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Certificate expired

05 Oct 2021 18:12 #10257 by alenjursic1997
Replied by alenjursic1997 on topic Certificate expired
Thank you for quick response.

Really appreciate your help.
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05 Oct 2021 17:23 #10256 by admin
Replied by admin on topic Certificate expired
currently (as of version 2021.2), the validity period of auto-generated certificates cannot be changed in QuickOPC.

You can generate a certificate with longer validity period manually. See and . If you use the same Subject Name, and place the certificate files it into the proper directories, it will be found by QuickOPC application and used.

QuickOPC applications issue a new auto-generated certificate when no instance certificate found. You can create a recurring job on the computer (e.g. using Task Scheduler) to simply delete the certificate files with desired period, and QuickOPC application will renew its certificate - as you suggested. Note, however, that this does not resolve the problem on the server you are connecting to - because it will most likely not trust the renewed certificate.

Certificate validity should be set based on security evaluation. One of the concerns is that the computing power of your model attackers should not be able to crack the certificate key during the certificate validity period. Given the current encryption algorithms and key sizes used, AFAIK 100 years is too long, as it would be possible to crack it sooner, using commercially available tools.

Best regards
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04 Oct 2021 19:12 #10250 by alenjursic1997

I have a problem with auto generated QuickOPC client certificates. They are valid for 1 year and after I deploy my solution to customer's machine, I don't want to interfere with the system anymore. Currently after 1 year, my programs start returning exception saying that certificate has expired. I know that deleting current certificate solves my problem, but just for next 1 year.
  • Is it possible that QuickOPC generates cerificate that is valid for longer period (etc. 100 years)?
  • Are there any solutions to automatize this problem? (e.g: QuickOPC client could auto remove certificate after expiration or something like that).

Another idea I have is that I set scheduled Windows task, to delete current certificate each year, but this can bring another problems.

Best regards, Alen

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