Read Only

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BobH
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Read Only

Post by BobH »

In Windows, it is my understanding that assigning the 'read only' property to a file means that it can not be changed. Is there a way to set a property so that the file can only be read but not changed or saved?
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HansV
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Re: Read Only

Post by HansV »

You could create a PDF file and protect it against editing and copying its contents. But
a) One can still make a screenshot and run that through OCR software to retrieve at least part of the text, and
b) If you search diligently, you'll find tools and services that claim to be able to unlock a protected PDF file.
Best wishes,
Hans

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BobH
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Re: Read Only

Post by BobH »

Thanks, Hans!

Still working on ways to protect intellectual property both physically and legally.
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Jay Freedman
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Re: Read Only

Post by Jay Freedman »

Bob, it's generally true that if a determined attacker can see and read your document, they can -- eventually -- duplicate it and modify it in any way they want. You can make it more or less difficult, but you can't make it impossible.

Legal protection is a different matter. If the document is valuable enough, it could be worth retaining legal counsel and pursuing the attacker in court. You would have to start by preparing proof that the original was yours and the date on which you prepared it; and you would have to establish that the attacker obtained it and used it illegally. If you aren't prepared to spend thousands to obtain justice, though, it probably isn't worth it.

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John Gray
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Re: Read Only

Post by John Gray »

BobH wrote:In Windows, it is my understanding that assigning the 'read only' property to a file means that it can not be changed. Is there a way to set a property so that the file can only be read but not changed or saved?
Linux has more restrictive file permissions than Windows. But that might be a step too far!
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stuck
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Re: Read Only

Post by stuck »

BobH wrote:...ways to protect intellectual property...
We protect the final PDF output that our customers receive from us using Adobe Certified Document Services.

Does that prevent someone duplicating one of our reports and manipulating the content in the process? No because as has already been pointed out, if something can be seen on screen / printed out, it can be retyped from scratch. However any such copy will not validate when opened in Adobe Reader and so is revealed as a fake. The cost of our Adobe CDS Digital ID was negligible in the context of our business but that puts it out of range of casual personal use. Pity, it's really neat the way it works.

However, you could try investigating self-sign certificates?

Ken

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BobH
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Re: Read Only

Post by BobH »

Thank you, Gentlemen!

I guess I was more curious about the issue than expecting any practicable outcome. I realize, of course, that any display can be copied by any of various screen scrape methods. I was trying to verify if it were possible to block saving a file. A screenshot would not include the document metadata, but a file save would making it possible to alter it. I was thinking that if metadata could not be altered that its content might be a way to establish authorship and change history. Of course, I've answered my on question on reflection. The fact that metadata can be altered is the weakness.

My question should have been, "Is there a way to lock the metadata in a file such that copies of the file could be detected?"

Thanks again.

:cheers: :chocciebar: :thankyou:
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stuck
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Re: Read Only

Post by stuck »

BobH wrote:My question should have been, "Is there a way to lock the metadata in a file such that copies of the file could be detected?"
Doesn't that mean applying some sort of digital signature to the file?

Ken

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BobH
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Re: Read Only

Post by BobH »

stuck wrote:
BobH wrote:My question should have been, "Is there a way to lock the metadata in a file such that copies of the file could be detected?"
Doesn't that mean applying some sort of digital signature to the file?

Ken
Possibly. My thinking has been quite circuitous on the subject. I need to give the problem more thought and analysis.

Thanks for the suggestion!

Best to the stucklings!
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