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Custom file type

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  • E Etienne_123

    Which encryption algorithm would you recommend though? There are numerous included in .NET. The one I came across that works fine is "RijndaelManaged".

    OriginalGriffO Offline
    OriginalGriffO Offline
    OriginalGriff
    wrote on last edited by
    #11

    For your situation I wouldn't go for anything too complex - All you want is something that bollixes up the simple user from getting his high-res pics for free, I assume? Follow this[^] and you won't go too far wrong - it's pretty easy to follow, but without your key it's pretty much unbreakable. It won't stop the FBI or the mafia, but then I hope your pictures wouldn't interest either! :laugh:

    Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.

    "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
    "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt

    E 1 Reply Last reply
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    • E Etienne_123

      Hi I have a friend who's a photographer and he's looking for a way to burn DVDs for his customers with the photos on. He wants to include both low resolution and high resolution photos on the disc, but he doesn't want his customers to be able to access the high res photos. They must bring the disc to him if they want any photos printed. What I suggested to him was to create an application that will allow him to save the photos in a different file format, and only he must be able to open these photos with this application. I quickly fiddled with some code and saved an image in a different file format, but then of course one can still open these files by simply using the "Open With" dialog. I know there must be more to it than simply just saving it in a different file format. Maybe using some form of Serializer? Any help in the right direction would be appreciated.

      N Offline
      N Offline
      Not Active
      wrote on last edited by
      #12

      The best way to keep secrets is to not have any. If they must come to him to have images printed anyway, why even store them on the disc? Keeping them does put the onus on the photographer for storage but I'd be surprised if doesn't already have a backup plan. It also gives the option for a client to call/email an order and have them sent.


      I know the language. I've read a book. - _Madmatt

      E 1 Reply Last reply
      0
      • OriginalGriffO OriginalGriff

        For your situation I wouldn't go for anything too complex - All you want is something that bollixes up the simple user from getting his high-res pics for free, I assume? Follow this[^] and you won't go too far wrong - it's pretty easy to follow, but without your key it's pretty much unbreakable. It won't stop the FBI or the mafia, but then I hope your pictures wouldn't interest either! :laugh:

        Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.

        E Offline
        E Offline
        Etienne_123
        wrote on last edited by
        #13

        Yes you're completely right. While we're on the subject, would it be possible to compile all of these photos into one single encrypted package which can then only be opened by the application? That would be ideal, but if I have to store all the files separately then that's not a train smash either.

        OriginalGriffO 1 Reply Last reply
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        • N Not Active

          The best way to keep secrets is to not have any. If they must come to him to have images printed anyway, why even store them on the disc? Keeping them does put the onus on the photographer for storage but I'd be surprised if doesn't already have a backup plan. It also gives the option for a client to call/email an order and have them sent.


          I know the language. I've read a book. - _Madmatt

          E Offline
          E Offline
          Etienne_123
          wrote on last edited by
          #14

          I asked the same question :-D The only reason I can think of is that he does not want to keep backups of all his photos.

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          • L Luc Pattyn

            put the hi-res files inside a password-protected ZIP; or encrypt them. :)

            Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

            Please use <PRE> tags for code snippets, they preserve indentation, and improve readability.

            Y Offline
            Y Offline
            Yusuf
            wrote on last edited by
            #15

            Luc Pattyn wrote:

            a password-protected ZIP

            very easy to copy and crack :thumbsdown:

            Luc Pattyn wrote:

            encrypt them

            better alternative. :thumbsup:

            Yusuf May I help you?

            A 1 Reply Last reply
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            • E Etienne_123

              Hi I have a friend who's a photographer and he's looking for a way to burn DVDs for his customers with the photos on. He wants to include both low resolution and high resolution photos on the disc, but he doesn't want his customers to be able to access the high res photos. They must bring the disc to him if they want any photos printed. What I suggested to him was to create an application that will allow him to save the photos in a different file format, and only he must be able to open these photos with this application. I quickly fiddled with some code and saved an image in a different file format, but then of course one can still open these files by simply using the "Open With" dialog. I know there must be more to it than simply just saving it in a different file format. Maybe using some form of Serializer? Any help in the right direction would be appreciated.

              Y Offline
              Y Offline
              Yusuf
              wrote on last edited by
              #16

              Another Idea. Leave the hi-res images as hi-res so the customer can open them and see the difference. But put distinct watermark, so when printed it does not look good.

              Yusuf May I help you?

              1 Reply Last reply
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              • Y Yusuf

                Luc Pattyn wrote:

                a password-protected ZIP

                very easy to copy and crack :thumbsdown:

                Luc Pattyn wrote:

                encrypt them

                better alternative. :thumbsup:

                Yusuf May I help you?

                A Offline
                A Offline
                AspDotNetDev
                wrote on last edited by
                #17

                You do realize that password-protecting a ZIP file is a form of encryption, right?

                [Forum Guidelines]

                Y 1 Reply Last reply
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                • A AspDotNetDev

                  You do realize that password-protecting a ZIP file is a form of encryption, right?

                  [Forum Guidelines]

                  Y Offline
                  Y Offline
                  Yusuf
                  wrote on last edited by
                  #18

                  One of the weakest types of encryption, huh! :^)

                  Yusuf May I help you?

                  A 1 Reply Last reply
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                  • Y Yusuf

                    One of the weakest types of encryption, huh! :^)

                    Yusuf May I help you?

                    A Offline
                    A Offline
                    AspDotNetDev
                    wrote on last edited by
                    #19

                    I don't know, is 256-bit AES encryption weak?

                    [Forum Guidelines]

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                    • E Etienne_123

                      Yes you're completely right. While we're on the subject, would it be possible to compile all of these photos into one single encrypted package which can then only be opened by the application? That would be ideal, but if I have to store all the files separately then that's not a train smash either.

                      OriginalGriffO Offline
                      OriginalGriffO Offline
                      OriginalGriff
                      wrote on last edited by
                      #20

                      Yes - the encryption doesn't care what the content is. I would suggest either a simple directory structure, or just a length prefix/filename combination to each file so you can extract them from the decrypted stream.

                      Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.

                      "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
                      "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt

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