Présentation
À propos de cette application
La description d’origine est affichée : aucune version française n’a été conservée.
Caesar Cipher / Shift Cipher encryption technique based tool.
The basic concept of the Caesar Cipher is one of the encryption techniques that is said to have been used by Gaius Iulius Caesar (*July 100BC; †March 15th, 44BC) to protect message exchange among his military troops.
Caesar Cipher encryption is basically performed by monoalphabetic character substitution. Substitution is performed by applying a positional shift in a given alphabet. Reversing the shift by same amount of positions with same alphabet decrypts the ciphered text into plain text again. Such that the secret key in this symmetric cipher is represented by
<ul> <li>the number respresenting the amount of positions to shift, and</li> <li>the usage of the correct alphabet to be applied.</li></ul>
Compared to modern encryption techniques the Caesar Cipher is rated to be a weak encryption. Still it obviously has historical relevance and is popular since simple to understand.
A common attack to decrypt the cipher is to use a frequency analysis of the signs in use and compare the sign frequencies towards empirical frequencies of letters in an assumed or related target language, e.g. the assumption that the letter 'e' has characteristic high frequency in languages like English or German. Obviously such an statistical attack works better on huger amount of ciphered texts since the measured frequency spectrum gets closer towards the empirical spectrum for natural language.
The basic concept of the Caesar Cipher is one of the encryption techniques that is said to have been used by Gaius Iulius Caesar (*July 100BC; †March 15th, 44BC) to protect message exchange among his military troops.
Caesar Cipher encryption is basically performed by monoalphabetic character substitution. Substitution is performed by applying a positional shift in a given alphabet. Reversing the shift by same amount of positions with same alphabet decrypts the ciphered text into plain text again. Such that the secret key in this symmetric cipher is represented by
<ul> <li>the number respresenting the amount of positions to shift, and</li> <li>the usage of the correct alphabet to be applied.</li></ul>
Compared to modern encryption techniques the Caesar Cipher is rated to be a weak encryption. Still it obviously has historical relevance and is popular since simple to understand.
A common attack to decrypt the cipher is to use a frequency analysis of the signs in use and compare the sign frequencies towards empirical frequencies of letters in an assumed or related target language, e.g. the assumption that the letter 'e' has characteristic high frequency in languages like English or German. Obviously such an statistical attack works better on huger amount of ciphered texts since the measured frequency spectrum gets closer towards the empirical spectrum for natural language.