What is Vigenere Cipher ?

-:Vigenere Cipher:- The Vigenère cipher is a type of polyalphabetic substitution cipher. It was considered unbreakable until 1863. To use the cipher a key text is generated that repeats for the length of the message to be encrypted. A combination of the plaintext letter and the corresponding key letter are used to locate the ciphertext value for the letter in a table. In the table, the row value would be the key letter, the plaintext would be located in the column. The location where the row and column intersect is the ciphertext letter to be used.