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Hi Gordon, The spec says use the low order 3 bytes of the object id and low order 2 bytes of the generation number. Thus encoding for obj = 10 (hex 0A), gen = 0 would be 0A 00 00 00 00, for obj = 30 (hex 1E) would be 1E 00 00 00 00. This can be done in c++ using shifts or unions: int obj = 10; // Object number int gen = 0; // generation number unsigned char appendage[5]; appendage[0] = obj & 0xff; // low byte of word appendage[1] = (obj >> 8) & 0xff; // low middle byte of word appendage[2] = (obj >> 16) & 0xff; // high middle byte appendage[3] = gen & 0xff; appendage[4] = (gen >> 8) & 0xff; .. Jon Anderson Bengt Computer Graphics LLC http://www.bengtcg.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Gordon Campbell Sent: Monday, December 22, 2003 9:05 AM To: [EMAIL PROTECTED] Subject: [PDFdev] Encryption PDFdev is a service provided by PDFzone.com | http://www.pdfzone.com _____________________________________________________________ In order to give myself something to do over the Christmas holiday I'm revisiting my attempt at encrypting a PDF document via my open-source (for Progress 4GL) project. Now, I've gotten to the point where I can correctly generate the User (/U) and Master (/M) entries correctly so I know that my md5 hashing is working. Now I just need to determine the next step ... encrypting the stream or string content. So for this I thought that I'd start simple. Try encrypting the Author ... I got this working ... I can see that it is correct via the Document Properties. With this my Obj ID = 1 and Gen ID = 0 (zero). So it was easy enough to determine how to append that value to my original string. Now my question .... if I had an Object ID of 20 (or say 30) how would I go about determining this 5 byte appendage? For Object ID = 1, the appendage (so to speak) was 0100000000 (in hex). What would the appendage look like for 20 or 30 and how did you do that conversion? Thanks and have a Merry Christmas, Gordon To change your subscription: http://www.pdfzone.com/discussions/lists-pdfdev.html To change your subscription: http://www.pdfzone.com/discussions/lists-pdfdev.html
