string转为byte[ ]类型
string plainText="abcdef";
//方法一
byte[] keyBytes = Encoding.UTF8.GetBytes(plainText);
//方法二
byte[] keyBytes1 = Hex.Decode(plainText);
byte[ ]转为string类型
byte[] keyBytes;
//方法一
string cipherText = Encoding.UTF8.GetString(Hex.Encode(keyBytes));
//方法二
string cipherText1 =Convert.ToBase64String(keyBytes);