/// <summary>
/// This function restores user credentials using the Windows Data Protection API
/// </summary>
/// <param name="userName"></param>
/// <param name="password"></param>
public static void RestorePerUserCredentials(out string userName, out SecureString password, string fileName, string keyName)
{
userName = null;
password = null;
// Read the encryption key from the registry
var sunKey = Registry.CurrentUser.OpenSubKey("Software\\SystemsUnitedNavy");
if (sunKey == null) // If no encryption key exists, return no credentials as we can't decrypt the credentials files in this case
{
return;
}
var entropy = sunKey.GetValue(keyName);
var decryptedData = ProtectedData.Unprotect(File.ReadAllBytes(fileName), (byte[])entropy, DataProtectionScope.CurrentUser);
string credentials = ByteArrayToString(decryptedData);
var splitted = credentials.Split(new string[] { ";#" }, StringSplitOptions.RemoveEmptyEntries);
if (splitted.Length == 2)
{
userName = splitted[0];
password = SecureStringUtility.StringToSecureString(splitted[1]);
}
}
/// <summary>
/// This function stores user credentials using the Windows Data Protection API
/// </summary>
/// <param name="userName"></param>
/// <param name="password"></param>
public static void StorePerUserCredentials(string userName, SecureString password, string fileName, string keyName)
{
// Generate additional entropy (will be used as the Initialization vector)
// This is basically the (2048-bit) encryption key used to encrypt the credentials
// The encryption key changes everytime the credentials get stored for increased security (everytime someone logs in with "Remember Me" ticked)
byte[] entropy = new byte[256];
using (RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider())
{
rng.GetBytes(entropy);
}
var currentUserRegistry = Registry.CurrentUser.OpenSubKey("Software\\SystemsUnitedNavy", true);
if (currentUserRegistry == null)
{
currentUserRegistry = Registry.CurrentUser.CreateSubKey("Software\\SystemsUnitedNavy", RegistryKeyPermissionCheck.Default);
}
currentUserRegistry.SetValue(keyName, entropy);
var data = ProtectedData.Protect(StringToByteArray(string.Format("{0};#{1}",
userName, SecureStringUtility.SecureStringToString(password))),
entropy,
DataProtectionScope.CurrentUser);
File.WriteAllBytes(fileName, data);
}