1. June 2007
An Experimental Study on Energy Consumption of Video Encryption for Mobile Handheld Devices
Kyoungwoo Lee, Nikil Dutt, Nalini Venkatasubramanian
Donald Bren School of Information and Computer Sciences
University of California, Irvine, CA 92697
{kyoungwl, dutt,
For more details :
Problem and Motivation
Mobile multimedia applications are vulnerable
to security attacks in wireless networks
Significant computation for video encryption is
expected on battery-operated mobile devices
Evaluate symmetric video encryption schemes
from the perspective of energy consumption
both analytically and experimentally
Overview of Secure Video Applications
Analytical Study of Video Encryption Schemes with respect to Energy Consumption
Experimental Study on Tradeoffs between Security and Energy Consumption
Experimental Setup
5 V V
Zaurus
R = 22 ohm R
Power Measurement System
PZaurus = * VZaurus VR
DAQ board with
BNC Connector
Windows XP
1,000 samples/sec
Secure Video Application
(Encoder / Decoder)
DES
H.263
Codec
Device
Driver
OpenSSL
Library
Operating System
(Linux)
Mobile Handheld Hardware
(Sharp Zaurus)
400 MHz Intel XScale
64 MB flash & 32 MB SDRAM
System Architecture
Insecure
network
Symmetric
Encryption
Technique
Compressed
Bit Stream
Encrypted &
Raw
Video
Video Encoder
Motion
Estimation
Quantization
DCT
Entropy
Encoding
Secure Video Encoder
Decompressed
Video Decoder
Decoding
Inverse
IDCT
Compensation
Secure Video Decoder
Attacks
Battery
-Operated
Devices
Decryption
50 %
Analytical Comparison of Video Encryption Schemes
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
High
Moderate
Very Low
Slow
Fast
Very Fast
No Change
Big Increase
100 %
59 %
< 1 %
Security
Speed
Size
Relative
Energy
Significant
Computation
Breaks efficiency
of Video Encoding
Not applicable
for H.263 without
even distribution
Drawback
Naïve encryption scheme consumes twice the energy of Selective encryption scheme
11.37
1.5
74.77 10 20 30 40 50 60 70 80
Application
Measured Energy (Joules)
H.263 Encoder
H.263 Decoder
DES Crypto
Huge
Difference
(98%)
Experimental Results
72.26
75.78
72.87
77.62
74.11 90
FOREMAN.qcif
NEWS.qcif
Video Clips
Encoding without Encryption
Encoding with Encryption (Selective)
Encoding with Encryption (Naïve)
(2.4%)
(1.7%)
Encryption consumes negligible
energy as compared to encoding
Energy consumption of encryption is
negligible irrespective of video clips
Negligible Energy Overhead
11 MB with 300 frames
1:10(IP ratio),10(Quant),full search
Energy Consumption for Varying Quality & Security
Energy overhead for full video encryption is NEGLIGIBLE
Quality
(Quant Scale)
(Full vs. Partial)
(Quant = 1)
Mid-High
(Quant = 4)
Mid-Low
(Quant = 10)
Low
(Quant = 31)
High (Full)
Low (Partial)
Measured
Energy (J)
Overhead
128.2
111.0
92.05
83.56
70.44
69.89
13 %
9 %
2 %
1 %
Appropriate for
mobile video
Studied Video Encryption Schemes
EnergySelective = eDES*SIB
SIBl - size of Intra-blocks in video data
Intra-block
I-frame
P-frame
(DES)
(H.263)
(2) Selective Encryption Scheme
EnergyZig-Zag = eoverhead
eoverhead - energy to shuffle coefficients
Video Encoding
& Zig-Zag Permutation
(H.263 & Shuffle)
(3) Zig-Zag Permutation Scheme
eXOR - energy for XOR
EnergyVEA = ½*(eDES+eXOR)*STotal
(XOR & DES)
(4) Video Encryption Algorithm (VEA)
EnergyNaive=eDES*STotal
eDES - energy to encrypt one byte by DES
STotal - size of the whole video data
(1) Naive Encryption Scheme