Planet PDF Forum Archive

Planet PDF ForumWowsers! This is page is old, head to the LIVE Planet PDF Forum. It features more than 10 conferences, covering everything from beginner to in-depth developer and pre-press discussions. If you wish to continue... one & two archive covers 1999-2011 (160,000 pages).

New Forum | Previous | Next | (P-PDF) Developers

Topic: Problem in Overwriting Digital Signature Contents Key
Conf: (P-PDF) Developers, Msg: 94080
From: saqlain
Date: 8/10/2003 05:42 AM

Hi Digital Signature Guys!
I am implementing a digital signature plug-in using Adobe Acrobat DigSig sample. I choose the PKCS7 signature format. As you know that "DSCommitSign" calls a method named “CreateDummyV” in which it allocates a dummy space for upcoming valid contents (PKCS7). When system calls "DSFinishSign" to overwrite the signature dictionary fields I make a PKCS7 data in "UpdateV" method and store it in the signature dictionary using "DigSigOverwriteHexstring".
Now the basic problem starts from here… I will clear it to you by giving an example… I assigns 3000 bytes for upcoming PKCS7 object coz if the new object will be greater (4000 bytes) than already assigned hex formated string (dummy contents) then it will not be overwritten by "DigSigOverwriteHexstring" and if the new PKCS7 data size is smaller (1200) than already assigned one then "DigSigOverwriteHexstring" padd the left over space with blank space. Atleast to write signature in dictionary i take some extra space but by doing this only my own written plug-in can verify the digital signature and it fails in interpretability checking. Fails by testing with adobe self sign or any other plug-in that is using PKCS7 signature format.
Can any one of you help me in regards? to remove these blank padings or to get the original size of contents while working in the "CreateDummyV" method (to save my self from assigning extra space for upcoming contents). thanks in advance..


PDF In-Depth Free Product Trials Ubiquitous PDF

Debenu Aerialist

The ultimate plug-in for Adobe Acrobat. Advanced splitting, merging, stamping, bookmarking, and link...

Download free demo

Debenu PDF Tools Pro

It's simple to use and will let you preview and edit PDF files, it's a Windows application that makes...

Download free demo

Five visions of a PDF Day

In the world of PDFs or as we like to say Planet (of) PDF, a year isn't a real PDF year without an intense few days of industry knowledge sharing.

May 15, 2018
Platinum Sponsor

Search Planet PDF
more searching options...
Planet PDF Newsletter
Most Popular Articles
Featured Product

Debenu PDF Aerialist

The ultimate plug-in for Adobe Acrobat. Advanced splitting, merging, stamping, bookmarking, and link control. Take Acrobat to the next level.


Adding a PDF Stamp Comment

OK, so you want to stamp your document. Maybe you need to give reviewers some advice about the document's status or sensitivity. This tip from author Ted Padova demonstrates how to add stamps with the Stamp Tool along with related comments.