You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
69 lines
2.5 KiB
69 lines
2.5 KiB
dtmc
|
|
|
|
// probability of forwarding
|
|
const double PF = 4/5;
|
|
const double notPF = 1/5; // must be 1-PF
|
|
// probability that a crowd member is bad
|
|
const double badC = 167/1000;
|
|
// probability that a crowd member is good
|
|
const double goodC = 833/1000;
|
|
// Total number of protocol runs to analyze
|
|
const int TotalRuns = 5;
|
|
// size of the crowd
|
|
const int CrowdSize = 5;
|
|
|
|
module crowds
|
|
// protocol phase
|
|
phase: [0..4] init 0;
|
|
|
|
// crowd member good (or bad)
|
|
good: bool init false;
|
|
|
|
// number of protocol runs
|
|
runCount: [0..TotalRuns] init 0;
|
|
|
|
// observe_i is the number of times the attacker observed crowd member i
|
|
observe0: [0..TotalRuns] init 0;
|
|
|
|
observe1: [0..TotalRuns] init 0;
|
|
|
|
observe2: [0..TotalRuns] init 0;
|
|
|
|
observe3: [0..TotalRuns] init 0;
|
|
|
|
observe4: [0..TotalRuns] init 0;
|
|
|
|
// the last seen crowd member
|
|
lastSeen: [0..CrowdSize - 1] init 0;
|
|
|
|
// get the protocol started
|
|
[] phase=0 & runCount<TotalRuns -> 1: (phase'=1) & (runCount'=runCount+1) & (lastSeen'=0);
|
|
|
|
// decide whether crowd member is good or bad according to given probabilities
|
|
[] phase=1 -> goodC : (phase'=2) & (good'=true) + badC : (phase'=2) & (good'=false);
|
|
|
|
// if the current member is a good member, update the last seen index (chosen uniformly)
|
|
[] phase=2 & good -> 1/5 : (lastSeen'=0) & (phase'=3) + 1/5 : (lastSeen'=1) & (phase'=3) + 1/5 : (lastSeen'=2) & (phase'=3) + 1/5 : (lastSeen'=3) & (phase'=3) + 1/5 : (lastSeen'=4) & (phase'=3);
|
|
|
|
// if the current member is a bad member, record the most recently seen index
|
|
[] phase=2 & !good & lastSeen=0 & observe0 < TotalRuns -> 1: (observe0'=observe0+1) & (phase'=4);
|
|
[] phase=2 & !good & lastSeen=1 & observe1 < TotalRuns -> 1: (observe1'=observe1+1) & (phase'=4);
|
|
[] phase=2 & !good & lastSeen=2 & observe2 < TotalRuns -> 1: (observe2'=observe2+1) & (phase'=4);
|
|
[] phase=2 & !good & lastSeen=3 & observe3 < TotalRuns -> 1: (observe3'=observe3+1) & (phase'=4);
|
|
[] phase=2 & !good & lastSeen=4 & observe4 < TotalRuns -> 1: (observe4'=observe4+1) & (phase'=4);
|
|
|
|
// good crowd members forward with probability PF and deliver otherwise
|
|
[] phase=3 -> PF : (phase'=1) + notPF : (phase'=4);
|
|
|
|
// deliver the message and start over
|
|
[] phase=4 -> 1: (phase'=0);
|
|
|
|
endmodule
|
|
|
|
label "observe0Greater1" = observe0>1;
|
|
label "observe1Greater1" = observe1>1;
|
|
label "observe2Greater1" = observe2>1;
|
|
label "observe3Greater1" = observe3>1;
|
|
label "observe4Greater1" = observe4>1;
|
|
label "observeIGreater1" = observe1>1|observe2>1|observe3>1|observe4>1;
|
|
label "observeOnlyTrueSender" = observe0>1&observe1<=1 & observe2<=1 & observe3<=1 & observe4<=1;
|