Securing trough files

hustelboy · 2011-08-04T12:31:12.000Z

On my program im using a login form. But to secure it more i want it to read a file. the file is a key that key is a usb with a file on it. I want it trough ftp that it reads the file on the usb and checks the file. then when its the right file you can login. I made something like that months ago but bad enough i lost all that files. Thanks in advice

check the files MD5 hash, and if its the right one,
form1.show?

Code:

' specify the path to a file and this routine will calculate your hash
    Public Function MD5CalcFile(ByVal filepath As String) As String

        ' open file (as read-only)
        Using reader As New System.IO.FileStream(filepath, IO.FileMode.Open, IO.FileAccess.Read)
            Using md5 As New System.Security.Cryptography.MD5CryptoServiceProvider
                ' hash contents of this stream
                Dim hash() As Byte = md5.ComputeHash(reader)
                ' return formatted hash
                Return ByteArrayToString(hash)
            End Using
        End Using
    End Function


    ' utility function to convert a byte array into a hex string
    Private Function ByteArrayToString(ByVal arrInput() As Byte) As String
        Dim sb As New System.Text.StringBuilder(arrInput.Length * 2)
        For i As Integer = 0 To arrInput.Length - 1
            sb.Append(arrInput(i).ToString("X2"))
        Next
        Return sb.ToString().ToLower
    End Function

maybe something like....

Code:

if MD5CalcFile(filepath) = "md5 of the check file" = true then
'logon script
else
msgbox("Key not found, please contact creator")
end if

Securing trough files

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