Vatsyayana cipher

The Vatsyayana cipher is a simple substitution cipher where the 26 letters of the alphabet are organised into 13 pairs of characters. These pairs are then used to encrypt the text by direct substitution of the letters in the pairs.

With the above key, all “A” letters in the plain text will be encoded to an “E” whereas all letters “E” will be replaced with an “A”.

This type of cipher is a form of symmetric encryption as the same key can be used to both encrypt and decrypt a message.

You can generate your own encryption keys and encrypt your own messages using our online mono-alphabetic substitution engine:

Frequency Analysis

One approach used to help decrypt a Vatsyayana substitution cipher is to use a frequency analysis based on counting the number of occurrence of each letter to help identify the most recurrent letters. (e.g. In the English language, letters E, T, A and O).