A User Centric Security Model for Tamper-Resistant Devices

6.6 Analysis of the Proposed Protocols
application user separation attack.
As is apparent from the table 6.2, the proposed STCPs satises all goals that were described
in section 6.2.3. The protocols that are proposed specically for the smart card
environment (i.e. ICOM) only meet half of the stated goals because the security requirements
for the UCOM are more stringent than for the ICOM [32]. Nevertheless, we still
consider that the proposed STCP should be deployed even in the ICOM and especially
with any future ownership model that supports multi-applications on a smart card under
the Trusted Service Manager (TSM) architecture.
6.6.4 Implementation Results and Performance Measurements
For comparison, we have selected the performance of SSL [182], TLS [183], and public
key-based Kerberos [184] implemented on 32-bit smart cards. We selected the SSL and
TLS because they form the bases of the GlobalPlatform SCP81. Kerberos closely relates
to the card management architecture of Multos (section 5.3). The Multos Certication
Authority acts as a Trusted Third Party (TTP), and the public key-based Kerberos can
be implemented to accommodate the Multos card management framework. The Kerberos
discussed in the performance measures is also implemented on 32bit smart cards [184].
t
Table 6.3: Protocol performance measurement (milliseconds)
Measures SSL TLS Kerberos
STCP SC STCP SP STCP ACA
C1 C2 C1 C2 C1 C2
Average 4200 4300 4240 2998 3091 3395 3532 5843 6098
Best Run NA NA NA 2906 3031 3343 3359 5485 5688
Worse Run NA NA NA 3922 4344 3875 6797 9734 7329
Std Deviation NA NA NA 117.54 96.28 69.82 134.91 191.62 171.13
Note: the above mentioned measurement values for SSL are taken from [182], TLS [183] and
Kerberos [184]. C1 and C2 are 16bit Java Cards. We have rounded up the values to the nearest natural
number except for the standard deviation.
For performance measurements, we use the same test bed conguration described in section
4.8.3. For the STCP SC and STCP SP we implement two entities: a smart card and an SP.
For the STCP ACA we implement an additional entity of administrative authority. Both an
SP and an administrative authority are implemented on a laptop with 1.83 GHz, and 2GB
RAM running on Windows XP. The Java Card implementation of the STCP SP , STCP SC ,
and STCP ACA took 11102, 10382, and 13364 bytes, respectively. The performance measures
listed in the table 6.3 do not include the attestation process, which is listed in table
4.3.
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