According to an aspect of the invention, there is provided a content
sharing system including: a first device configured to acquire a right
object; a second device configured to acquire a content of the right
object from the first device; a session key generation unit provided in
the first device and the second device and configured to generate a
session key based on mutual authentication; a temporary right object
generation unit provided in the first device and configured to generate a
temporary right object from the right object by using the session key to
supply the generated temporary right to the second device; and a content
play unit provided in the second device and configured to receive the
temporary right object to play the content of the right object acquired
from the first device by using the temporary right object.