Short Message Service (sms) security solution for mobile devices

15. NUMBER OF 
PAGES
113 
14. SUBJECT TERMS
GSM security, SMS security, mobile device security, encryption, mobile device performance 
analysis, secure chat 
16. PRICE CODE
17. SECURITY 
CLASSIFICATION OF 
REPORT
Unclassified 
18. SECURITY 
CLASSIFICATION OF THIS 
PAGE 
Unclassified 
19. SECURITY 
CLASSIFICATION OF 
ABSTRACT 
Unclassified 
20. LIMITATION OF 
ABSTRACT 
 
UL 
NSN 7540-01-280-5500 
S
tandard Form 298 (Rev. 2-89)
Prescribed by ANSI Std. 239-18

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Approved for public release; distribution is unlimited. 
SHORT MESSAGE SERVICE (SMS) SECURITY SOLUTION
FOR MOBILE DEVICES 
Yu Loon Ng 
Major, Singapore Navy 
B.Eng., Nanyang Technological University, 1997 
Submitted in partial fulfillment of the 
requirements for the degree of 
MASTER OF SCIENCE IN COMPUTER SCIENCE 
from the 
NAVAL POSTGRADUATE SCHOOL 
December 2006 
Author: 
Yu Loon Ng 
Approved by:
Gurminder Singh 
Thesis Advisor 
John Gibson 
Co-Advisor 
Peter Denning 
Chairman, Department of Computer Science 

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ABSTRACT 
This thesis focuses on the security of Short Message Service (SMS) and 
the Global System for Mobile communication (GSM) network, and the use of 
encryption to protect SMS messages. A detailed study of the GSM network, the 
SMS protocol and various encryption schemes was conducted to understand the 
properties of different encryption schemes and their applicability to SMS 
messages. An experiment was conducted to measure the actual performance of 
various encryption schemes on a modern smart phone. An analysis of the 
encryption scheme properties and the performance measurement was then 
conducted to select a suitable scheme for SMS encryption. The selected scheme 
was implemented in the form of a Secure SMS Chat application to validate the 
viability of the selected encryption scheme. Potential applications of secure SMS 
in military settings are also discussed.

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