You need to do the analysis as described under the core measure and if you feel the need you may encrypt files.
Here are the instructions in AC -
HOW TO DO THIS IN AC: This step requires an internal audit by the practice to make sure adequate security precautions are in place. These features include, but are not limited to, protecting wireless networks with a strong password, authenticating users and maintaining secure user passwords, and encrypting all PHI. Amazing Charts helps you do this in 2 ways. In Administrator Options go to User Configuration (Security) to configure advanced security options. In Amazing Utilities, in the Advance menu is an option for Encryption. Here you may encrypt or decrypt files. Files can only be decrypted on a computer with Amazing Charts installed and the correct password entered.
For more information on Encryption and Advance Security features go to Help or use your F1 Key