PLUGGED IN
Preserving the evidence

By Simson L Garfinkel, 05/13/99

or years, Adobe's Acrobat system has been the gold standard for publishing printed documents over the Internet.

Most computer companies distribute their manuals as Acrobat ''PDF'' (Portable Document Format) files from their Web sites, letting customers download the files and print them out.

The big advantage of PDF is that you can view a PDF file and print it out on almost any computer, no matter whether you have a Windows-based PC, a Macintosh, or even a UNIX workstation.

The second advantage of PDF is faithfulness: PDF documents are designed to look and print the same on every combination of computer and printer. That's why the Internet Revenue Service distributes tax forms in PDF format, and why a growing number of scientists are using Acrobat and PDF to distribute preprints of their scientific papers.

Last month, Adobe released version 4 of its preeminent Acrobat software. This new package has powerful features for creating and managing PDF files. It's also a handy tool if you want to sue somebody over their Web site.

For the litigation -minded, Acrobat 4 is a breakthrough. The new product will automatically download pages from the Web and use them to create a PDF file, preserving the text, links, and images. You can then take the Web site, digitally sign it, and save it in a single file. This is useful because when there is objectionable information on a Web site, it can change quickly. Acrobat 4 gives attorneys and others a powerful tool for preserving the evidence.

The ability to download all the images and pages from the Web is great even if you aren't going to take somebody to court. For example, a salesman going on the road could download his company's Web site. He could then give a fast presentation on a laptop computer, using Acrobat, without having to deal with the slowness of a modem connection.

Acrobat has always been great for electronic forms. A small newsletter, for example, might use Acrobat to create a form for advertising insertion orders. The sales manager could then keep a copy of the form's PDF file on her computer's desktop. When somebody needs the form, she could print it out and send a paper copy, fax it using her fax modem, or e-mail the Acrobat file. With Acrobat 4, you can also generate Web pages complete with complex JavaScript.

Although Acrobat 4 has a lot more options than its predecessor, the program is actually easier to use. For example, when you go to create an Acrobat file using Adobe's ''Acrobat Distiller'' program, there is a simple pull-down menu that lets you optimize the PDF file for screen display, for printing, or for a printing press. With the previous version of Acrobat, you had to go into several configuration screens and change about a dozen options to get the correct results.

Another problem that I had with Acrobat version 3 was deciding between Adobe's PDF Writer and the Acrobat Distiller. Both programs can be used to create PDF files. The PDF Writer program was easier to use, but the Distiller did a better job. With Acrobat 4 you still have the choice of Distiller and the Writer, but both are easy to use. And, Distiller still does a better job.

Like its predecessor, Acrobat 4 also has a lot of tools for editing Acrobat files. You can change text, add annotations, delete pages from files, or combine Acrobat files. If you discover a glitch in a big manuscript, you can go in and fix the error, rather than regenerating the original PDF file.

Once you have created a PDF file, you can password-protect it. This prevents somebody else from opening the

file without knowing the password. Unlike the password systems used by Microsoft Word and Word Perfect, Acrobat's password system is based on RSA Data Security's encryption technology. This makes it much harder for somebody to access the contents of your Acrobat files without your permission. Besides the password, you can also disallow printing, changing, selecting text, and making annotations.

As I hinted above, Acrobat 4 adds a comprehensive digital signature system for documents. With Acrobat 4 you can create your own digital signature. You can then use this signature to digitally ''sign'' a PDF file. Along with the signature you can specify that you are the author, that you have approved the file, that the file is certified, and so on. This is an important step for giving electronic documents the legal standing that paper documents now enjoy.

Finally, one of the best things about Acrobat 4 is file compatibility. I could easily read back all of the files that I created with Acrobat 4 with the freely-available Acrobat 3 reader. I wish that other companies would follow Adobe's lead by creating software that has both forward and backward file compatibility.

Indeed, my only objection to Acrobat 4 is the price - a rather steep $230 each for the Macintosh and Windows versions. If you don't want to pay for Acrobat but you need to generate PDF files, you might look into the program GhostScript. Available for UNIX, Linux, Windows, and many other operating systems, GhostScript has the ability to generate its own PDF files that can be read back with the Acrobat reader. Unfortunately, GhostScript's PDF files tend to be between 10 and 100 times larger than the compact PDF files that Adobe's

Distiller creates.

Technology writer Simson L. Garfinkel can be reached at plugged-in@simson.net

This story ran on page D04 of the Boston Globe on 05/13/99.
© Copyright 1999 Globe Newspaper Company.