[VB.NET]SecureString較為安全的加密字串類別

April 29, 2010

Public Sub PrintSecureString(ByVal secureString As SecureString)
...
End Sub</pre></div>

Module Module1

Sub Main()
    Console.WriteLine("Please enter your password to be encrypted:")

    Dim password As SecureString = ReadPassword()

    Console.WriteLine()

    Console.WriteLine("Decripted password:")

    PrintPassword(password)
End Sub


Public Function ReadPassword() As SecureString

    Dim password As New SecureString()

    Dim nextKey As ConsoleKeyInfo = Console.ReadKey(True)

    While nextKey.Key &lt;&gt; ConsoleKey.Enter
        If nextKey.Key = ConsoleKey.Backspace Then
            If password.Length &gt; 0 Then
                password.RemoveAt(password.Length - 1)

                ' erase the last * as well
                Console.Write(nextKey.KeyChar)
                Console.Write(" ")
                Console.Write(nextKey.KeyChar)
            End If
        Else
            password.AppendChar(nextKey.KeyChar)
            Console.Write("*")
        End If

        nextKey = Console.ReadKey(True)
    End While

    password.MakeReadOnly()
    ' make the password read-only.

    ' return the encrypted password.

    Return password

End Function

Public Sub PrintPassword(ByVal password As SecureString)

    ' Uncrypt the password and get a reference to it...

    Dim bstr As IntPtr = Marshal.SecureStringToBSTR(password)


    Try
        ' Printing the uncrypted password...

        Console.WriteLine(Marshal.PtrToStringBSTR(bstr))

    Finally

        Marshal.ZeroFreeBSTR(bstr)

    End Try

End Sub

End Module

VB.NET