tnt672397
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TRIAL VERSION
I created an application using VB6 and I want users to only have access to running the program for only 15 days (15-Day Free Trial). Currently, I set up a regDate in a database..so when the current date is greater than the regDate +15, program is no longer accessible. However, if someone changes the date in the Date/Time settings, they can outfool the regDate. Also, by re-installing the program...you can get another 15-days.
So what I need is
Method on giving users only 15 days of running my program.
(1) User cannot get more access from program by uninstalling/reinstalling it (after 15 days)
(2) User cannot affect the program by changing the Date/Time settings
Who Can Help Me?
So what I need is
Method on giving users only 15 days of running my program.
(1) User cannot get more access from program by uninstalling/reinstalling it (after 15 days)
(2) User cannot affect the program by changing the Date/Time settings
Who Can Help Me?
ASKER
Ok sounds good, how do I create a text file in the winfile.dll?
Using VB6
Using VB6
Hai,
I've given sample to create a new file alone... just change the code to do encryption and overwrite it with current date.
Private Declare Function GetSystemDirectory Lib "kernel32" Alias "GetSystemDirectoryA" (ByVal lpBuffer As String, ByVal nSize As Long) As Long
Private Sub Command1_Click()
Dim FileNum As Variant
FileNum = FreeFile
Open SystemDirectory() & "\WinFile.dll" For Append As #FileNum
Print #FileNum, "InstalledDate = " & Now
Print #FileNum, "CurrentDate = " & Now
Close #FileNum
End Sub
Function SystemDirectory() As String
Dim strSystemDirectory As String * 260
GetSystemDirectory strSystemDirectory, 260
SystemDirectory = TrimNulls(strSystemDirecto
End Function
Private Function TrimNulls(ByVal strIn As String) As String
Dim intPos As Integer
intPos = InStr(strIn, vbNullChar)
If intPos = 0 Then
' No nulls in the string, just return it as is
TrimNulls = strIn
Else
If intPos = 1 Then
' If the null character is at the first position, the
' entire string is a null string, so return a zero-length string
TrimNulls = ""
Else
' Not at the first position, so return the contents up
' to the occurrence of the null character
TrimNulls = Left$(strIn, intPos - 1)
End If
End If
End Function
Bye
Ajai
I've given sample to create a new file alone... just change the code to do encryption and overwrite it with current date.
Private Declare Function GetSystemDirectory Lib "kernel32" Alias "GetSystemDirectoryA" (ByVal lpBuffer As String, ByVal nSize As Long) As Long
Private Sub Command1_Click()
Dim FileNum As Variant
FileNum = FreeFile
Open SystemDirectory() & "\WinFile.dll" For Append As #FileNum
Print #FileNum, "InstalledDate = " & Now
Print #FileNum, "CurrentDate = " & Now
Close #FileNum
End Sub
Function SystemDirectory() As String
Dim strSystemDirectory As String * 260
GetSystemDirectory strSystemDirectory, 260
SystemDirectory = TrimNulls(strSystemDirecto
End Function
Private Function TrimNulls(ByVal strIn As String) As String
Dim intPos As Integer
intPos = InStr(strIn, vbNullChar)
If intPos = 0 Then
' No nulls in the string, just return it as is
TrimNulls = strIn
Else
If intPos = 1 Then
' If the null character is at the first position, the
' entire string is a null string, so return a zero-length string
TrimNulls = ""
Else
' Not at the first position, so return the contents up
' to the occurrence of the null character
TrimNulls = Left$(strIn, intPos - 1)
End If
End If
End Function
Bye
Ajai
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Try http://www.activelock.com/
They have an activex control for this. It may help you. Avoid storing information in the registry where you can, as its easily retrieved.
They have an activex control for this. It may help you. Avoid storing information in the registry where you can, as its easily retrieved.
1. Instead of saving it on database use registry or encrypted text file inside system folder named something like "winfile.dll".
2. Add installed date on file/registry
3. Add an key of current date and update it day by day when the application starts. Check current date with this date so that the user can't change the system date if the system date is below this date inform the user that he had changed the date to some other date so that the app wont start and ask him to reset it to original date.
4. find the diffrence between current date and installed date, if it's above 15 days inform user that it's expired.
5. while installing your application check whether the reigstry/file exist already if it's dont overwite it.
Bye
Ajai