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: freddi
cipher variations:
gsfeej htgffk iuhggl jvihhm kwjiin
lxkjjo mylkkp nzmllq oanmmr pbonns
qcpoot rdqppu serqqv tfsrrw ugtssx
vhutty wivuuz xjwvva ykxwwb zlyxxc
amzyyd bnazze cobaaf dpcbbg eqdcch

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: freddi
Cipher: uivwwr

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: freddi

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: freddi
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: freddi
Cipher: serqqv

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: freddi
Cipher: 122451414142

Extended Methods:
Method #1

Plaintext: freddi
method variations:

Method #2
Bifid cipher
The message is converted to its coordinates in the usual manner, but they are written vertically beneath:
f r e d d i 
1 2 5 4 4 4 
2 4 1 1 1 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: freddi
Cipher: futraf

Read more ...
Method #3

Plaintext: freddi
method variations:
gyqqqb yqqqbg qqqbgy
qqbgyq qbgyqq bgyqqq

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: freddi

all 720 cipher variations:
freddi fredid freddi fredid freidd freidd frdedi frdeid frddei frddie frdide
frdied frddei frddie frdedi frdeid frdied frdide fridde frided fridde frided
friedd friedd ferddi ferdid ferddi ferdid feridd feridd fedrdi fedrid feddri
feddir fedidr fedird feddri feddir fedrdi fedrid fedird fedidr feiddr feidrd
feiddr feidrd feirdd feirdd fderdi fderid fdedri fdedir fdeidr fdeird fdredi
fdreid fdrdei fdrdie fdride fdried fddrei fddrie fdderi fddeir fddier fddire
fdirde fdired fdidre fdider fdiedr fdierd fdedri fdedir fderdi fderid fdeird
fdeidr fdderi fddeir fddrei fddrie fddire fddier fdrdei fdrdie fdredi fdreid
fdried fdride fdidre fdider fdirde fdired fdierd fdiedr fieddr fiedrd fieddr
fiedrd fierdd fierdd fidedr fiderd fidder fiddre fidrde fidred fidder fiddre
fidedr fiderd fidred fidrde firdde firded firdde firded firedd firedd rfeddi
rfedid rfeddi rfedid rfeidd rfeidd rfdedi rfdeid rfddei rfddie rfdide rfdied
rfddei rfddie rfdedi rfdeid rfdied rfdide rfidde rfided rfidde rfided rfiedd
rfiedd refddi refdid refddi refdid refidd refidd redfdi redfid reddfi reddif
redidf redifd reddfi reddif redfdi redfid redifd redidf reiddf reidfd reiddf
reidfd reifdd reifdd rdefdi rdefid rdedfi rdedif rdeidf rdeifd rdfedi rdfeid
rdfdei rdfdie rdfide rdfied rddfei rddfie rddefi rddeif rddief rddife rdifde
rdifed rdidfe rdidef rdiedf rdiefd rdedfi rdedif rdefdi rdefid rdeifd rdeidf
rddefi rddeif rddfei rddfie rddife rddief rdfdei rdfdie rdfedi rdfeid rdfied
rdfide rdidfe rdidef rdifde rdifed rdiefd rdiedf rieddf riedfd rieddf riedfd
riefdd riefdd ridedf ridefd riddef riddfe ridfde ridfed riddef riddfe ridedf
ridefd ridfed ridfde rifdde rifded rifdde rifded rifedd rifedd erfddi erfdid
erfddi erfdid erfidd erfidd erdfdi erdfid erddfi erddif erdidf erdifd erddfi
erddif erdfdi erdfid erdifd erdidf eriddf eridfd eriddf eridfd erifdd erifdd
efrddi efrdid efrddi efrdid efridd efridd efdrdi efdrid efddri efddir efdidr
efdird efddri efddir efdrdi efdrid efdird efdidr efiddr efidrd efiddr efidrd
efirdd efirdd edfrdi edfrid edfdri edfdir edfidr edfird edrfdi edrfid edrdfi
edrdif edridf edrifd eddrfi eddrif eddfri eddfir eddifr eddirf edirdf edirfd
edidrf edidfr edifdr edifrd edfdri edfdir edfrdi edfrid edfird edfidr eddfri
eddfir eddrfi eddrif eddirf eddifr edrdfi edrdif edrfdi edrfid edrifd edridf
edidrf edidfr edirdf edirfd edifrd edifdr eifddr eifdrd eifddr eifdrd eifrdd
eifrdd eidfdr eidfrd eiddfr eiddrf eidrdf eidrfd eiddfr eiddrf eidfdr eidfrd
eidrfd eidrdf eirddf eirdfd eirddf eirdfd eirfdd eirfdd drefdi drefid dredfi
dredif dreidf dreifd drfedi drfeid drfdei drfdie drfide drfied drdfei drdfie
drdefi drdeif drdief drdife drifde drifed dridfe dridef driedf driefd derfdi
derfid derdfi derdif deridf derifd defrdi defrid defdri defdir defidr defird
dedfri dedfir dedrfi dedrif dedirf dedifr deifdr deifrd deidfr deidrf deirdf
deirfd dferdi dferid dfedri dfedir dfeidr dfeird dfredi dfreid dfrdei dfrdie
dfride dfried dfdrei dfdrie dfderi dfdeir dfdier dfdire dfirde dfired dfidre
dfider dfiedr dfierd ddefri ddefir dderfi dderif ddeirf ddeifr ddferi ddfeir
ddfrei ddfrie ddfire ddfier ddrfei ddrfie ddrefi ddreif ddrief ddrife ddifre
ddifer ddirfe ddiref ddierf ddiefr diefdr diefrd diedfr diedrf dierdf dierfd
difedr diferd difder difdre difrde difred didfer didfre didefr diderf didref
didrfe dirfde dirfed dirdfe dirdef diredf direfd dredfi dredif drefdi drefid
dreifd dreidf drdefi drdeif drdfei drdfie drdife drdief drfdei drfdie drfedi
drfeid drfied drfide dridfe dridef drifde drifed driefd driedf derdfi derdif
derfdi derfid derifd deridf dedrfi dedrif dedfri dedfir dedifr dedirf defdri
defdir defrdi defrid defird defidr deidfr deidrf deifdr deifrd deirfd deirdf
dderfi dderif ddefri ddefir ddeifr ddeirf ddrefi ddreif ddrfei ddrfie ddrife
ddrief ddfrei ddfrie ddferi ddfeir ddfier ddfire ddirfe ddiref ddifre ddifer
ddiefr ddierf dfedri dfedir dferdi dferid dfeird dfeidr dfderi dfdeir dfdrei
dfdrie dfdire dfdier dfrdei dfrdie dfredi dfreid dfried dfride dfidre dfider
dfirde dfired dfierd dfiedr diedfr diedrf diefdr diefrd dierfd dierdf didefr
diderf didfer didfre didrfe didref difder difdre difedr diferd difred difrde
dirdfe dirdef dirfde dirfed direfd diredf ireddf iredfd ireddf iredfd irefdd
irefdd irdedf irdefd irddef irddfe irdfde irdfed irddef irddfe irdedf irdefd
irdfed irdfde irfdde irfded irfdde irfded irfedd irfedd ierddf ierdfd ierddf
ierdfd ierfdd ierfdd iedrdf iedrfd ieddrf ieddfr iedfdr iedfrd ieddrf ieddfr
iedrdf iedrfd iedfrd iedfdr iefddr iefdrd iefddr iefdrd iefrdd iefrdd iderdf
iderfd idedrf idedfr idefdr idefrd idredf idrefd idrdef idrdfe idrfde idrfed
iddref iddrfe idderf iddefr iddfer iddfre idfrde idfred idfdre idfder idfedr
idferd idedrf idedfr iderdf iderfd idefrd idefdr idderf iddefr iddref iddrfe
iddfre iddfer idrdef idrdfe idredf idrefd idrfed idrfde idfdre idfder idfrde
idfred idferd idfedr ifeddr ifedrd ifeddr ifedrd iferdd iferdd ifdedr ifderd
ifdder ifddre ifdrde ifdred ifdder ifddre ifdedr ifderd ifdred ifdrde ifrdde
ifrded ifrdde ifrded ifredd ifredd

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

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