1. Problem and Motivation
Security and Power
Insecure
network
Symmetric
Encryption
Technique
Video Encoder
Secure Video Encoder
Attacks
Decryption
Video Decoder
Secure Video Decoder
Battery
-Operated
Devices
Problem and Motivation
Mobile multimedia applications
are vulnerable to security attacks
in wireless networks
Significant computation for
video encryption is expected
on battery-operated mobiles
Evaluate symmetric video
encryption schemes w.r.t. energy
Analytical Study
Experimental Study
50 %
Algorithm
NAIVE
SELECTIVE
Zig-Zag
VEA
Encryption of all frames
Partial encryption
(e.g. Intra-blocks)
Shuffling coefficients
from Quantization
XORing and Half Encryption
using even byte distribution
Moderate
Very Low
High
100 %
59 %
< 1 %
Security
Relative
Energy 10 20 30 40 50 60 70 80 90
FOREMAN.qcif
NEWS.qcif
Video Clips
Measured Energy (Joules)
Negligible Energy Overhead
Encoding without Encryption
Encoding with Encryption (Selective)
Encoding with Encryption (Naïve)

2. Reliability and Power
Critical real-time applications on battery-operated embedded systems
Demand high reliability and low power consumption (eg: Remote Sensing)
Strong relationship between reliability and power consumption with technology advance
Reliability approaches require extra energy consumption (eg: Triple Modular Redundancy)
Power management techniques affect the system reliability (eg: Voltage scaling and soft error rate)
Advance technology causes higher fault rate (eg: lower voltage, higher density)
Composibility contributes system level perspectives with knobs for coordinating and optimizing reliability, energy consumption and time constraints
Increase Power
Reliability Manager: Redundancy
Power Manager: DVS, DPM
Decrease Reliability
COMPOSIBILITY
Coordinator  Optimal Solution
(1) Compute optimal speed
for min energy usage within
deadline
(2) Control knobs
unless feasible for reliability
(3) Apply redundancy to
satisfy reliability
P substrate N+
gate
drain
source
α particle +- -+