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80 lines
3.4 KiB
80 lines
3.4 KiB
dtmc
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// probability of forwarding
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const double PF = 4/5;
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const double notPF = 1/5; // must be 1-PF
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// probability that a crowd member is bad
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const double badC = 167/1000;
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// probability that a crowd member is good
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const double goodC = 833/1000;
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// Total number of protocol runs to analyze
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const int TotalRuns = 5;
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// size of the crowd
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const int CrowdSize = 10;
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module crowds
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// protocol phase
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phase: [0..4] init 0;
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// crowd member good (or bad)
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good: bool init false;
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// number of protocol runs
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runCount: [0..TotalRuns] init 0;
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// observe_i is the number of times the attacker observed crowd member i
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observe0: [0..TotalRuns] init 0;
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observe1: [0..TotalRuns] init 0;
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observe2: [0..TotalRuns] init 0;
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observe3: [0..TotalRuns] init 0;
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observe4: [0..TotalRuns] init 0;
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observe5: [0..TotalRuns] init 0;
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observe6: [0..TotalRuns] init 0;
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observe7: [0..TotalRuns] init 0;
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observe8: [0..TotalRuns] init 0;
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observe9: [0..TotalRuns] init 0;
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// the last seen crowd member
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lastSeen: [0..CrowdSize - 1] init 0;
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// get the protocol started
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[] phase=0 & runCount<TotalRuns -> (phase'=1) & (runCount'=runCount+1) & (lastSeen'=0);
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// decide whether crowd member is good or bad according to given probabilities
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[] phase=1 -> goodC : (phase'=2) & (good'=true) + badC : (phase'=2) & (good'=false);
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// if the current member is a good member, update the last seen index (chosen uniformly)
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[] phase=2 & good -> 1/10 : (lastSeen'=0) & (phase'=3) + 1/10 : (lastSeen'=1) & (phase'=3) + 1/10 : (lastSeen'=2) & (phase'=3) + 1/10 : (lastSeen'=3) & (phase'=3) + 1/10 : (lastSeen'=4) & (phase'=3) + 1/10 : (lastSeen'=5) & (phase'=3) + 1/10 : (lastSeen'=6) & (phase'=3) + 1/10 : (lastSeen'=7) & (phase'=3) + 1/10 : (lastSeen'=8) & (phase'=3) + 1/10 : (lastSeen'=9) & (phase'=3);
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// if the current member is a bad member, record the most recently seen index
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[] phase=2 & !good & lastSeen=0 & observe0 < TotalRuns -> (observe0'=observe0+1) & (phase'=4);
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[] phase=2 & !good & lastSeen=1 & observe1 < TotalRuns -> (observe1'=observe1+1) & (phase'=4);
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[] phase=2 & !good & lastSeen=2 & observe2 < TotalRuns -> (observe2'=observe2+1) & (phase'=4);
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[] phase=2 & !good & lastSeen=3 & observe3 < TotalRuns -> (observe3'=observe3+1) & (phase'=4);
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[] phase=2 & !good & lastSeen=4 & observe4 < TotalRuns -> (observe4'=observe4+1) & (phase'=4);
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[] phase=2 & !good & lastSeen=5 & observe5 < TotalRuns -> (observe5'=observe5+1) & (phase'=4);
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[] phase=2 & !good & lastSeen=6 & observe6 < TotalRuns -> (observe6'=observe6+1) & (phase'=4);
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[] phase=2 & !good & lastSeen=7 & observe7 < TotalRuns -> (observe7'=observe7+1) & (phase'=4);
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[] phase=2 & !good & lastSeen=8 & observe8 < TotalRuns -> (observe8'=observe8+1) & (phase'=4);
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[] phase=2 & !good & lastSeen=9 & observe9 < TotalRuns -> (observe9'=observe9+1) & (phase'=4);
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// good crowd members forward with probability PF and deliver otherwise
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[] phase=3 -> PF : (phase'=1) + notPF : (phase'=4);
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// deliver the message and start over
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[] phase=4 -> (phase'=0);
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endmodule
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label "observe0Greater1" = observe0 > 1;
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label "observeIGreater1" = observe1 > 1 | observe2 > 1 | observe3 > 1 | observe4 > 1 | observe5 > 1 | observe6 > 1 | observe7 > 1 | observe8 > 1 | observe9 > 1;
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label "observeOnlyTrueSender" = observe0 > 1 & observe1 <= 1 & observe2 <= 1 & observe3 <= 1 & observe4 <= 1 & observe5 <= 1 & observe6 <= 1 & observe7 <= 1 & observe8 <= 1 & observe9 <= 1;
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