如何使文件只有在保存时才能被用户读取+VB.net/C#

Question

如何使文件仅在保存到磁盘（例如C驱动器）时才可由用户读取？

Answer 1

如果数据源于应用程序，并且仅针对同一台Windows机器上的当前用户，则

// using System.Security.Cryptography;
var path = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData) + 
    @"/user data that only a program run by this user can read.dat";
Console.WriteLine(path);
var entropy = Encoding.UTF8.GetBytes("See http://security.stackexchange.com/a/58121");

var data = Encoding.UTF8.GetBytes(
    @"Data to be stored in a way that only programs that run under 
    this account can decrypt but nobody's eyes can understand. But 
    if an admin forces a password change, it's irretrievable 
    (see http://stackoverflow.com/a/4755929/2226988).");
File.WriteAllBytes(path, ProtectedData.Protect(
    data, 
    entropy, 
    DataProtectionScope.CurrentUser));

var readBack = ProtectedData.Unprotect(
    File.ReadAllBytes(path), 
    entropy, 
    DataProtectionScope.CurrentUser);
Console.WriteLine(Encoding.UTF8.GetString(readBack));