Vigenere Cipher

Vigenere Cipher is a tool developed after an old cryptographic system invented in the 16th century. While it is basically obsolete nowadays and offers little security given the current standards, it can still constitute a great learning experience.

Similarly to the original system, the console tool allows you to encrypt and decrypt messages and files using the original form of the cipher. A great example of how this old cryptographic mechanism works is saving a file or document with a password. Relying on XOR, the tool focuses on the modified bytes, instead of the letters and has been used to solve GeoCaches.

The interface is minimalistic and console-like, but it doesn’t require you know commands to operate it. In fact, all you need to get started is a ciphertext and a key to start. Both of them are analyzed and the app removes the non-alphabetical characters and capitalizes all remaining letters. Afterwards a Caesar shift is applied to each character.

The developer mentions that it is possible to solve the cipher even without the key, but under certain conditions when the text is longer than the key and the language is known. Simply put, you need a plaintext in English longer than 255 words, which is the maximum length of the key.