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crc code RRS feed

  • Question

  • how to read a part of memory that access databse  is running and calculate crc for it to prevent debuger from putting breakpoint and resource the code.with some code example.crc code for prevent copying using usb lock and activex .

    microsoft

    Monday, January 16, 2017 1:36 PM

All replies

  • Hi,

    Not sure I understand your question but if you're trying to prevent someone from stealing your program, then you might want to focus your efforts elsewhere than trying to prevent them from making a copy of your application file.

    There are a lot of tutorials on how to "secure" an Access application, but none of them will prevent anyone from copying the file itself. The intent, instead, is to prevent the thief from "using" the copied file.

    Just my 2 cents...

    Monday, January 16, 2017 3:01 PM
  • Hi majzad,

    Here I think you are talking about Cyclic Redundancy Check.

    you had mentioned that ,"you want to prevent debuger from putting breakpoint and resource the code".

    so it's like you want to secure your code and don't want to access it by anyone.

    (1) you can try to put the password on your code. so nobody can access it.

    for that go to VBE.

    then go to "Tools" menu. then select "<Database Name> properties".

    then select "Protection" Tab and set the password.

    (2) other method , in case you want to share your database with anyone. then you can provide the compiled version of your db.

    (3) if you don't want that someone copy your database and use it. then you can create "AutoExec" macro. it will run when you open the database.

    so at this time you can check the location of your db and current logged in user.

    if it not match then you can close your database from code. so no any unauthorized person will able to use that.

    Regards

    Deepak


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    Tuesday, January 17, 2017 1:55 AM
    Moderator
  • in this case an authorized person could copy and distribute program.could not he?

    microsoft

    Tuesday, January 17, 2017 7:34 AM
  • in this case an authorized person could copy and distribute program.could not he?

    microsoft

    Hi,

    Anyone, authorized or not, "can" copy your file. There's really not much you can do about it. However, what you can control is if the person with a copy of your file can run it or not.

    Are you planning to sell your program?

    Tuesday, January 17, 2017 7:31 PM
  • Hey Deepak, re #3, would not anyone be able to hold down the Shift key and prevent the AutoExec macro from running?

    IMHO the first question to ask is "What exactly are you trying to achieve?" Security has many faces and it's an advanced topic.


    -Tom. Microsoft Access MVP

    Wednesday, January 18, 2017 5:07 AM
  • yes.but i am not using web base program to check if an especial username and password with two diffrent ip are online and close program.i want to sell it on cd for example.and use usb lock .although it is expensive as well.

    microsoft

    Wednesday, January 18, 2017 7:11 AM
  • yes.but i am not using web base program to check if an especial username and password with two diffrent ip are online and close program.i want to sell it on cd for example.and use usb lock .although it is expensive as well.

    microsoft

    Hi,

    I'm not sure how USB lock can protect a CD. In any case, you need to stop thinking about preventing users or anyone from copying your program. Instead, concentrate on how the program will only run if it is a legitimate copy.

    Just my 2 cents...

    Wednesday, January 18, 2017 4:42 PM
  • Hi majzad,

    (1) you had mentioned that,"but i am not using web base program to check if an especial username and password with two diffrent ip are online and close program."

    I also did not mentioned about "Web based program". I was talking about MS Access Application.

    (2) other thing you had mentioned that,"i want to sell it on cd for example.and use usb lock .although it is expensive as well."

    you can try to "VB6 Software Protection and keygen". (Third Party Code)

    This is software “lock” module placed on Visual Basic 6.0 program by the developer to prevent the program from being copied or distributed without approval or authorization. The required Serial Code is different for every computer that the program runs in. The Serial Code has five sets of codes with each set having 5 characters i.e. ABCDE-FGHIJ-KLMNO-PQRST-UVWXY. Also packaged is its Keygen and a Readme file that will help you understand the coding.

    below is the part of code.

    Frm_DataEntry - 1 
    '************************************************************************************************** ** '*  Author:             Masika .S. Elvas                                                            * '*  Gender:             Male                                                                        * '*  Postal Address:     P.O Box 137, BUNGOMA 50200, KENYA                                           * '*  Phone No:           (254) 724 688 172 / (254) 751 041 184                                       * '*  E-mail Address:     maselv_e@yahoo.co.uk / masika_elvas@programmer.net / masika_elvas@live.com  * '*  Location            BUNGOMA, KENYA                                                              * '************************************************************************************************** **
    Option Explicit
    Public strFilter$, strDefault$ Public mMax&, mMin&, mTrials&, mDialogAction Public IsPassword, mIsNumeric, mIsDecimal, ConfirmClosure As Boolean
    Private mCancelled As Boolean
    Private Sub CmdBrowse_Click()        With Dlg                .Flags = &H4 'Hide Read-Only checkbox                'Set Dialog to only show the specified Files.        'If no file type has been specified then show all the files        .Filter = VBA.IIf(VBA.Trim$(strFilter) = VBA.vbNullString, "All Files (*.*)|*.*", strFilter )                '0 No Action.        '1 Displays Open dialog box.        '2 Displays Save As dialog box.        '3 Displays Color dialog box.        '4 Displays Font dialog box.        '5 Displays Printer dialog box.        If mDialogAction + &H1 = &H2 Then .FileName = txtEntry.Tag        .Action = mDialogAction + &H1 'Display the CommonDialog control's defined dialog box.                If mDialogAction + &H1 = &H2 Then txtEntry.Text = .FileName: Call cmdOK_Click            End With    End Sub
    
    

    Reference:

    VB6 Software Protection and Keygen

    Download Code

    Disclaimer: This response contains a reference to a third party World Wide Web site. Microsoft is providing this information as a convenience to you. Microsoft does not control these sites and has not tested any software or information found on these sites; therefore, Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. There are inherent dangers in the use of any software found on the Internet, and Microsoft cautions you to make sure that you completely understand the risk before retrieving any software from the Internet.

    Regards

    Deepak


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    • Marked as answer by majzad Thursday, January 19, 2017 7:03 AM
    • Unmarked as answer by majzad Friday, January 20, 2017 6:54 AM
    Thursday, January 19, 2017 1:09 AM
    Moderator
  • thanks.i will test how it works.

    microsoft

    Thursday, January 19, 2017 7:01 AM
  • thanks.theDBguy.but any authorized users can distribute the database with their user and pass in the authorization table.cant they?

    microsoft



    • Edited by majzad Saturday, January 21, 2017 6:56 AM
    Thursday, January 19, 2017 7:03 AM
  • thanks Deepack.but is it work with vba in access or it is just for vb6?

    microsoft


    • Edited by majzad Friday, January 20, 2017 6:55 AM
    Thursday, January 19, 2017 7:04 AM
  • Hi majzad,

    it is a VBA Code and work with Access.

    you need to go through the documentation of the code to get the information regarding how to implement it with your code.

    whole code is available, you just need to combine with your code.

    now it's depend upon you how you make it work.

    Regards

    Deepak


    MSDN Community Support
    Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact MSDNFSF@microsoft.com.

    Friday, January 20, 2017 7:11 AM
    Moderator
  • thanks so much.

    microsoft

    Saturday, January 21, 2017 6:50 AM
  • Hi majzad,

    This thread is still open.

    if your issue is solved then please mark the suggestion as an answer that helped you to solved your issue.

    so that we can close this thread.

    if you had solved the issue by yourself then please try to share the suggestion on this thread and mark it as an answer. in future it will help others. 

    if your issue is still exist then let us know about that, so that we can again try to provide you a suggestion to solve the issue.

    Regards

    Deepak


    MSDN Community Support
    Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact MSDNFSF@microsoft.com.

    Wednesday, January 25, 2017 7:45 AM
    Moderator