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From Marc Kaufman <m...@eeph.com>
Subject Re: Need help to protect PDF with owner password
Date Tue, 21 May 2019 23:45:39 GMT
Which is, of course, a violation of the "agreement" between PDF and 
Readers (ignored by everyone, it seems, except Adobe). In 
Acrobat/Reader, you need to open with the Owner password in order to 
change permissions. Opening with the User password should honor 
permissions and not allow changing of permissions.

Marc

On 5/21/2019 9:42 AM, Tilman Hausherr wrote:
> Am 17.05.2019 um 09:47 schrieb RJC 2009:
>> Here is my test program which is trying to disable the printing 
>> option and
>> protect the document with an owner password.
>>
>> However, if I use the resultant PDF and run the program again with a
>> DIFFERENT owner password then it ENABLE the printing option.
>>
>>
>>
>> Basically I need to disable the printing option in PDF with an owner
>> password and the printing option cannot be enabled back without using 
>> the
>> original owner password.
>
>
> I should have read the text more carefully (and continue reading after 
> "2.0.5"). This is by design. When you open with the user password then 
> the file is decrypted and can be manipulated, reencrypted, everything. 
> The owner password is just an extra so that a software can decide that 
> you're the owner. That is why there are so many tools on the internet 
> that allow to change the permissions of PDF files.
>
> Read also this:
>
> https://www.cs.cmu.edu/~dst/Adobe/Gallery/anon21jul01-pdf-encryption.txt
>
>
> Tilman
>
>
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