Short Message Service (sms) security solution for mobile devices

E. SELECTION 
MATRIX 
Table 8 summarizes the security properties of the various encryption 
schemes and their performances for SMS encryption. The aim of the table is to 
assist application designers in choosing a suitable encryption scheme to encrypt 
SMS for a particular deployment scenario. It is assumed that the suitability for 
SMS as a transport mechanism has already been considered. 
The next Chapter of the thesis describes a simple chat application that 
was implemented using only asymmetric encryption to verify the practicality of 
such an implementation.

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 54
 Confide
ntiality 
Integrity Key 
Management 
Power 
Time 
Overhead 
Symmetric 
Good No. 
Yes, if used 
with 
hashing. 
Easy key generation. 
Difficult key 
distribution.
Low Fast 
Low 
Asymmetric 
Good No. 
Yes, if used 
for digital 
signature 
Easy key generation. 
Easy key distribution 
but need to ensure 
authenticity of public 
key 
Acceptable for 
short key 
lengths. 
Depends on 
usage and 
accessibility to 
charging station. 
Acceptable for 
short key 
lengths 
High for long 
key lengths 
OTP 
Perfect No 
Difficult 
key 
generation. 
Difficult key 
distribution. 
Very Low 
Very fast 
No overhead 
Table 8. Encryption Scheme Selection Matrix 

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 55
IV. DEMONSTRATION APPLICATIONS 
A. OVERVIEW 
The measurement results of the experiment in Chapter III showed that the 
use of asymmetric encryption for SMS is not prohibitively high in a modern 
mobile device. The implementation of asymmetric encryption for SMS allows for 
confidentiality and integrity protection without complex key exchanges, and 
provides opportunities for many applications requiring secure exchange of SMS 
messages. This Chapter describes the implementation of a Secure Chat 
demonstration application that uses asymmetric encryption to encrypt and 
digitally sign SMS messages.