For the timing channel implementation, we required an
application that would generate a large amount of legiti-
mate trac at a steady pace to make the embedding of a
covert timing channel possible. To accomplish this, we de-
veloped an application that transmits live video from the
camera on the Android device to the remote server. The
application allows the phone to operate as an IP camera
which generates a large amount of legitimate trac. Two
simple protocols were implemented to transmit the video
from device to server: one utilizing UDP and one utilizing
TCP. As mentioned above, many UDP packets do not make
it through the Verizon network and to the remote desti-
nation, and thus TCP was the only successful implementa-
tion. The TCP implementation works by transmitting video
frame by frame. The covert channel is implemented by al-
tering the delays between video frames sent to the server.
Currently, we use two delays (one long and one short). We
encode the contacts list into binary form, and then transmit
a zero by transmitted two short delays, and a one by trans-
mitting two long delays. We signify the beginning and end
of a covert channel transmission by transmitting a short-
long-short-long delay sequence. In future work, we plan to
implement more advanced forms of covert channels such as
model-based channels.