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: clupea
cipher variations:
dmvqfb enwrgc foxshd gpytie hqzujf
iravkg jsbwlh ktcxmi ludynj mvezok
nwfapl oxgbqm pyhcrn qzidso rajetp
sbkfuq tclgvr udmhws venixt wfojyu
xgpkzv yhqlaw zirmbx ajsncy bktodz

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: clupea
Cipher: xofkvz

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: clupea

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: clupea
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: clupea
Cipher: pyhcrn

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: clupea
Cipher: 311354535111

Extended Methods:
Method #1

Plaintext: clupea
method variations:

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

Read more ...
Method #3

Plaintext: clupea
method variations:
axyxal xyxala yxalax
xalaxy alaxyx laxyxa

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: clupea

all 720 cipher variations:
clupea clupae cluepa clueap cluaep cluape clpuea clpuae clpeua clpeau clpaeu
clpaue clepua clepau cleupa cleuap cleaup cleapu clapeu clapue claepu claeup
clauep claupe culpea culpae culepa culeap culaep culape cuplea cuplae cupela
cupeal cupael cupale cuepla cuepal cuelpa cuelap cuealp cueapl cuapel cuaple
cuaepl cuaelp cualep cualpe cpulea cpulae cpuela cpueal cpuael cpuale cpluea
cpluae cpleua cpleau cplaeu cplaue cpelua cpelau cpeula cpeual cpeaul cpealu
cpaleu cpalue cpaelu cpaeul cpauel cpaule ceupla ceupal ceulpa ceulap ceualp
ceuapl cepula cepual ceplua ceplau cepalu cepaul celpua celpau celupa celuap
celaup celapu ceaplu ceapul cealpu cealup ceaulp ceaupl caupel cauple cauepl
cauelp caulep caulpe capuel capule capeul capelu capleu caplue caepul caeplu
caeupl caeulp caelup caelpu calpeu calpue calepu caleup caluep calupe lcupea
lcupae lcuepa lcueap lcuaep lcuape lcpuea lcpuae lcpeua lcpeau lcpaeu lcpaue
lcepua lcepau lceupa lceuap lceaup lceapu lcapeu lcapue lcaepu lcaeup lcauep
lcaupe lucpea lucpae lucepa luceap lucaep lucape lupcea lupcae lupeca lupeac
lupaec lupace luepca luepac luecpa luecap lueacp lueapc luapec luapce luaepc
luaecp luacep luacpe lpucea lpucae lpueca lpueac lpuaec lpuace lpcuea lpcuae
lpceua lpceau lpcaeu lpcaue lpecua lpecau lpeuca lpeuac lpeauc lpeacu lpaceu
lpacue lpaecu lpaeuc lpauec lpauce leupca leupac leucpa leucap leuacp leuapc
lepuca lepuac lepcua lepcau lepacu lepauc lecpua lecpau lecupa lecuap lecaup
lecapu leapcu leapuc leacpu leacup leaucp leaupc laupec laupce lauepc lauecp
laucep laucpe lapuec lapuce lapeuc lapecu lapceu lapcue laepuc laepcu laeupc
laeucp laecup laecpu lacpeu lacpue lacepu laceup lacuep lacupe ulcpea ulcpae
ulcepa ulceap ulcaep ulcape ulpcea ulpcae ulpeca ulpeac ulpaec ulpace ulepca
ulepac ulecpa ulecap uleacp uleapc ulapec ulapce ulaepc ulaecp ulacep ulacpe
uclpea uclpae uclepa ucleap uclaep uclape ucplea ucplae ucpela ucpeal ucpael
ucpale ucepla ucepal ucelpa ucelap ucealp uceapl ucapel ucaple ucaepl ucaelp
ucalep ucalpe upclea upclae upcela upceal upcael upcale uplcea uplcae upleca
upleac uplaec uplace upelca upelac upecla upecal upeacl upealc upalec upalce
upaelc upaecl upacel upacle uecpla uecpal ueclpa ueclap uecalp uecapl uepcla
uepcal ueplca ueplac uepalc uepacl uelpca uelpac uelcpa uelcap uelacp uelapc
ueaplc ueapcl uealpc uealcp ueaclp ueacpl uacpel uacple uacepl uacelp uaclep
uaclpe uapcel uapcle uapecl uapelc uaplec uaplce uaepcl uaeplc uaecpl uaeclp
uaelcp uaelpc ualpec ualpce ualepc ualecp ualcep ualcpe plucea plucae plueca
plueac pluaec pluace plcuea plcuae plceua plceau plcaeu plcaue plecua plecau
pleuca pleuac pleauc pleacu placeu placue plaecu plaeuc plauec plauce pulcea
pulcae puleca puleac pulaec pulace puclea puclae pucela puceal pucael pucale
puecla puecal puelca puelac puealc pueacl puacel puacle puaecl puaelc pualec
pualce pculea pculae pcuela pcueal pcuael pcuale pcluea pcluae pcleua pcleau
pclaeu pclaue pcelua pcelau pceula pceual pceaul pcealu pcaleu pcalue pcaelu
pcaeul pcauel pcaule peucla peucal peulca peulac peualc peuacl pecula pecual
peclua peclau pecalu pecaul pelcua pelcau peluca peluac pelauc pelacu peaclu
peacul pealcu pealuc peaulc peaucl paucel paucle pauecl pauelc paulec paulce
pacuel pacule paceul pacelu pacleu paclue paecul paeclu paeucl paeulc paeluc
paelcu palceu palcue palecu paleuc paluec paluce elupca elupac elucpa elucap
eluacp eluapc elpuca elpuac elpcua elpcau elpacu elpauc elcpua elcpau elcupa
elcuap elcaup elcapu elapcu elapuc elacpu elacup elaucp elaupc eulpca eulpac
eulcpa eulcap eulacp eulapc euplca euplac eupcla eupcal eupacl eupalc eucpla
eucpal euclpa euclap eucalp eucapl euapcl euaplc euacpl euaclp eualcp eualpc
epulca epulac epucla epucal epuacl epualc epluca epluac eplcua eplcau eplacu
eplauc epclua epclau epcula epcual epcaul epcalu epalcu epaluc epaclu epacul
epaucl epaulc ecupla ecupal eculpa eculap ecualp ecuapl ecpula ecpual ecplua
ecplau ecpalu ecpaul eclpua eclpau eclupa ecluap eclaup eclapu ecaplu ecapul
ecalpu ecalup ecaulp ecaupl eaupcl eauplc eaucpl eauclp eaulcp eaulpc eapucl
eapulc eapcul eapclu eaplcu eapluc eacpul eacplu eacupl eaculp eaclup eaclpu
ealpcu ealpuc ealcpu ealcup ealucp ealupc alupec alupce aluepc aluecp alucep
alucpe alpuec alpuce alpeuc alpecu alpceu alpcue alepuc alepcu aleupc aleucp
alecup alecpu alcpeu alcpue alcepu alceup alcuep alcupe aulpec aulpce aulepc
aulecp aulcep aulcpe auplec auplce aupelc aupecl aupcel aupcle aueplc auepcl
auelpc auelcp aueclp auecpl aucpel aucple aucepl aucelp auclep auclpe apulec
apulce apuelc apuecl apucel apucle apluec apluce apleuc aplecu aplceu aplcue
apeluc apelcu apeulc apeucl apecul apeclu apcleu apclue apcelu apceul apcuel
apcule aeuplc aeupcl aeulpc aeulcp aeuclp aeucpl aepulc aepucl aepluc aeplcu
aepclu aepcul aelpuc aelpcu aelupc aelucp aelcup aelcpu aecplu aecpul aeclpu
aeclup aeculp aecupl acupel acuple acuepl acuelp aculep aculpe acpuel acpule
acpeul acpelu acpleu acplue acepul aceplu aceupl aceulp acelup acelpu aclpeu
aclpue aclepu acleup acluep aclupe

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

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