A User Centric Security Model for Tamper-Resistant Devices

B.2 Attestation Protocol
dened in this section are not instantiated with actual value. The instantiation is done in
the system denition of a Casper script.
Processes: Each agent in the system is represented by a CSP process, which is dened
in the #Processes of a Casper script.
Specications: The security requirements against which the protocol is analysed by the
FDR tool are dened in the #Specification section of a Casper script.
B.1.2
System Denition
The system denition describes the actual system that is required to be analysed as part of
the protocol analysis by the FDR tool. The system denition contains four sub-components
that are discussed below:
Type Denition: The variable types that are going to be used in the actual systems are
instantiated in the #Actual variables section of a Casper script. The variables dened
in the #Free variables are instantiated in this section, and the FDR tool will use these
variables during the analysis.
Functions: Any functions dened in the #Free variables have to be dened under the
#Functions heading in a Casper script.
System Denition: The agents that would be present during the execution of the protocol
as part of the FDR analysis are dened under the heading System in a Casper script.
The denition of the agents in this section corresponds to the denition of agents under
the heading Processes of a Casper script.
Intruder: Finally, in the #Intruder Information section of a Casper script we dene the
identity and capability of an intruder in the system againist which the security requirements
stipulated in #Specification are evaluated by the FDR tool.
B.2 Attestation Protocol
The Casper script in this section corresponds to the attestation protocol described in
section 4.7.
#Free variables
SC, CM : Agent
ns, nsp, nt, challenge, response : Nonce
SID1, SID2 : Num
VKey: Agent -> PublicKey
SKey: Agent -> SecretKey
InverseKeys = (sKey, sKey), (VKey, SKey)
#Protocol description
0. -> SC : CM
1. SC -> CM : SID1,{SC, ns, CM,}{sKey}
2. CM -> SC : {CM, ns, nm, challenge, SID2}{sKey}
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