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EncryptwithHeader Sample

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Access locked and protected files in Windows, read and write disks and partitions and more.
#24165
Posted: 03/19/2013 06:24:22
by Manoj Jain (Standard support level)
Joined: 02/28/2013
Posts: 94

EncryptwithHeader Sample VC++ sample

I would like to know what should we expect from the sample, in following case

If I open an encrypted file from masked folder , edit the file, save again

What should I expect:

a. Modified file but encrypted
b. Modified normal file
c. Damaged file


My experiments shows mixed results with same file formats.

In general I found results as below:

Result [a] with docx, xlsx, pptm, txt, xlsm file formats.

Result [b] with rtf, xps formats

Result [c] with doc, xls, ppt, formats


Though files got damaged in almost all cases many times during experiment.

Please let us know what we should expect.
#24166
Posted: 03/19/2013 06:39:14
by Vladimir Cherniga (EldoS Corp.)

Thank you very much for the report.
In all cases it should work as described in a) case. For the other cases, please specify in details, how to reproduce the problem, operation system and filter paths used in test. Also should note, if you detach/attach filter during the tests, it could show file as damaged on a first time open, so it is better to set FlushFilesOnOpen = TRUE for that case.
#24193
Posted: 03/20/2013 07:26:23
by Manoj Jain (Standard support level)
Joined: 02/28/2013
Posts: 94

See the attached jpg created using XLSX file giving complete detail of testing Callbackfilter in C++ sample


#24194
Posted: 03/20/2013 07:41:59
by Vladimir Cherniga (EldoS Corp.)

Thank you for the information, we will check this out as soon as possible. Please specify the exact filter mask you have used during the tests.
#24198
Posted: 03/20/2013 08:47:42
by Manoj Jain (Standard support level)
Joined: 02/28/2013
Posts: 94

Mask used C:\test\*.*
#24200
Posted: 03/20/2013 11:13:08
by Vladimir Cherniga (EldoS Corp.)

I've made the first test with a pdf file (process 2). Using Adobe Reader 9.5 on Vista x32. The file was 100M approximately, file corruption not confirmed. We need a more details how did you reproduce the problem. (May be you can attach a pdf file used in tests)
#24208
Posted: 03/21/2013 00:40:34
by Manoj Jain (Standard support level)
Joined: 02/28/2013
Posts: 94

I tested the pdf and found the file corrupted.

I then un-installed the driver, then installed again

On re-test pdf worked perfectly.

I cannot explain this behavior as I had installed the driver very recently and to best of my knowledge I have not done any other change.

Let me know few things:

Do you require "run as administrator" only for driver installation or all the time

Note: I am running the application as administrator all the time.

I will check again all other file formats reported. But I need an explanation on why driver re-installation was needed just in few days gap.


Thanks.
#24209
Posted: 03/21/2013 04:15:37
by Vladimir Cherniga (EldoS Corp.)

Administrative rights required for installation only. About re-installation, it possible that previous installation still running on a system and requires reboot for new driver binary to load. You should check RebootRequired parameter on driver installation procedure.
#24211
Posted: 03/21/2013 05:35:27
by Manoj Jain (Standard support level)
Joined: 02/28/2013
Posts: 94

I could not understand why on re-installation pdf files work ... while other files were working fine as per report.

Also I tested 3 different pdf files ... the result is not consistent.

I will update on this issue later..
#24212
Posted: 03/21/2013 05:51:21
by Vladimir Cherniga (EldoS Corp.)

Did you use clear installation or install over the previous version of CallbackFilter ? In the first case it could be possible that an old version of drvier worked until reboot. Or it could be question of system caching, when you detach filter and attach again, it could load an old cached version of file. When filter attached, it tries to flush the stale data from cache depends on settings FlushFileOnOpen/FlushFileOnClose. Filter manages the file handles opened when filter attached. For the handles opened before filter attached, it could work unexpected, as any requests with such handles may skipped by the EncrypWithHandle sample, in this case UserContext field in subsequent requests will be NULL.
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200+ components and classes for digital security, signing, encryption and secure networking.

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