In this paper, we adopt the classification of personal information and
hierarchy of services to build a privacy system, in which one communicates
with each other via pipes with different security levels. In each level, one
has the corresponding rights to access each other. The requesters are not
able to be infringed based on the personal information that service obtains
from service providers. Privacy system can decrease the interaction, while in
other circumstance the system strengthens and enhances the privacy
preserving. Thus we strike a balance between two goals of Ubiquitous
Computing: interaction and privacy preserving.