Vigenere

代码说明：

   实现维吉尼亚密码，用键盘接收明文和密钥，屏幕打印密文和解密后的明文。 可以实现：大小写敏感，明文小写则密文大写，明文大写则密文小写输出，注意输入的健壮性控制，明文字符超出字符集后保留原文(Virginia to achieve the password, use the keyboard to receive the plaintext and the key, the screen printing ciphertext and the decrypted plaintext. Can be achieved: case sensitive, then the ciphertext plaintext lowercase uppercase, lowercase plaintext ciphertext output is capital, pay attention to the robustness of the control input, plaintext characters out retain the original character set)