easy to crack the longer the length of ciphertext.
Vigenere encryption algorithm use the defined square
matrix and the custom key to encrypt the plaintext message. The normal Vigenere square matrix based on twenty six capital letters, followed by cycle changing the order, composed 26 × 26 square matrix. In order to improve the complexity of this algorithm, while improving the performance of confidentiality, In this paper, on the basis of twenty-six Capital letters, insert ten Arabic numbers into the sequence of letters of the alphabet, with turn loop arranged in a certain order, and ultimately construct the improved Vigenere square of 36 × 36.