A User Centric Security Model for Tamper-Resistant Devices

B.5 Application Acquisition and Contractual Agreement Protocol
B.5 Application Acquisition and Contractual Agreement Protocol
The Casper script in this section corresponds to the Application Acquisition and Contractual
Agreement Protocol (STCP ACA ) described in section 6.5.
#Free variables
datatype Field = Gen | Exp(Field, Num) unwinding 2
halfkeySP, halfkeySC, DHKey : Field
datatype ACAPKeys = MAC(Field, Num, Num) unwinding 2
EnKey, MaKey : ACAPKeys
SC, SP, User, TSM: Agent
User: tIdentities
Appi: ApplicationIdentity
CardID, SeudoAppi: SeudoIdentities
gSC, gSP: Num
nSC, nSP, nTSM: Nonce
SCOS: SmartCardOS
App: SPApplication
f: HashFunction
VKey: Agent->PublicKey
SKey: Agent->SecretKey
TEKey, TAKey : SessionKey
InverseKeys = (VKey, SKey), (EnKey, EnKey), (MaKey, MaKey), (TEKey, TEKey),\
(TAKey, TAKey)
#Protocol description
0. -> SP : SC
[SC!=SP]
1. SP -> SC : nSP, Exp(Gen,gSP)%halfkeySP
[SC!=SP]
2. SC -> SP : nSC, Exp(Gen,gSC)%halfkeySC
[SP != SC]
3. SP -> SC: nSP, nSC
4. SC -> SP: {{{SCi, Useri, nSP, nSC}{SKey(User)}}{EnKey}}{MaKey}
5. SP -> SC : {{{SPi, Appi, nSC, nSP}{SKey(SP)}}{EnKey}}{MaKey}
6. SC -> SP : {{{f(SCOS)%saveHash, SCi, Useri, SPi, nSC, nSP}{SKey(SC)}}\
{EnKey}}{MaKey}
7. SP -> SC : {{App}{EnKey}}{MaKey}
8. SC -> SP : {{{f(App), SPi, Appi, SCi, Useri, nSP, nSC}{SKey(SC)}}\
{EnKey}}{MaKey}
9. SP -> SC : {{{saveHash%f(SCOS), f(App), SCi, Useri, SPi, nSP, nSC}\
{SKey(SP)}}{EnKey}}{MaKey}
10. SC -> TSM : CardID, {{TSMi, SCi, Useri, nSC, SeudoAppi}{TEKey}}{TAKey}
11. TSM -> SC : {{{TSMi, SCi, Useri, SeudoAppi, nTSM, nSC}{SKey(TSM)}}\
{TEKey}}{TAKey}
#Actual variables
SCard, SProvider, USER, TrustedSM, MaliciousEntity: Agent
ISCard, ISProvider, IUSER, ITrustedSM, IMaliciousEntity: AgentIdentities
GSC, GSP, GMalicious: Num
NSC, NSP, NTSM, NMalicious: Nonce
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