The numbers in each columns should have both tens digits and ones digits which differ from each other not more than 5. Then, for each received table, one should check numbers in all its columns. The created tables have numbers of columns equal to the currently analyzed lengths of the secret key. For each of the numbers, one should write the ciphertext, breaking lines after the amount of characters equal to that number. It may be achieved by trying some possible key lengths for probable values (for example from 4 to 15 characters). The first step during breaking the Nihilist cipher is discovering a length of the secret key. It makes the analyzing of the ciphertext much more easier. It happens when the corresponding letters of the plaintext and the secret key are located in the last (fifth) row of the table (so the addends are bigger that 50). During analyzing frequencies of characters in the ciphertext, one should check two-digit numbers.ĭuring encryption using the Nihilist algorithm, the ordinary addition is used (without modulo operation), so the ciphertext may contain three-digit numbers.
![letter number code decoder letter number code decoder](https://inspirationlaboratories.com/wp-content/uploads/2016/02/number-grid-cypher.jpg)
Therefore, one can use similar methods for its analysis and breaking. The Nihilist cipher is quite similar to the Vigenère cipher. He receives the plaintext numbers, which can be changed into letters using the same table as the sender used for encryption. The recipient, which knows the secret key, subtracts the secret key numbers from the ciphertext numbers.
![letter number code decoder letter number code decoder](https://d1nr5wevwcuzuv.cloudfront.net/product_photos/33744195/Decoder_20Ring_20Pic3_original.jpg)
The ciphertext is created by adding the plaintext numbers to the secret key numbers: 42 The plaintext and the secret encrypting key should be written in two rows, one under another: aĪfter replacing letters by numbers, the rows have the following form: 11 The created ciphertext can contain a sequence of numbers or the received numbers can be changed into letters using the same table and the inverse transform.įor example, the steps during encrypting of a sentence Acta est fabula using a secret keyword Vivere and the Polybius square defined above, are presented below. The results can be two-digit or three-digit numbers. Both the secret key (used for creating the table) and the secret key (used for encrypting all messages) must be shared between the communicating parties.ĭuring encryption one should add one by one all the numbers created from plaintext letters to the numbers created from the secret key's letters. The secret key is used during encryption of the whole communication. The secret key is usually different than the secret word used for create the table in the previous step. Usually the parties use an alphabetical order.īoth rows and columns of the table are numbered from 1 to 5.įor example, if a full name of the tsar Alexander II killed by Nihilists (Aleksandr II Nikolaevich) is used as the secret word, then the table can be written as below:Įach letter of the secret key and each letter of a given message is changed into a two-digit number, determined by digits of rows and columns. The rest of empty cells are filled with the rest of letters, which aren't contained by the secret word. However, the parties can agree to the different order. Usually the letters are written starting from the top leftmost cell and going to the right, row by row. To determine the order of letters, one should remove duplicate letters of the secret word and then enter the rest letters into the table. It has 5 rows and 5 columns and it is filled with all Latin letters (there are 26 Latin letters, so usually the letters i and j are treated as one character).Īn order of letters in the table depends on a secret word which is shared by the two communicating parties.
![letter number code decoder letter number code decoder](https://www.101computing.net/wp/wp-content/uploads/Morse_code.png)
![letter number code decoder letter number code decoder](https://morsedecoder.com/dist/images/morse-code-chart-touch.jpg)
AlgorithmĪn algorithm of the Nihilist cipher uses a matrix called a Polybius square. One of ciphers which belongs to the Nihilist family of ciphers is the VIC cipher. The original algorithm was not very strong but there are some modifications which provide much better security. They killed the tsar Alexander II in the successful assassination in 1881. The cipher is named after the Nihilist movement, who fought against czarism in Russia and attacked czarism's officials in the nineteenth century. Nihilist Cipher Polyalphabetic Substitution Cipherįirst used in the eighties of the nineteenth century in Russia by Nihilist organizations.