## How do I fix my Adfgvx?

To decrypt a message recieved using the ADFGVX Cipher we must first undo the Columnar Transposition by writing the ciphertext in the grid in the right way. Then we read off the rows (with the keyword correctly ordered) and finally convert the pairs of letters back to plaintext using the Mixed Square.

**How many possible keys are there for the Adfgvx cipher?**

In June 1918, an additional letter, V , was added to the cipher. That expanded the grid to 6 × 6, allowing 36 characters to be used.

**How do you read Polybius?**

How to decrypt Polybius cipher? Polybius decryption requires to know the grid and consists in a substitution of couples of coordinates by the corresponding letter in the grid. Split the message in bigrams, couples of numbers that are the coordinates of each plain text letter.

### What was used by the Nihilist?

In the history of cryptography, the Nihilist cipher is a manually operated symmetric encryption cipher, originally used by Russian Nihilists in the 1880s to organize terrorism against the tsarist regime.

**What is the formula for decryption in Hill cipher?**

Decryption. Decrypting with the Hill cipher is built on the following operation: D(K, C) = (K-1 *C) mod 26 Where K is our key matrix and C is the ciphertext in vector form. Matrix multiplying the inverse of the key matrix with the ciphertext produces the decrypted plaintext.

**What is homophonic cipher?**

The Homophonic Substitution cipher is a substitution cipher in which single plaintext letters can be replaced by any of several different ciphertext letters. As we allow more and more possible alternatives for each letter, the resulting cipher can become very secure.

## When was the Four Square cipher used?

1902

Four square cipher The four-square cipher uses four squares, and where we take pairs of letters and, using the first and last square, we find the letters that are bounded by the two letters (like Playfair). It was invented by Félix Delastelle and published in 1902. It uses four 5×5 matrices arranged in a square.

**What is Caesar box?**

Caesar Box is a transposition cipher used in the Roman Empire, in which letters of the message are written in lines in a square (or a rectangle) and then, read by column.

**Who created the nihilist Cypher?**

2.2 Nihilist Cipher Nihilist cipher was first developed by the Russian Nihilists, namely Russians who supported the way of violence to achieve the desired political change, in this case overthrowing the power of Tsar Alexander II in Russia.

### How many combinations of keys can be constructed from a 72 ciphertext stream cipher?

9. How many combinations of keys can be constructed from a 72 ciphertext stream cipher? Explanation: For stream cipher, if there are n ciphertexts then there are n*(n−1)/2 combination of keys to be made. = 2556.