console program, simultaneous password & timer

I'm in a bit of a pickle here. I would like to edit one of my codes to have a password query with a timer. Basic outline of its function would be to state that the user has 30 seconds to input the correct password before the program states that the time has run out and restricts all access but does not end the program. I would like to see the timer state how many seconds is left after every 5 seconds, i.e 25.20.15.10.5.0. My problem is that I have no idea how to override console.readline command which you need for the password input.

Any ideas?

from MSDN documentation - Use the KeyAvailable property in conjunction with the ReadKey method

Hmm maybe I should've stated that I'm a total beginner at coding. I've been learning this for a few weeks, and basicly what I've got downloaded into my brain is basic if sentences, for sentences, while sentences and the most basic of statements and commands. Basicly I know the basics, but none of those fancy commands.

An example would help, one as simple as can be :)

I was intrigued by this so I thought I'd give it a bash. This would need a bit of refining to be truly usable, like giving the user the ability to reset the current password if they made a mistake, but it should give you the general idea.

vb.net Code:

Imports System.Threading
 
Module Module1
 
    Sub Main()
        Console.WriteLine("Please enter a valid password within 30 seconds.")
 
        Const VALID_PASSWORD As String = "Password"
        Dim currentPassword As String = String.Empty
 
        Dim warningInterval As TimeSpan = TimeSpan.FromSeconds(5)
        Dim timer As Stopwatch = Stopwatch.StartNew()
 
        Do
            Thread.Sleep(100)
 
            While Console.KeyAvailable
                currentPassword &= Console.ReadKey().KeyChar
            End While
 
            If currentPassword = VALID_PASSWORD Then
                Console.WriteLine()
                Console.WriteLine("Valid password entered.")
                Thread.Sleep(500)
                Exit Do
            ElseIf timer.Elapsed > warningInterval Then
                If warningInterval.TotalSeconds = 30 Then
                    Console.WriteLine()
                    Console.WriteLine("Time's up.")
                    Thread.Sleep(500)
                    Exit Do
                Else
                    Console.WriteLine()
                    Console.WriteLine((30 - warningInterval.TotalSeconds) & " seconds remaining.")
                    warningInterval = warningInterval.Add(TimeSpan.FromSeconds(5))
                End If
            End If
        Loop
    End Sub
 
End Module

If you don't understand it all, PLEASE read the MSDN documentation for the types and methods I've used before posting any questions.

Thanks! That was a great help. I understand it for the most part, and I modified it to fit on to my code and it works perfectly. You really helped me out of a bad jam there. Thank you.