Tool to decrypt/encrypt with modulo. Modulo calculations applied on numbers can make possible ciphering using the calculated values.

Modulo Cipher - dCode

Tag(s) : Homophonic Substitution Cipher

dCode is free and its tools are a valuable help in games, maths, geocaching, puzzles and problems to solve every day!

A suggestion ? a feedback ? a bug ? an idea ? *Write to dCode*!

**Modulo Cipher** Encryption uses modular arithmetics and a sequence of numbers, characters must be converted into numbers, e.g. `A=1`, `B=2`, ... `Z=26`, but any numeric conversion (like the ASCII table) is fine.

__Example:__ To crypt `DCODE` with the modulo `26`, convert the text to numbers `4,3,15,4,5`.

For each number to encrypt, calculate a random number which value is equal to the number to crypt.

__Example:__ For $ 4 $, take $ 654 $, as $ 654 \equiv 4 \ mod 26 $

For $ 3 $, take $ 965 $, as $ 965 \equiv 3 \ mod 26 $.

The encrypted message is `654,965,561,732,941` (many other cipher message are possible)

Decryption requires to know the value of the Modulo and to know the series of number to decrypt.

__Example:__ The encrypted message is `654,965,561,732,941`with the modulo `26`.

For each number `N`, calculate the value of the remainder in the euclidean division of `N` by the modulo to get the plain number.

__Example:__ The plain text is `4,3,15,4,5`, that can be translate into `DCODE` with A=1, B=2, ...

The ciphered message is constituted of somehow large random numbers.

The Affine cipher use modulo in the calculation $ C = a \times P + b \ mod 26 $

dCode retains ownership of the online "Modulo Cipher" source code. Except explicit open source licence (indicated CC / Creative Commons / free), the "Modulo Cipher" algorithm, the applet or snippet (converter, solver, encryption / decryption, encoding / decoding, ciphering / deciphering, translator), or the "Modulo Cipher" functions (calculate, convert, solve, decrypt / encrypt, decipher / cipher, decode / encode, translate) written in any informatic language (Python, Java, PHP, C#, Javascript, Matlab, etc.) and all data download, script, copy-paste, or API access for "Modulo Cipher" are not public, same for offline use on PC, tablet, iPhone or Android ! Remainder : dCode is free to use.

Please, check our dCode Discord community for help requests!

NB: for encrypted messages, test our automatic cipher identifier!

modulo,cipher,remainder,division,calculator,modular,euclide,euclidean,mod,modulus

Source : https://www.dcode.fr/modulo-cipher

© 2021 dCode — The ultimate 'toolkit' to solve every games / riddles / geocaching / CTF.

Feedback

▲
Thanks to your feedback and relevant comments, dCode has developed the best 'Modulo Cipher' tool, so feel free to write! Thank you!