Shift Cipher

Time:2021-1-18

Shift Cipher

The Shift Cipher itself is very simple, that is, each letter in plaintext moves a fixed length position in the alphabet.

Suppose x, y, K, Z_ If {26}, then\\

From the previous discussion on replacement ciphers, it is not difficult to come to the conclusion that shift ciphers are not secure at all. There are only two ways to attack Shift Cipher

  1. Since there are only 26 different keys (shift length), the attacker can easily use brute force attack to try to crack the given ciphertext with all possible 26 letters. If the plaintext is readable, we have found the key.
  2. As with replacement passwords, letter frequency analysis can also be used.

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