A User Centric Security Model for Tamper-Resistant Devices

7.7 Analysis of the Proposed Protocols
Table 7.4: Performance measurement (milliseconds) of the ABPL
Measures SSL TLS Kerberos
ABPL
C1 C2
Average Time 4200 4300 4240 2484 2726
Best Time NA NA NA 2243 2634
Worse Time NA NA NA 2554 2945
Standard Deviation NA NA NA 64.53 76.28
would have enabled us to implement the TEM at the underlying operating system level.
We implemented the TEM at the application level and considered that similar or better
performance can be attained if the TEM is implemented as part of the platform. Because
the application-level implementation of the TEM cannot have memory access to measure
the hash values of the client and server applications, we generated the hash of a xed array
of size 556 bytes to represent an application state. The performance of the hash algorithm
is based on the size of the input data and in real deployment of the protocol scenario it
will depend on the size of the applications. The performance measurements for the ABPL
are listed in table 7.4.
The protocols (PBP and ABP) were executed on 16-bit Java Cards, and the implementation
took 9799 bytes for the PBP and 8374 bytes for the ABP. The performance measurements
were taken from two dierent sets of 16-bit Java Cards, and an average of recorded
measurements for each sets is listed in table 7.5.
Table 7.5: Performance measurement (milliseconds) of the PBP and ABPD
Measures
PBP
ABPD
Set One (C1) Set Two (C2) Set One (C1) Set Two (C2)
Average Time 4436.23 4628.35 2998.71 3091.38
Best Time 4078 4235 2906 3031
Worse Time 5469 5875 3922 4344
Standard Deviation 127.89 133.48 96.32 117.71
Note: Set One (C1) means two Java Cards that are similar to the card C1 specication. Similarly, Set
Two (C2) refers to the set of C2 Java Cards.
The performance measurements in this section are only for reference our implementation,
as the actual performance will vary depending upon the size of the client and server applications
(i.e. hash generation), and the performance of public key operation, symmetric
encryption, and random number generation on a given smart card.
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