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: hydric
cipher variations:
izesjd jaftke kbgulf lchvmg mdiwnh
nejxoi ofkypj pglzqk qhmarl rinbsm
sjoctn tkpduo ulqevp vmrfwq wnsgxr
xothys ypuizt zqvjau arwkbv bsxlcw
ctymdx duzney evaofz fwbpga gxcqhb

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: hydric
Cipher: sbwirx

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: hydric

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: hydric
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: hydric
Cipher: ulqevp

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: hydric
Cipher: 324541244231

Extended Methods:
Method #1

Plaintext: hydric
method variations:

Method #2
Bifid cipher
The message is converted to its coordinates in the usual manner, but they are written vertically beneath:
h y d r i c 
3 4 4 2 4 3 
2 5 1 4 2 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: hydric
Cipher: siowqb

Read more ...
Method #3

Plaintext: hydric
method variations:
ruftml uftmlr ftmlru
tmlruf mlruft lruftm

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: hydric

all 720 cipher variations:
hydric hydrci hydirc hydicr hydcir hydcri hyrdic hyrdci hyridc hyricd hyrcid
hyrcdi hyirdc hyircd hyidrc hyidcr hyicdr hyicrd hycrid hycrdi hycird hycidr
hycdir hycdri hdyric hdyrci hdyirc hdyicr hdycir hdycri hdryic hdryci hdriyc
hdricy hdrciy hdrcyi hdiryc hdircy hdiyrc hdiycr hdicyr hdicry hdcriy hdcryi
hdciry hdciyr hdcyir hdcyri hrdyic hrdyci hrdiyc hrdicy hrdciy hrdcyi hrydic
hrydci hryidc hryicd hrycid hrycdi hriydc hriycd hridyc hridcy hricdy hricyd
hrcyid hrcydi hrciyd hrcidy hrcdiy hrcdyi hidryc hidrcy hidyrc hidycr hidcyr
hidcry hirdyc hirdcy hirydc hirycd hircyd hircdy hiyrdc hiyrcd hiydrc hiydcr
hiycdr hiycrd hicryd hicrdy hicyrd hicydr hicdyr hicdry hcdriy hcdryi hcdiry
hcdiyr hcdyir hcdyri hcrdiy hcrdyi hcridy hcriyd hcryid hcrydi hcirdy hciryd
hcidry hcidyr hciydr hciyrd hcyrid hcyrdi hcyird hcyidr hcydir hcydri yhdric
yhdrci yhdirc yhdicr yhdcir yhdcri yhrdic yhrdci yhridc yhricd yhrcid yhrcdi
yhirdc yhircd yhidrc yhidcr yhicdr yhicrd yhcrid yhcrdi yhcird yhcidr yhcdir
yhcdri ydhric ydhrci ydhirc ydhicr ydhcir ydhcri ydrhic ydrhci ydrihc ydrich
ydrcih ydrchi ydirhc ydirch ydihrc ydihcr ydichr ydicrh ydcrih ydcrhi ydcirh
ydcihr ydchir ydchri yrdhic yrdhci yrdihc yrdich yrdcih yrdchi yrhdic yrhdci
yrhidc yrhicd yrhcid yrhcdi yrihdc yrihcd yridhc yridch yricdh yrichd yrchid
yrchdi yrcihd yrcidh yrcdih yrcdhi yidrhc yidrch yidhrc yidhcr yidchr yidcrh
yirdhc yirdch yirhdc yirhcd yirchd yircdh yihrdc yihrcd yihdrc yihdcr yihcdr
yihcrd yicrhd yicrdh yichrd yichdr yicdhr yicdrh ycdrih ycdrhi ycdirh ycdihr
ycdhir ycdhri ycrdih ycrdhi ycridh ycrihd ycrhid ycrhdi ycirdh ycirhd ycidrh
ycidhr ycihdr ycihrd ychrid ychrdi ychird ychidr ychdir ychdri dyhric dyhrci
dyhirc dyhicr dyhcir dyhcri dyrhic dyrhci dyrihc dyrich dyrcih dyrchi dyirhc
dyirch dyihrc dyihcr dyichr dyicrh dycrih dycrhi dycirh dycihr dychir dychri
dhyric dhyrci dhyirc dhyicr dhycir dhycri dhryic dhryci dhriyc dhricy dhrciy
dhrcyi dhiryc dhircy dhiyrc dhiycr dhicyr dhicry dhcriy dhcryi dhciry dhciyr
dhcyir dhcyri drhyic drhyci drhiyc drhicy drhciy drhcyi dryhic dryhci dryihc
dryich drycih drychi driyhc driych drihyc drihcy drichy dricyh drcyih drcyhi
drciyh drcihy drchiy drchyi dihryc dihrcy dihyrc dihycr dihcyr dihcry dirhyc
dirhcy diryhc dirych dircyh dirchy diyrhc diyrch diyhrc diyhcr diychr diycrh
dicryh dicrhy dicyrh dicyhr dichyr dichry dchriy dchryi dchiry dchiyr dchyir
dchyri dcrhiy dcrhyi dcrihy dcriyh dcryih dcryhi dcirhy dciryh dcihry dcihyr
dciyhr dciyrh dcyrih dcyrhi dcyirh dcyihr dcyhir dcyhri rydhic rydhci rydihc
rydich rydcih rydchi ryhdic ryhdci ryhidc ryhicd ryhcid ryhcdi ryihdc ryihcd
ryidhc ryidch ryicdh ryichd rychid rychdi rycihd rycidh rycdih rycdhi rdyhic
rdyhci rdyihc rdyich rdycih rdychi rdhyic rdhyci rdhiyc rdhicy rdhciy rdhcyi
rdihyc rdihcy rdiyhc rdiych rdicyh rdichy rdchiy rdchyi rdcihy rdciyh rdcyih
rdcyhi rhdyic rhdyci rhdiyc rhdicy rhdciy rhdcyi rhydic rhydci rhyidc rhyicd
rhycid rhycdi rhiydc rhiycd rhidyc rhidcy rhicdy rhicyd rhcyid rhcydi rhciyd
rhcidy rhcdiy rhcdyi ridhyc ridhcy ridyhc ridych ridcyh ridchy rihdyc rihdcy
rihydc rihycd rihcyd rihcdy riyhdc riyhcd riydhc riydch riycdh riychd richyd
richdy ricyhd ricydh ricdyh ricdhy rcdhiy rcdhyi rcdihy rcdiyh rcdyih rcdyhi
rchdiy rchdyi rchidy rchiyd rchyid rchydi rcihdy rcihyd rcidhy rcidyh rciydh
rciyhd rcyhid rcyhdi rcyihd rcyidh rcydih rcydhi iydrhc iydrch iydhrc iydhcr
iydchr iydcrh iyrdhc iyrdch iyrhdc iyrhcd iyrchd iyrcdh iyhrdc iyhrcd iyhdrc
iyhdcr iyhcdr iyhcrd iycrhd iycrdh iychrd iychdr iycdhr iycdrh idyrhc idyrch
idyhrc idyhcr idychr idycrh idryhc idrych idrhyc idrhcy idrchy idrcyh idhryc
idhrcy idhyrc idhycr idhcyr idhcry idcrhy idcryh idchry idchyr idcyhr idcyrh
irdyhc irdych irdhyc irdhcy irdchy irdcyh irydhc irydch iryhdc iryhcd irychd
irycdh irhydc irhycd irhdyc irhdcy irhcdy irhcyd ircyhd ircydh irchyd irchdy
ircdhy ircdyh ihdryc ihdrcy ihdyrc ihdycr ihdcyr ihdcry ihrdyc ihrdcy ihrydc
ihrycd ihrcyd ihrcdy ihyrdc ihyrcd ihydrc ihydcr ihycdr ihycrd ihcryd ihcrdy
ihcyrd ihcydr ihcdyr ihcdry icdrhy icdryh icdhry icdhyr icdyhr icdyrh icrdhy
icrdyh icrhdy icrhyd icryhd icrydh ichrdy ichryd ichdry ichdyr ichydr ichyrd
icyrhd icyrdh icyhrd icyhdr icydhr icydrh cydrih cydrhi cydirh cydihr cydhir
cydhri cyrdih cyrdhi cyridh cyrihd cyrhid cyrhdi cyirdh cyirhd cyidrh cyidhr
cyihdr cyihrd cyhrid cyhrdi cyhird cyhidr cyhdir cyhdri cdyrih cdyrhi cdyirh
cdyihr cdyhir cdyhri cdryih cdryhi cdriyh cdrihy cdrhiy cdrhyi cdiryh cdirhy
cdiyrh cdiyhr cdihyr cdihry cdhriy cdhryi cdhiry cdhiyr cdhyir cdhyri crdyih
crdyhi crdiyh crdihy crdhiy crdhyi crydih crydhi cryidh cryihd cryhid cryhdi
criydh criyhd cridyh cridhy crihdy crihyd crhyid crhydi crhiyd crhidy crhdiy
crhdyi cidryh cidrhy cidyrh cidyhr cidhyr cidhry cirdyh cirdhy cirydh ciryhd
cirhyd cirhdy ciyrdh ciyrhd ciydrh ciydhr ciyhdr ciyhrd cihryd cihrdy cihyrd
cihydr cihdyr cihdry chdriy chdryi chdiry chdiyr chdyir chdyri chrdiy chrdyi
chridy chriyd chryid chrydi chirdy chiryd chidry chidyr chiydr chiyrd chyrid
chyrdi chyird chyidr chydir chydri

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

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