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: certus
cipher variations:
dfsuvt egtvwu fhuwxv givxyw hjwyzx
ikxzay jlyabz kmzbca lnacdb mobdec
npcefd oqdfge preghf qsfhig rtgijh
suhjki tviklj uwjlmk vxkmnl wylnom
xzmopn yanpqo zboqrp acprsq bdqstr

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: certus
Cipher: xvigfh

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: certus

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: certus
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: certus
Cipher: preghf

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: certus
Cipher: 315124445434

Extended Methods:
Method #1

Plaintext: certus
method variations:

Method #2
Bifid cipher
The message is converted to its coordinates in the usual manner, but they are written vertically beneath:
c e r t u s 
3 5 2 4 5 3 
1 1 4 4 4 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: certus
Cipher: xrpatt

Read more ...
Method #3

Plaintext: certus
method variations:
vftyoo ftyoov tyoovf
yoovft oovfty ovftyo

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: certus

all 720 cipher variations:
certus certsu ceruts cerust cersut cerstu cetrus cetrsu ceturs cetusr cetsur
cetsru ceutrs ceutsr ceurts ceurst ceusrt ceustr cestur cestru cesutr cesurt
cesrut cesrtu cretus cretsu creuts creust cresut crestu crteus crtesu crtues
crtuse crtsue crtseu crutes crutse cruets cruest cruset cruste crstue crsteu
crsute crsuet crseut crsetu ctreus ctresu ctrues ctruse ctrsue ctrseu cterus
ctersu cteurs cteusr ctesur ctesru ctuers ctuesr ctures cturse ctusre ctuser
ctseur ctseru ctsuer ctsure ctsrue ctsreu curtes curtse curets curest curset
curste cutres cutrse cuters cutesr cutser cutsre cuetrs cuetsr cuerts cuerst
cuesrt cuestr custer custre cusetr cusert cusret cusrte csrtue csrteu csrute
csruet csreut csretu cstrue cstreu csture cstuer csteur csteru csutre csuter
csurte csuret csuert csuetr csetur csetru cseutr cseurt cserut csertu ecrtus
ecrtsu ecruts ecrust ecrsut ecrstu ectrus ectrsu ecturs ectusr ectsur ectsru
ecutrs ecutsr ecurts ecurst ecusrt ecustr ecstur ecstru ecsutr ecsurt ecsrut
ecsrtu erctus erctsu ercuts ercust ercsut ercstu ertcus ertcsu ertucs ertusc
ertsuc ertscu erutcs erutsc eructs erucst erusct erustc erstuc erstcu ersutc
ersuct erscut ersctu etrcus etrcsu etrucs etrusc etrsuc etrscu etcrus etcrsu
etcurs etcusr etcsur etcsru etucrs etucsr eturcs etursc etusrc etuscr etscur
etscru etsucr etsurc etsruc etsrcu eurtcs eurtsc eurcts eurcst eursct eurstc
eutrcs eutrsc eutcrs eutcsr eutscr eutsrc euctrs euctsr eucrts eucrst eucsrt
eucstr eustcr eustrc eusctr euscrt eusrct eusrtc esrtuc esrtcu esrutc esruct
esrcut esrctu estruc estrcu esturc estucr estcur estcru esutrc esutcr esurtc
esurct esucrt esuctr esctur esctru escutr escurt escrut escrtu rectus rectsu
recuts recust recsut recstu retcus retcsu retucs retusc retsuc retscu reutcs
reutsc reucts reucst reusct reustc restuc restcu resutc resuct rescut resctu
rcetus rcetsu rceuts rceust rcesut rcestu rcteus rctesu rctues rctuse rctsue
rctseu rcutes rcutse rcuets rcuest rcuset rcuste rcstue rcsteu rcsute rcsuet
rcseut rcsetu rtceus rtcesu rtcues rtcuse rtcsue rtcseu rtecus rtecsu rteucs
rteusc rtesuc rtescu rtuecs rtuesc rtuces rtucse rtusce rtusec rtseuc rtsecu
rtsuec rtsuce rtscue rtsceu ructes ructse rucets rucest rucset rucste rutces
rutcse rutecs rutesc rutsec rutsce ruetcs ruetsc ruects ruecst ruesct ruestc
rustec rustce rusetc rusect ruscet ruscte rsctue rscteu rscute rscuet rsceut
rscetu rstcue rstceu rstuce rstuec rsteuc rstecu rsutce rsutec rsucte rsucet
rsuect rsuetc rsetuc rsetcu rseutc rseuct rsecut rsectu tercus tercsu terucs
terusc tersuc terscu tecrus tecrsu tecurs tecusr tecsur tecsru teucrs teucsr
teurcs teursc teusrc teuscr tescur tescru tesucr tesurc tesruc tesrcu trecus
trecsu treucs treusc tresuc trescu trceus trcesu trcues trcuse trcsue trcseu
truces trucse truecs truesc trusec trusce trscue trsceu trsuce trsuec trseuc
trsecu tcreus tcresu tcrues tcruse tcrsue tcrseu tcerus tcersu tceurs tceusr
tcesur tcesru tcuers tcuesr tcures tcurse tcusre tcuser tcseur tcseru tcsuer
tcsure tcsrue tcsreu turces turcse turecs turesc tursec tursce tucres tucrse
tucers tucesr tucser tucsre tuecrs tuecsr tuercs tuersc tuesrc tuescr tuscer
tuscre tusecr tuserc tusrec tusrce tsrcue tsrceu tsruce tsruec tsreuc tsrecu
tscrue tscreu tscure tscuer tsceur tsceru tsucre tsucer tsurce tsurec tsuerc
tsuecr tsecur tsecru tseucr tseurc tseruc tsercu uertcs uertsc uercts uercst
uersct uerstc uetrcs uetrsc uetcrs uetcsr uetscr uetsrc uectrs uectsr uecrts
uecrst uecsrt uecstr uestcr uestrc uesctr uescrt uesrct uesrtc uretcs uretsc
urects urecst uresct urestc urtecs urtesc urtces urtcse urtsce urtsec urctes
urctse urcets urcest urcset urcste urstce urstec urscte urscet ursect ursetc
utrecs utresc utrces utrcse utrsce utrsec utercs utersc utecrs utecsr utescr
utesrc utcers utcesr utcres utcrse utcsre utcser utsecr utserc utscer utscre
utsrce utsrec ucrtes ucrtse ucrets ucrest ucrset ucrste uctres uctrse ucters
uctesr uctser uctsre ucetrs ucetsr ucerts ucerst ucesrt ucestr ucster ucstre
ucsetr ucsert ucsret ucsrte usrtce usrtec usrcte usrcet usrect usretc ustrce
ustrec ustcre ustcer ustecr usterc usctre uscter uscrte uscret uscert uscetr
usetcr usetrc usectr usecrt userct usertc sertuc sertcu serutc seruct sercut
serctu setruc setrcu seturc setucr setcur setcru seutrc seutcr seurtc seurct
seucrt seuctr sectur sectru secutr securt secrut secrtu sretuc sretcu sreutc
sreuct srecut srectu srteuc srtecu srtuec srtuce srtcue srtceu srutec srutce
sruetc sruect srucet sructe srctue srcteu srcute srcuet srceut srcetu streuc
strecu struec struce strcue strceu steruc stercu steurc steucr stecur stecru
stuerc stuecr sturec sturce stucre stucer stceur stceru stcuer stcure stcrue
stcreu surtec surtce suretc surect surcet surcte sutrec sutrce suterc sutecr
sutcer sutcre suetrc suetcr suertc suerct suecrt suectr sucter suctre sucetr
sucert sucret sucrte scrtue scrteu scrute scruet screut scretu sctrue sctreu
scture sctuer scteur scteru scutre scuter scurte scuret scuert scuetr scetur
scetru sceutr sceurt scerut scertu

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

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