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: merapi
cipher variations:
nfsbqj ogtcrk phudsl qivetm rjwfun
skxgvo tlyhwp umzixq vnajyr wobkzs
xpclat yqdmbu zrencv asfodw btgpex
cuhqfy dvirgz ewjsha fxktib gylujc
hzmvkd ianwle jboxmf kcpyng ldqzoh

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: merapi
Cipher: nvizkr

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: merapi

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: merapi
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: merapi
Cipher: zrencv

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: merapi
Cipher: 235124115342

Extended Methods:
Method #1

Plaintext: merapi
method variations:

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

Read more ...
Method #3

Plaintext: merapi
method variations:
xfdvsg fdvsgx dvsgxf
vsgxfd sgxfdv gxfdvs

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: merapi

all 720 cipher variations:
merapi meraip merpai merpia meripa meriap mearpi mearip meapri meapir meaipr
meairp mepari mepair meprai mepria mepira mepiar meiapr meiarp meipar meipra
meirpa meirap mreapi mreaip mrepai mrepia mreipa mreiap mraepi mraeip mrapei
mrapie mraipe mraiep mrpaei mrpaie mrpeai mrpeia mrpiea mrpiae mriape mriaep
mripae mripea mriepa mrieap marepi mareip marpei marpie maripe mariep maerpi
maerip maepri maepir maeipr maeirp maperi mapeir maprei maprie mapire mapier
maiepr maierp maiper maipre mairpe mairep mpraei mpraie mpreai mpreia mpriea
mpriae mparei mparie mpaeri mpaeir mpaier mpaire mpeari mpeair mperai mperia
mpeira mpeiar mpiaer mpiare mpiear mpiera mpirea mpirae mirape miraep mirpae
mirpea mirepa mireap miarpe miarep miapre miaper miaepr miaerp mipare mipaer
miprae miprea mipera mipear mieapr miearp miepar miepra mierpa mierap emrapi
emraip emrpai emrpia emripa emriap emarpi emarip emapri emapir emaipr emairp
empari empair emprai empria empira empiar emiapr emiarp emipar emipra emirpa
emirap ermapi ermaip ermpai ermpia ermipa ermiap erampi eramip erapmi erapim
eraipm eraimp erpami erpaim erpmai erpmia erpima erpiam eriapm eriamp eripam
eripma erimpa erimap earmpi earmip earpmi earpim earipm earimp eamrpi eamrip
eampri eampir eamipr eamirp eapmri eapmir eaprmi eaprim eapirm eapimr eaimpr
eaimrp eaipmr eaiprm eairpm eairmp eprami epraim eprmai eprmia eprima epriam
eparmi eparim epamri epamir epaimr epairm epmari epmair epmrai epmria epmira
epmiar epiamr epiarm epimar epimra epirma epiram eirapm eiramp eirpam eirpma
eirmpa eirmap eiarpm eiarmp eiaprm eiapmr eiampr eiamrp eiparm eipamr eipram
eiprma eipmra eipmar eimapr eimarp eimpar eimpra eimrpa eimrap remapi remaip
rempai rempia remipa remiap reampi reamip reapmi reapim reaipm reaimp repami
repaim repmai repmia repima repiam reiapm reiamp reipam reipma reimpa reimap
rmeapi rmeaip rmepai rmepia rmeipa rmeiap rmaepi rmaeip rmapei rmapie rmaipe
rmaiep rmpaei rmpaie rmpeai rmpeia rmpiea rmpiae rmiape rmiaep rmipae rmipea
rmiepa rmieap ramepi rameip rampei rampie ramipe ramiep raempi raemip raepmi
raepim raeipm raeimp rapemi rapeim rapmei rapmie rapime rapiem raiepm raiemp
raipem raipme raimpe raimep rpmaei rpmaie rpmeai rpmeia rpmiea rpmiae rpamei
rpamie rpaemi rpaeim rpaiem rpaime rpeami rpeaim rpemai rpemia rpeima rpeiam
rpiaem rpiame rpieam rpiema rpimea rpimae rimape rimaep rimpae rimpea rimepa
rimeap riampe riamep riapme riapem riaepm riaemp ripame ripaem ripmae ripmea
ripema ripeam rieapm rieamp riepam riepma riempa riemap aermpi aermip aerpmi
aerpim aeripm aerimp aemrpi aemrip aempri aempir aemipr aemirp aepmri aepmir
aeprmi aeprim aepirm aepimr aeimpr aeimrp aeipmr aeiprm aeirpm aeirmp arempi
aremip arepmi arepim areipm areimp armepi armeip armpei armpie armipe armiep
arpmei arpmie arpemi arpeim arpiem arpime arimpe arimep aripme aripem ariepm
ariemp amrepi amreip amrpei amrpie amripe amriep amerpi amerip amepri amepir
ameipr ameirp amperi ampeir amprei amprie ampire ampier amiepr amierp amiper
amipre amirpe amirep aprmei aprmie apremi apreim apriem aprime apmrei apmrie
apmeri apmeir apmier apmire apemri apemir apermi aperim apeirm apeimr apimer
apimre apiemr apierm apirem apirme airmpe airmep airpme airpem airepm airemp
aimrpe aimrep aimpre aimper aimepr aimerp aipmre aipmer aiprme aiprem aiperm
aipemr aiempr aiemrp aiepmr aieprm aierpm aiermp perami peraim permai permia
perima periam pearmi pearim peamri peamir peaimr peairm pemari pemair pemrai
pemria pemira pemiar peiamr peiarm peimar peimra peirma peiram preami preaim
premai premia preima preiam praemi praeim pramei pramie praime praiem prmaei
prmaie prmeai prmeia prmiea prmiae priame priaem primae primea priema prieam
paremi pareim parmei parmie parime pariem paermi paerim paemri paemir paeimr
paeirm pameri pameir pamrei pamrie pamire pamier paiemr paierm paimer paimre
pairme pairem pmraei pmraie pmreai pmreia pmriea pmriae pmarei pmarie pmaeri
pmaeir pmaier pmaire pmeari pmeair pmerai pmeria pmeira pmeiar pmiaer pmiare
pmiear pmiera pmirea pmirae pirame piraem pirmae pirmea pirema piream piarme
piarem piamre piamer piaemr piaerm pimare pimaer pimrae pimrea pimera pimear
pieamr piearm piemar piemra pierma pieram ierapm ieramp ierpam ierpma iermpa
iermap iearpm iearmp ieaprm ieapmr ieampr ieamrp ieparm iepamr iepram ieprma
iepmra iepmar iemapr iemarp iempar iempra iemrpa iemrap ireapm ireamp irepam
irepma irempa iremap iraepm iraemp irapem irapme irampe iramep irpaem irpame
irpeam irpema irpmea irpmae irmape irmaep irmpae irmpea irmepa irmeap iarepm
iaremp iarpem iarpme iarmpe iarmep iaerpm iaermp iaeprm iaepmr iaempr iaemrp
iaperm iapemr iaprem iaprme iapmre iapmer iamepr iamerp iamper iampre iamrpe
iamrep ipraem iprame ipream iprema iprmea iprmae iparem iparme ipaerm ipaemr
ipamer ipamre ipearm ipeamr iperam iperma ipemra ipemar ipmaer ipmare ipmear
ipmera ipmrea ipmrae imrape imraep imrpae imrpea imrepa imreap imarpe imarep
imapre imaper imaepr imaerp impare impaer imprae imprea impera impear imeapr
imearp imepar imepra imerpa imerap

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

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