A: Microsoft provides a free tool for bulk encryption/decryption. The Active Directory Rights Management Services Bulk Protection Tool is a command-line tool for bulk decrypting multiple Active Directory (AD) RMS protected files or bulk encrypting multiple files to an RMS rights policy template. You can download the tool from the Microsoft Download Center.
You can use the Bulk Protection Tool in conjunction with the Windows File Classification Infrastructure (FCI) feature. The FCI, introduced in Windows Server 2008 R2, lets administrators define custom classification labels, set up classification and expiration rules, and report on classifications. Administrators can manage FCI from the File Server Resource Manager (FSRM). Using the combination of the classification label that FCI assigns to files and the RMS Bulk Encryption Tool, you can automatically apply RMS protection to files. The Microsoft article "Active Directory Rights Management Services Bulk Protection Tool and File Classification Infrastructure Step-by-Step" explains how to set this process up in greater detail.