Creating Secure Trial Versions for .NET Applications - A Tutorial

Imports System.Diagnostics

Public Class ClockManipulationDetector
    Public Shared Function DetectClockManipulation(thresholdTime As DateTime) As Boolean
        Dim adjustedThresholdTime As DateTime = New DateTime(thresholdTime.Year, thresholdTime.Month, thresholdTime.Day, 23, 59, 59)

        Dim eventLog As EventLog = New System.Diagnostics.EventLog("system")

        For Each entry As EventLogEntry In eventLog.Entries
            If (entry.TimeWritten > adjustedThresholdTime) Then
                Return True
            End If
        Next

        Return False

    End Function
End Class