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Posted to fop-dev@xmlgraphics.apache.org by "J.Pietschmann" <j3...@yahoo.de> on 2003/03/09 23:44:27 UTC
PDF Encryption in HEAD
Hi all,
I tried to get PDF encryption into HEAD and failed.
Most of the problem is that PDFXObject no longer has a reference
to the PDFDocument, where the encryption object resides in the patch.
I'm not sure how important this is, the encryption filter is
different from the other filters: it takes the number+generation
of something, however, at some instances it takes the number+gen
from the XObject, at others (ICCStream) from the stream it is
applied. I have not enough knowledge of PDF encryption to sort
this out. Actually, I didn't try the code from the maintentance
branch with an image (hint, hint: need GIF/BMP, JPG with ICC and
EPS to test. Jeremias: this appears to be your speciality...).
Any hints how to proceed?
J.Pietschmann
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RE: PDF Encryption in HEAD
Posted by Bernard D'Have <bd...@wanadoo.be>.
Yes I understand
Will try
Bernard
> -----Original Message-----
> From: Jeremias Maerki [mailto:dev.jeremias@greenmail.ch]
> Sent: 13 March, 2003 22:00
> To: fop-dev@xml.apache.org
> Subject: Re: PDF Encryption in HEAD
>
>
> Wanna do it yourself and send a patch? I want to invest my resources
> into the redesign. I hope you understand.
>
> On 13.03.2003 21:30:30 Bernard D'Have wrote:
> > Can you port your change to the maintenance branch?
> > I'm very interested to have encryption with JDK1.3.
>
>
> Jeremias Maerki
>
>
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Re: PDF Encryption in HEAD
Posted by Jeremias Maerki <de...@greenmail.ch>.
Wanna do it yourself and send a patch? I want to invest my resources
into the redesign. I hope you understand.
On 13.03.2003 21:30:30 Bernard D'Have wrote:
> Can you port your change to the maintenance branch?
> I'm very interested to have encryption with JDK1.3.
Jeremias Maerki
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Re: PDF Encryption in HEAD
Posted by Jeremias Maerki <de...@greenmail.ch>.
Yes, redesign happens in HEAD. Thanks. I'll be after it, too, today.
On 14.03.2003 03:14:31 Patrick C. Lankswert wrote:
> Be more than happy to look at it. Did you commit to HEAD or else where?
Jeremias Maerki
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Re: PDF Encryption in HEAD
Posted by Jeremias Maerki <de...@greenmail.ch>.
Thanks for the pointer. I hope I can come up with something useful
tomorrow.
On 13.03.2003 21:02:57 J.Pietschmann wrote:
> Jeremias Maerki wrote:
> > I've just committed PDF encryption support by Patrick C. Lankswert to
> > the redesign. The bad message is that it doesn't work yet. I get blank
> > pages in Acrobat when enabled, although the PDF looks good when compared
> > with one generated by the maintenance branch. I guess that's the same
> > problem you had, Jörg?
>
> On closer inspection this seems to be the problem: you got
> number+generation from the stream into the filter for *every*
> XObject, but the original patch used number/gen from the XObject
> for all objects except image pixel streams and the JPG ICC
> stream.
>
> That's why I didn't commit the patch: I didn't want to re-add
> the PDFDocument reference to PDFXObject in order to get the
> add the encryption filter after the makeStream() without asking
> why the reference had been dropped on the way from maintenance
> to HEAD.
Jeremias Maerki
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Re: PDF Encryption in HEAD
Posted by Jeremias Maerki <de...@greenmail.ch>.
Ok, now I'm a bit smarter. It took me pretty long to realize what was
really wrong that I got blank pages. The real reason was that if you
don't have any filters active that have a name Acrobat Reader has
problems if the stream is encrypted. As soon as you add the Flate filter,
for example, the page is displayed. So what Jörg told me was already one
step further down the road. I wasn't there at that time.
Now I also understand what you are discussing. After poking around the
code I realized I don't like the way filters are realized at all. The
content of the StreamCache instances gets abused. First you fill in the
raw contents, then apply the filters. The result gets stored in the
place of the raw contents. If you don't object I will rework the filter
stuff so the filters get applied later, namely when it's time to
serialize to the OutputStream. The encoding will be reworked from
encode(in, out) calls to a chain out FilterOutputStream descendant (as
done for the PostScript renderer). That should also reduce the number of
buffer reallocations a bit and improve performance because the buffers
don't get copied around so many times. Or so I hope. If nothing else it
should clean up the design and make it easier to apply
filters/encryption in a more uniform way. The code is currently
scattered all around the package and in the PDF renderer package.
While doing the above work I also realized that the font support was
more or less broken. I've fixed it along the way as good as it went.
I'll add the changes soon. But now I have to atend to other duties first.
See ya.
On 14.03.2003 00:00:37 Keiron Liddle wrote:
> > That's why I didn't commit the patch: I didn't want to re-add
> > the PDFDocument reference to PDFXObject in order to get the
> > add the encryption filter after the makeStream() without asking
> > why the reference had been dropped on the way from maintenance
> > to HEAD.
>
> The PDFDocument was used in the constructor to create ICCStreams for jpeg
> images. This seemed all to specific and was moved to the setup for the
> FopPDFImage.
Jeremias Maerki
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Re: PDF Encryption in HEAD
Posted by "J.Pietschmann" <j3...@yahoo.de>.
Jeremias Maerki wrote:
> I've just committed PDF encryption support by Patrick C. Lankswert to
> the redesign. The bad message is that it doesn't work yet. I get blank
> pages in Acrobat when enabled, although the PDF looks good when compared
> with one generated by the maintenance branch. I guess that's the same
> problem you had, Jörg?
On closer inspection this seems to be the problem: you got
number+generation from the stream into the filter for *every*
XObject, but the original patch used number/gen from the XObject
for all objects except image pixel streams and the JPG ICC
stream.
That's why I didn't commit the patch: I didn't want to re-add
the PDFDocument reference to PDFXObject in order to get the
add the encryption filter after the makeStream() without asking
why the reference had been dropped on the way from maintenance
to HEAD.
J.Pietschmann
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RE: PDF Encryption in HEAD
Posted by Bernard D'Have <bd...@wanadoo.be>.
many thanks
I will try
Bernard
> -----Original Message-----
> From: J.Pietschmann [mailto:j3322ptm@yahoo.de]
> Sent: 13 March, 2003 22:57
> To: fop-dev@xml.apache.org
> Subject: Re: PDF Encryption in HEAD
>
>
> Bernard D'Have wrote:
> > Can you port your change to the maintenance branch?
> > I'm very interested to have encryption with JDK1.3.
>
> Well, now build support depends on JCE rather than the JDK 1.4
> presence check.
>
> J.Pietschmann
>
>
>
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Re: PDF Encryption in HEAD
Posted by "J.Pietschmann" <j3...@yahoo.de>.
Bernard D'Have wrote:
> Can you port your change to the maintenance branch?
> I'm very interested to have encryption with JDK1.3.
Well, now build support depends on JCE rather than the JDK 1.4
presence check.
J.Pietschmann
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Re: PDF Encryption in HEAD
Posted by "J.Pietschmann" <j3...@yahoo.de>.
Bernard D'Have wrote:
> Can you port your change to the maintenance branch?
> I'm very interested to have encryption with JDK1.3.
You only have to compile with 1.4 currently, it will run with
1.3 too as long as a JCE impl is in the classpath.
J.Pietschmann
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RE: PDF Encryption in HEAD
Posted by Bernard D'Have <bd...@wanadoo.be>.
Can you port your change to the maintenance branch?
I'm very interested to have encryption with JDK1.3.
Many thanks,
Bernard
> -----Original Message-----
> From: Jeremias Maerki [mailto:dev.jeremias@greenmail.ch]
> Sent: 13 March, 2003 18:00
> To: fop-dev@xml.apache.org
> Subject: Re: PDF Encryption in HEAD
>
>
> Hi crypto-guys!
>
> I've just committed PDF encryption support by Patrick C. Lankswert to
> the redesign. The bad message is that it doesn't work yet. I get blank
> pages in Acrobat when enabled, although the PDF looks good when compared
> with one generated by the maintenance branch. I guess that's the same
> problem you had, Jörg? Well, and I haven't enabled encryption everywhere,
> yet. That shouldn't be a problem right now, because I've extended the
> stuff to be completely optional depending on the availability of JCE
> and/or cryptographic algorithms necessary. No need for java-1.3/java-1.4
> directories, which is actually strange if you have JCE installed on JDK
> 1.3. The stuff looks out for "javax.crypto.Cipher" to be present to
> determine if JCE is available. A seperate check looks for the necessary
> algorithms (RC4 and MD5).
>
> My stuff is configured via the FOUserAgent which can now hold a
> PDFEncryptionParams object containing the passwords and permissions. If
> is null (default) no encryption happens.
>
> I thought I just commit my stuff and we'll figure out what's wrong based
> on that code. Better this than nothing. I'll continue my investigations
> tomorrow. Maybe Patrick could have a look at the stuff. Maybe you finds
> something?
>
> On 09.03.2003 23:44:27 J.Pietschmann wrote:
> > Hi all,
> > I tried to get PDF encryption into HEAD and failed.
> > Most of the problem is that PDFXObject no longer has a reference
> > to the PDFDocument, where the encryption object resides in the patch.
> > I'm not sure how important this is, the encryption filter is
> > different from the other filters: it takes the number+generation
> > of something, however, at some instances it takes the number+gen
> > from the XObject, at others (ICCStream) from the stream it is
> > applied. I have not enough knowledge of PDF encryption to sort
> > this out. Actually, I didn't try the code from the maintentance
> > branch with an image (hint, hint: need GIF/BMP, JPG with ICC and
> > EPS to test. Jeremias: this appears to be your speciality...).
> >
> > Any hints how to proceed?
>
>
> Jeremias Maerki
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: fop-dev-unsubscribe@xml.apache.org
> For additional commands, email: fop-dev-help@xml.apache.org
>
>
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RE: PDF Encryption in HEAD
Posted by "Patrick C. Lankswert" <PL...@InsightBB.COM>.
Jeremias,
Be more than happy to look at it. Did you commit to HEAD or else where?
Pat
-----Original Message-----
From: Jeremias Maerki [mailto:dev.jeremias@greenmail.ch]
Sent: Thursday, March 13, 2003 12:00 PM
To: fop-dev@xml.apache.org
Subject: Re: PDF Encryption in HEAD
Hi crypto-guys!
I've just committed PDF encryption support by Patrick C. Lankswert to
the redesign. The bad message is that it doesn't work yet. I get blank
pages in Acrobat when enabled, although the PDF looks good when compared
with one generated by the maintenance branch. I guess that's the same
problem you had, Jörg? Well, and I haven't enabled encryption everywhere,
yet. That shouldn't be a problem right now, because I've extended the
stuff to be completely optional depending on the availability of JCE
and/or cryptographic algorithms necessary. No need for java-1.3/java-1.4
directories, which is actually strange if you have JCE installed on JDK
1.3. The stuff looks out for "javax.crypto.Cipher" to be present to
determine if JCE is available. A seperate check looks for the necessary
algorithms (RC4 and MD5).
My stuff is configured via the FOUserAgent which can now hold a
PDFEncryptionParams object containing the passwords and permissions. If
is null (default) no encryption happens.
I thought I just commit my stuff and we'll figure out what's wrong based
on that code. Better this than nothing. I'll continue my investigations
tomorrow. Maybe Patrick could have a look at the stuff. Maybe you finds
something?
On 09.03.2003 23:44:27 J.Pietschmann wrote:
> Hi all,
> I tried to get PDF encryption into HEAD and failed.
> Most of the problem is that PDFXObject no longer has a reference
> to the PDFDocument, where the encryption object resides in the patch.
> I'm not sure how important this is, the encryption filter is
> different from the other filters: it takes the number+generation
> of something, however, at some instances it takes the number+gen
> from the XObject, at others (ICCStream) from the stream it is
> applied. I have not enough knowledge of PDF encryption to sort
> this out. Actually, I didn't try the code from the maintentance
> branch with an image (hint, hint: need GIF/BMP, JPG with ICC and
> EPS to test. Jeremias: this appears to be your speciality...).
>
> Any hints how to proceed?
Jeremias Maerki
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Re: PDF Encryption in HEAD
Posted by Jeremias Maerki <de...@greenmail.ch>.
Hi crypto-guys!
I've just committed PDF encryption support by Patrick C. Lankswert to
the redesign. The bad message is that it doesn't work yet. I get blank
pages in Acrobat when enabled, although the PDF looks good when compared
with one generated by the maintenance branch. I guess that's the same
problem you had, Jörg? Well, and I haven't enabled encryption everywhere,
yet. That shouldn't be a problem right now, because I've extended the
stuff to be completely optional depending on the availability of JCE
and/or cryptographic algorithms necessary. No need for java-1.3/java-1.4
directories, which is actually strange if you have JCE installed on JDK
1.3. The stuff looks out for "javax.crypto.Cipher" to be present to
determine if JCE is available. A seperate check looks for the necessary
algorithms (RC4 and MD5).
My stuff is configured via the FOUserAgent which can now hold a
PDFEncryptionParams object containing the passwords and permissions. If
is null (default) no encryption happens.
I thought I just commit my stuff and we'll figure out what's wrong based
on that code. Better this than nothing. I'll continue my investigations
tomorrow. Maybe Patrick could have a look at the stuff. Maybe you finds
something?
On 09.03.2003 23:44:27 J.Pietschmann wrote:
> Hi all,
> I tried to get PDF encryption into HEAD and failed.
> Most of the problem is that PDFXObject no longer has a reference
> to the PDFDocument, where the encryption object resides in the patch.
> I'm not sure how important this is, the encryption filter is
> different from the other filters: it takes the number+generation
> of something, however, at some instances it takes the number+gen
> from the XObject, at others (ICCStream) from the stream it is
> applied. I have not enough knowledge of PDF encryption to sort
> this out. Actually, I didn't try the code from the maintentance
> branch with an image (hint, hint: need GIF/BMP, JPG with ICC and
> EPS to test. Jeremias: this appears to be your speciality...).
>
> Any hints how to proceed?
Jeremias Maerki
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Re: PDF Encryption in HEAD
Posted by Jeremias Maerki <de...@greenmail.ch>.
I'll have a look at it (Tuesday or Wednesday).
On 09.03.2003 23:44:27 J.Pietschmann wrote:
> I tried to get PDF encryption into HEAD and failed.
> Most of the problem is that PDFXObject no longer has a reference
> to the PDFDocument, where the encryption object resides in the patch.
> I'm not sure how important this is, the encryption filter is
> different from the other filters: it takes the number+generation
> of something, however, at some instances it takes the number+gen
> from the XObject, at others (ICCStream) from the stream it is
> applied. I have not enough knowledge of PDF encryption to sort
> this out. Actually, I didn't try the code from the maintentance
> branch with an image (hint, hint: need GIF/BMP, JPG with ICC and
> EPS to test. Jeremias: this appears to be your speciality...).
>
> Any hints how to proceed?
Jeremias Maerki
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RE: PDF Encryption in HEAD
Posted by "Patrick C. Lankswert" <PL...@InsightBB.COM>.
The encryption filter uses the number and generation as part of the hash to
generate the key for a given object. In short, the encryption key is
different for every object and is based on the number and generation of the
object. I would have preferred something simpler but the PDFXObject is not
what is streamed. It was the PDFICCStream which does not have the number and
generation properly set.
If someone has a suitable example with the various image formats, I will
test, verify and correct an issues.
Pat
-----Original Message-----
From: J.Pietschmann [mailto:j3322ptm@yahoo.de]
Sent: Sunday, March 09, 2003 5:44 PM
To: fop-dev@xml.apache.org
Subject: PDF Encryption in HEAD
Hi all,
I tried to get PDF encryption into HEAD and failed.
Most of the problem is that PDFXObject no longer has a reference
to the PDFDocument, where the encryption object resides in the patch.
I'm not sure how important this is, the encryption filter is
different from the other filters: it takes the number+generation
of something, however, at some instances it takes the number+gen
from the XObject, at others (ICCStream) from the stream it is
applied. I have not enough knowledge of PDF encryption to sort
this out. Actually, I didn't try the code from the maintentance
branch with an image (hint, hint: need GIF/BMP, JPG with ICC and
EPS to test. Jeremias: this appears to be your speciality...).
Any hints how to proceed?
J.Pietschmann
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