou ptiofu ptiouf ptuifo ptuiof ptufio
ptufoi ptuofi ptuoif ptfuio ptfuoi ptfiuo ptfiou ptfoiu ptfoui ptoufi ptouif
ptofui ptofiu ptoifu ptoiuf putifo putiof putfio putfoi putofi putoif puitfo
puitof puifto puifot puioft puiotf pufito pufiot puftio puftoi pufoti pufoit
puoift puoitf puofit puofti puotfi puotif pftuio pftuoi pftiuo pftiou pftoiu
pftoui pfutio pfutoi pfuito pfuiot pfuoit pfuoti pfiuto pfiuot pfituo pfitou
pfiotu pfiout pfouit pfouti pfoiut pfoitu pfotiu pfotui potufi potuif potfui
potfiu potifu potiuf poutfi poutif poufti poufit pouift pouitf pofuti pofuit
poftui poftiu pofitu pofiut poiuft poiutf poifut poiftu poitfu poituf iptufo
iptuof iptfuo iptfou iptofu iptouf iputfo iputof ipufto ipufot ipuoft ipuotf
ipfuto ipfuot ipftuo ipftou ipfotu ipfout ipouft ipoutf ipofut ipoftu ipotfu
ipotuf itpufo itpuof itpfuo itpfou itpofu itpouf itupfo itupof itufpo itufop
ituofp ituopf itfupo itfuop itfpuo itfpou itfopu itfoup itoufp itoupf itofup
itofpu itopfu itopuf iutpfo iutpof iutfpo iutfop iutofp iutopf iuptfo iuptof
iupfto iupfot iupoft iupotf iufpto iufpot iuftpo iuftop iufotp iufopt iuopft
iuoptf iuofpt iuoftp iuotfp iuotpf iftupo iftuop iftpuo iftpou iftopu iftoup
ifutpo ifutop ifupto ifupot ifuopt ifuotp ifputo ifpuot ifptuo ifptou ifpotu
ifpout ifoupt ifoutp ifoput ifoptu ifotpu ifotup iotufp iotupf iotfup iotfpu
iotpfu iotpuf ioutfp ioutpf iouftp ioufpt ioupft iouptf iofutp iofupt ioftup
ioftpu iofptu iofput iopuft ioputf iopfut iopftu ioptfu ioptuf tipufo tipuof
tipfuo tipfou tipofu tipouf tiupfo tiupof tiufpo tiufop tiuofp tiuopf tifupo
tifuop tifpuo tifpou tifopu tifoup tioufp tioupf tiofup tiofpu tiopfu tiopuf
tpiufo tpiuof tpifuo tpifou tpiofu tpiouf tpuifo tpuiof tpufio tpufoi tpuofi
tpuoif tpfuio tpfuoi tpfiuo tpfiou tpfoiu tpfoui tpoufi tpouif tpofui tpofiu
tpoifu tpoiuf tupifo tupiof tupfio tupfoi tupofi tupoif tuipfo tuipof tuifpo
tuifop tuiofp tuiopf tufipo tufiop tufpio tufpoi tufopi tufoip tuoifp tuoipf
tuofip tuofpi tuopfi tuopif tfpuio tfpuoi tfpiuo tfpiou tfpoiu tfpoui tfupio
tfupoi tfuipo tfuiop tfuoip tfuopi tfiupo tfiuop tfipuo tfipou tfiopu tfioup
tfouip tfoupi tfoiup tfoipu tfopiu tfopui topufi topuif topfui topfiu topifu
topiuf toupfi toupif toufpi toufip touifp touipf tofupi tofuip tofpui tofpiu
tofipu tofiup toiufp toiupf toifup toifpu toipfu toipuf uitpfo uitpof uitfpo
uitfop uitofp uitopf uiptfo uiptof uipfto uipfot uipoft uipotf uifpto uifpot
uiftpo uiftop uifotp uifopt uiopft uioptf uiofpt uioftp uiotfp uiotpf utipfo
utipof utifpo utifop utiofp utiopf utpifo utpiof utpfio utpfoi utpofi utpoif
utfpio utfpoi utfipo utfiop utfoip utfopi utopfi utopif utofpi utofip utoifp
utoipf uptifo uptiof uptfio uptfoi uptofi uptoif upitfo upitof upifto upifot
upioft upiotf upfito upfiot upftio upftoi upfoti upfoit upoift upoitf upofit
upofti upotfi upotif uftpio uftpoi uftipo uftiop uftoip uftopi ufptio ufptoi
ufpito ufpiot ufpoit ufpoti ufipto ufipot ufitpo ufitop ufiotp ufiopt ufopit
ufopti ufoipt ufoitp ufotip ufotpi uotpfi uotpif uotfpi uotfip uotifp uotipf
uoptfi uoptif uopfti uopfit uopift uopitf uofpti uofpit uoftpi uoftip uofitp
uofipt uoipft uoiptf uoifpt uoiftp uoitfp uoitpf fitupo fituop fitpuo fitpou
fitopu fitoup fiutpo fiutop fiupto fiupot fiuopt fiuotp fiputo fipuot fiptuo
fiptou fipotu fipout fioupt fioutp fioput fioptu fiotpu fiotup ftiupo ftiuop
ftipuo ftipou ftiopu ftioup ftuipo ftuiop ftupio ftupoi ftuopi ftuoip ftpuio
ftpuoi ftpiuo ftpiou ftpoiu ftpoui ftoupi ftouip ftopui ftopiu ftoipu ftoiup
futipo futiop futpio futpoi futopi futoip fuitpo fuitop fuipto fuipot fuiopt
fuiotp fupito fupiot fuptio fuptoi fupoti fupoit fuoipt fuoitp fuopit fuopti
fuotpi fuotip fptuio fptuoi fptiuo fptiou fptoiu fptoui fputio fputoi fpuito
fpuiot fpuoit fpuoti fpiuto fpiuot fpituo fpitou fpiotu fpiout fpouit fpouti
fpoiut fpoitu fpotiu fpotui fotupi fotuip fotpui fotpiu fotipu fotiup foutpi
foutip foupti foupit fouipt fouitp foputi fopuit foptui foptiu fopitu fopiut
foiupt foiutp foiput foiptu foitpu foitup oitufp oitupf oitfup oitfpu oitpfu
oitpuf oiutfp oiutpf oiuftp oiufpt oiupft oiuptf oifutp oifupt oiftup oiftpu
oifptu oifput oipuft oiputf oipfut oipftu oiptfu oiptuf otiufp otiupf otifup
otifpu otipfu otipuf otuifp otuipf otufip otufpi otupfi otupif otfuip otfupi
otfiup otfipu otfpiu otfpui otpufi otpuif otpfui otpfiu otpifu otpiuf outifp
outipf outfip outfpi outpfi outpif ouitfp ouitpf ouiftp ouifpt ouipft ouiptf
oufitp oufipt ouftip ouftpi oufpti oufpit oupift oupitf oupfit oupfti ouptfi
ouptif oftuip oftupi oftiup oftipu oftpiu oftpui ofutip ofutpi ofuitp ofuipt
ofupit ofupti ofiutp ofiupt ofitup ofitpu ofiptu ofiput ofpuit ofputi ofpiut
ofpitu ofptiu ofptui optufi optuif optfui optfiu optifu optiuf oputfi oputif
opufti opufit opuift opuitf opfuti opfuit opftui opftiu opfitu opfiut opiuft
opiutf opifut opiftu opitfu opituf

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

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