Vigenere Cipher is a kind of stream cipher that can be easily broken. If we could hide the cycles and the key length, the vigenere cipher could be so useful. By adding eight random bits for every byte we can make this cipher, protected. We can diffuse the padded random bits between the plaintext bits by using a function that can increase the length of the cipher text in order to protect the cipher. Any how the security of the cipher system is related to the key management processes.