Tracking this here because PIM Manager might have to be involved with setting
up/unlocking encrypted EDS address books.

Two approaches:
     1. Encrypt only the vCard data.
     2. Encrypt the entire DB, including indices.

I assume that option 1 is not good enough, because an attacker may be
able to reconstruct contact strings from the indices.

Perhaps http://sqlcipher.net/ is a suitable solution for whole-DB encryption.
Needs further discussion.