Masked password + MD5 encryption

Hello, I'm making a console application with a login. The system I have now is extremely basic and very redundant. I would like the password to be masked as you type it in "*****" for example and If possible I would like to encrypt the password with md5. Can someone let me know how to/give me the code to do it.

This is my current login system:

Code:

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Sub LogIn()
        'A log in system to prevent unwanted users from acsessing the system
        Console.Write("Username: ")
        Dim username As String = Console.ReadLine.ToLower
        If username = "sian" Then
            loginPassword()
            'If the username is correct it goes on to the main screen.
        Else
            'If the username is wrong it loops back into the log in
            Console.Clear()
            LogIn()
        End If
        End
    End Sub

    'If the password is correct it goes on to ask for the password
    Sub loginPassword()
        Console.Write("Password: ")
        Dim Password As String = Console.ReadLine.ToLower
        If Password = "password" Then
            Console.Clear()
            options()
            'If the password is correct it leads into the options
        Else
            'If the password is wrong it loops back into the log in
            Console.Clear()
            LogIn()
        End If
        End
    End Sub

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For example, it could be:

Code:

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Module Module1

    Private _cyphredPassword As String = String.Empty
    'correct pwd is "sian" (without the quotes)
    Private Const correctPwd As String = "5OoLtL2yrc0/2nBmVfY5YQ=="
    Sub Main()

        Dim sb As New System.Text.StringBuilder
        sb.AppendLine()

        If LogIn() Then

            sb.AppendLine("You succesfully logged in")

        Else
            sb.AppendLine("Invalid userName or Password")
        End If

        sb.AppendLine("Press any key to quit")
        Console.WriteLine(sb.ToString)
        Console.ReadKey()
    End Sub


    Private Function LogIn() As Boolean
        Dim ret As Boolean = False

        'A log in system to prevent unwanted users from acsessing the system
        Console.Write("Username: ")
        Dim username As String = Console.ReadLine.ToLower
        If username = "sian" Then
            ret = loginPassword()
            'If the username is correct it goes on to the main screen.
        Else
            'If the username is wrong it loops back into the log in
            Console.Clear()
            ret = LogIn()
        End If
        Return ret
    End Function

    'If the password is correct it goes on to ask for the password
    Private Function loginPassword() As Boolean
        Dim ret As Boolean
        Dim plainPassowrd As String = String.Empty
        Console.Write("Password (press enter when you are done) : ")
        Do
            Dim keyPressed As ConsoleKeyInfo = Console.ReadKey(True)
            Select Case keyPressed.Key
                Case ConsoleKey.A To ConsoleKey.Z
                    Console.Write("*")
                    plainPassowrd += keyPressed.KeyChar
                Case ConsoleKey.Enter

                    Exit Do
            End Select



        Loop
        If Not String.IsNullOrEmpty(plainPassowrd.Trim) Then
            _cyphredPassword = EncryptPwd(plainPassowrd)
            If _cyphredPassword.Equals(correctPwd, System.StringComparison.Ordinal) Then
                ret = True
            End If
        End If

        Return ret
    End Function

    Private Function EncryptPwd(plainPassowrd As String) As String
        '
        'this routine is from: http://www(dot)a1vbcode(dot)com/vbtip-149(dot)asp
        '
        '(substitute "(dot)" with "." if you want to go there. I posted as I try to give credits to those who deserve)
        '
        'Create an encoding object to ensure the encoding standard for the source text
        Dim Ue As New System.Text.UnicodeEncoding()
        'Retrieve a byte array based on the source text
        Dim ByteSourceText() As Byte = Ue.GetBytes(plainPassowrd)
        'Instantiate an MD5 Provider object
        Dim Md5 As New System.Security.Cryptography.MD5CryptoServiceProvider()
        'Compute the hash value from the source
        Dim ByteHash() As Byte = Md5.ComputeHash(ByteSourceText)
        'And convert it to String format for return
        Return Convert.ToBase64String(ByteHash)

    End Function

End Module

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