If you’re looking for more details on how digital signatures, encryption, and other security features work in Adobe Acrobat and Adobe Reader, here are some good resources updated for v8:
Document Security User Guide for Adobe Acrobat and Adobe Reader Version 8 (PDF, 2.2 MB)
This document describes how to configure and use the application user interface, register a digital ID for use in Acrobat, and manage other people’s public key certificates within your system.
Digital Signature User Guide for Adobe Acrobat and Adobe Reader Version 8 (PDF, 3 MB)
This guide describes the digital signature features of the Acrobat 8.x family of products both for Adobe Acrobat and Adobe Reader Version 8 users as well as for security administrators.
Adobe Acrobat 8 for Microsoft Windows Group Policy and the Active Directory service (PDF, 378KB)
This document describes using Group Policy to deploy Acrobat 8 or Adobe Reader 8 products on a Windows network.
Sharing Acrobat settings and data with FDF files in Acrobat 8 (PDF, 456 KB)
Learn how to use FDF files to exchange data between the Acrobat family of client and server products.