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: habiri
cipher variations:
ibcjsj jcdktk kdelul lefmvm mfgnwn
nghoxo ohipyp pijqzq qjkrar rklsbs
slmtct tmnudu unovev vopwfw wpqxgx
xqryhy yrsziz zstaja atubkb buvclc
cvwdmd dwxene exyfof fyzgpg gzahqh

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: habiri
Cipher: szyrir

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: habiri

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: habiri
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: habiri
Cipher: unovev

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: habiri
Cipher: 321121422442

Extended Methods:
Method #1

Plaintext: habiri
method variations:

Method #2
Bifid cipher
The message is converted to its coordinates in the usual manner, but they are written vertically beneath:
h a b i r i 
3 1 2 4 2 4 
2 1 1 2 4 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: habiri
Cipher: crrbfi

Read more ...
Method #3

Plaintext: habiri
method variations:
bfqgtm fqgtmb qgtmbf
gtmbfq tmbfqg mbfqgt

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: habiri

all 720 cipher variations:
habiri habiir habrii habrii habiri habiir haibri haibir hairbi hairib haiirb
haiibr haribi hariib harbii harbii haribi hariib haiirb haiibr hairib hairbi
haibri haibir hbairi hbaiir hbarii hbarii hbairi hbaiir hbiari hbiair hbirai
hbiria hbiira hbiiar hbriai hbriia hbraii hbraii hbriai hbriia hbiira hbiiar
hbiria hbirai hbiari hbiair hibari hibair hibrai hibria hibira hibiar hiabri
hiabir hiarbi hiarib hiairb hiaibr hirabi hiraib hirbai hirbia hiriba hiriab
hiiarb hiiabr hiirab hiirba hiibra hiibar hrbiai hrbiia hrbaii hrbaii hrbiai
hrbiia hribai hribia hriabi hriaib hriiab hriiba hraibi hraiib hrabii hrabii
hraibi hraiib hriiab hriiba hriaib hriabi hribai hribia hibira hibiar hibria
hibrai hibari hibair hiibra hiibar hiirba hiirab hiiarb hiiabr hiriba hiriab
hirbia hirbai hirabi hiraib hiairb hiaibr hiarib hiarbi hiabri hiabir ahbiri
ahbiir ahbrii ahbrii ahbiri ahbiir ahibri ahibir ahirbi ahirib ahiirb ahiibr
ahribi ahriib ahrbii ahrbii ahribi ahriib ahiirb ahiibr ahirib ahirbi ahibri
ahibir abhiri abhiir abhrii abhrii abhiri abhiir abihri abihir abirhi abirih
abiirh abiihr abrihi abriih abrhii abrhii abrihi abriih abiirh abiihr abirih
abirhi abihri abihir aibhri aibhir aibrhi aibrih aibirh aibihr aihbri aihbir
aihrbi aihrib aihirb aihibr airhbi airhib airbhi airbih airibh airihb aiihrb
aiihbr aiirhb aiirbh aiibrh aiibhr arbihi arbiih arbhii arbhii arbihi arbiih
aribhi aribih arihbi arihib ariihb ariibh arhibi arhiib arhbii arhbii arhibi
arhiib ariihb ariibh arihib arihbi aribhi aribih aibirh aibihr aibrih aibrhi
aibhri aibhir aiibrh aiibhr aiirbh aiirhb aiihrb aiihbr airibh airihb airbih
airbhi airhbi airhib aihirb aihibr aihrib aihrbi aihbri aihbir bahiri bahiir
bahrii bahrii bahiri bahiir baihri baihir bairhi bairih baiirh baiihr barihi
bariih barhii barhii barihi bariih baiirh baiihr bairih bairhi baihri baihir
bhairi bhaiir bharii bharii bhairi bhaiir bhiari bhiair bhirai bhiria bhiira
bhiiar bhriai bhriia bhraii bhraii bhriai bhriia bhiira bhiiar bhiria bhirai
bhiari bhiair bihari bihair bihrai bihria bihira bihiar biahri biahir biarhi
biarih biairh biaihr birahi biraih birhai birhia biriha biriah biiarh biiahr
biirah biirha biihra biihar brhiai brhiia brhaii brhaii brhiai brhiia brihai
brihia briahi briaih briiah briiha braihi braiih brahii brahii braihi braiih
briiah briiha briaih briahi brihai brihia bihira bihiar bihria bihrai bihari
bihair biihra biihar biirha biirah biiarh biiahr biriha biriah birhia birhai
birahi biraih biairh biaihr biarih biarhi biahri biahir iabhri iabhir iabrhi
iabrih iabirh iabihr iahbri iahbir iahrbi iahrib iahirb iahibr iarhbi iarhib
iarbhi iarbih iaribh iarihb iaihrb iaihbr iairhb iairbh iaibrh iaibhr ibahri
ibahir ibarhi ibarih ibairh ibaihr ibhari ibhair ibhrai ibhria ibhira ibhiar
ibrhai ibrhia ibrahi ibraih ibriah ibriha ibihra ibihar ibirha ibirah ibiarh
ibiahr ihbari ihbair ihbrai ihbria ihbira ihbiar ihabri ihabir iharbi iharib
ihairb ihaibr ihrabi ihraib ihrbai ihrbia ihriba ihriab ihiarb ihiabr ihirab
ihirba ihibra ihibar irbhai irbhia irbahi irbaih irbiah irbiha irhbai irhbia
irhabi irhaib irhiab irhiba irahbi irahib irabhi irabih iraibh iraihb irihab
irihba iriahb iriabh iribah iribha iibhra iibhar iibrha iibrah iibarh iibahr
iihbra iihbar iihrba iihrab iiharb iihabr iirhba iirhab iirbha iirbah iirabh
iirahb iiahrb iiahbr iiarhb iiarbh iiabrh iiabhr rabihi rabiih rabhii rabhii
rabihi rabiih raibhi raibih raihbi raihib raiihb raiibh rahibi rahiib rahbii
rahbii rahibi rahiib raiihb raiibh raihib raihbi raibhi raibih rbaihi rbaiih
rbahii rbahii rbaihi rbaiih rbiahi rbiaih rbihai rbihia rbiiha rbiiah rbhiai
rbhiia rbhaii rbhaii rbhiai rbhiia rbiiha rbiiah rbihia rbihai rbiahi rbiaih
ribahi ribaih ribhai ribhia ribiha ribiah riabhi riabih riahbi riahib riaihb
riaibh rihabi rihaib rihbai rihbia rihiba rihiab riiahb riiabh riihab riihba
riibha riibah rhbiai rhbiia rhbaii rhbaii rhbiai rhbiia rhibai rhibia rhiabi
rhiaib rhiiab rhiiba rhaibi rhaiib rhabii rhabii rhaibi rhaiib rhiiab rhiiba
rhiaib rhiabi rhibai rhibia ribiha ribiah ribhia ribhai ribahi ribaih riibha
riibah riihba riihab riiahb riiabh rihiba rihiab rihbia rihbai rihabi rihaib
riaihb riaibh riahib riahbi riabhi riabih iabirh iabihr iabrih iabrhi iabhri
iabhir iaibrh iaibhr iairbh iairhb iaihrb iaihbr iaribh iarihb iarbih iarbhi
iarhbi iarhib iahirb iahibr iahrib iahrbi iahbri iahbir ibairh ibaihr ibarih
ibarhi ibahri ibahir ibiarh ibiahr ibirah ibirha ibihra ibihar ibriah ibriha
ibraih ibrahi ibrhai ibrhia ibhira ibhiar ibhria ibhrai ibhari ibhair iibarh
iibahr iibrah iibrha iibhra iibhar iiabrh iiabhr iiarbh iiarhb iiahrb iiahbr
iirabh iirahb iirbah iirbha iirhba iirhab iiharb iihabr iihrab iihrba iihbra
iihbar irbiah irbiha irbaih irbahi irbhai irbhia iribah iribha iriabh iriahb
irihab irihba iraibh iraihb irabih irabhi irahbi irahib irhiab irhiba irhaib
irhabi irhbai irhbia ihbira ihbiar ihbria ihbrai ihbari ihbair ihibra ihibar
ihirba ihirab ihiarb ihiabr ihriba ihriab ihrbia ihrbai ihrabi ihraib ihairb
ihaibr iharib iharbi ihabri ihabir

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

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