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							194 lines
						
					
					
						
							11 KiB
						
					
					
				| // CROWDS [Reiter,Rubin] | |
| // Vitaly Shmatikov, 2002 | |
| // Modified by Ernst Moritz Hahn (emh@cs.uni-sb.de) | |
| 
 | |
| // note: | |
| // Change everything marked CWDSIZ when changing the size of the crowd | |
| // Change everything marked CWDMAX when increasing max size of the crowd | |
| 
 | |
| dtmc | |
| 
 | |
| // Model parameters | |
| const double PF;  // forwarding probability | |
| const double badC;  // probability that member is untrustworthy | |
| 
 | |
| // Probability of forwarding | |
| // const double    PF = 0.8; | |
| // const double notPF = 0.2;  // must be 1-PF | |
| 
 | |
| // Probability that a crowd member is bad | |
| // const double  badC = 0.1; | |
| // const double  badC = 0.091; | |
| // const double  badC = 0.167; | |
| // const double goodC = 0.909;  // must be 1-badC | |
| // const double goodC = 0.833;  // must be 1-badC | |
| 
 | |
| const int CrowdSize = 5; // CWDSIZ: actual number of good crowd members | |
| const int TotalRuns = 5; // Total number of protocol runs to analyze | |
| const int MaxGood=20; // CWDMAX: maximum number of good crowd members | |
| 
 | |
| // Process definitions | |
| module crowds | |
| 
 | |
| 	// Auxiliary variables | |
| 	launch:   bool init true;       // Start modeling? | |
| 	newInstance:      bool init false;      // Initialize a new protocol instance? | |
| 	runCount: [0..TotalRuns] init TotalRuns;   // Counts protocol instances | |
| 	start:    bool init false;      // Start the protocol? | |
| 	run:      bool init false;      // Run the protocol? | |
| 	lastSeen: [0..MaxGood] init 0;   // Last crowd member to touch msg | |
| 	good:     bool init false;      // Crowd member is good? | |
| 	bad:      bool init false;      //              ... bad? | |
| 	recordLast: bool init false;    // Record last seen crowd member? | |
| 	badObserve: bool init false;    // Bad members observes who sent msg? | |
| 	deliver:  bool init false;      // Deliver message to destination? | |
| 	done:     bool init false;      // Protocol instance finished? | |
| 
 | |
| 	// Counters for attackers' observations | |
| 	// CWDMAX: 1 counter per each good crowd member | |
| 	observe0:  [0..TotalRuns]; | |
| 	observe1:  [0..TotalRuns]; | |
| 	observe2:  [0..TotalRuns]; | |
| 	observe3:  [0..TotalRuns]; | |
| 	observe4:  [0..TotalRuns]; | |
| 	observe5:  [0..TotalRuns]; | |
| 	observe6:  [0..TotalRuns]; | |
| 	observe7:  [0..TotalRuns]; | |
| 	observe8:  [0..TotalRuns]; | |
| 	observe9:  [0..TotalRuns]; | |
| 	observe10: [0..TotalRuns]; | |
| 	observe11: [0..TotalRuns]; | |
| 	observe12: [0..TotalRuns]; | |
| 	observe13: [0..TotalRuns]; | |
| 	observe14: [0..TotalRuns]; | |
| 	observe15: [0..TotalRuns]; | |
| 	observe16: [0..TotalRuns]; | |
| 	observe17: [0..TotalRuns]; | |
| 	observe18: [0..TotalRuns]; | |
| 	observe19: [0..TotalRuns]; | |
| 	 | |
| 	[] launch -> (newInstance'=true) & (runCount'=TotalRuns) & (launch'=false); | |
| 	// Set up a newInstance protocol instance | |
| 	[] newInstance & runCount>0 -> (runCount'=runCount-1) & (newInstance'=false) & (start'=true); | |
| 	 | |
| 	// SENDER | |
| 	// Start the protocol | |
| 	[] start -> (lastSeen'=0) & (run'=true) & (deliver'=false) & (start'=false); | |
| 	 | |
| 	// CROWD MEMBERS | |
| 	// Good or bad crowd member? | |
| 	[] !good & !bad & !deliver & run -> | |
| 	              1-badC : (good'=true) & (recordLast'=true) & (run'=false) + | |
| 	               badC : (bad'=true)  & (badObserve'=true) & (run'=false); | |
|  | |
| 	// GOOD MEMBERS | |
| 	// Forward with probability PF, else deliver | |
| 	[] good & !deliver & run -> PF : (good'=false) + 1-PF : (deliver'=true); | |
| 	// Record the last crowd member who touched the msg; | |
| 	// all good members may appear with equal probability | |
| 	//    Note: This is backward.  In the real protocol, each honest | |
| 	//          forwarder randomly chooses the next forwarder. | |
| 	//          Here, the identity of an honest forwarder is randomly | |
| 	//          chosen *after* it has forwarded the message. | |
| 	[] recordLast & CrowdSize=2 -> | |
| 	        1/2 : (lastSeen'=0) & (recordLast'=false) & (run'=true) + | |
| 	        1/2 : (lastSeen'=1) & (recordLast'=false) & (run'=true); | |
| 	[] recordLast & CrowdSize=3 -> | |
| 	        1/3 : (lastSeen'=0) & (recordLast'=false) & (run'=true) + | |
| 	        1/3 : (lastSeen'=1) & (recordLast'=false) & (run'=true) + | |
| 	        1/3 : (lastSeen'=2) & (recordLast'=false) & (run'=true); | |
| 	[] recordLast & CrowdSize=4 -> | |
| 	        1/4 : (lastSeen'=0) & (recordLast'=false) & (run'=true) + | |
| 	        1/4 : (lastSeen'=1) & (recordLast'=false) & (run'=true) + | |
| 	        1/4 : (lastSeen'=2) & (recordLast'=false) & (run'=true) + | |
| 	        1/4 : (lastSeen'=3) & (recordLast'=false) & (run'=true); | |
| 	[] recordLast & CrowdSize=5 -> | |
| 	        1/5 : (lastSeen'=0) & (recordLast'=false) & (run'=true) + | |
| 	        1/5 : (lastSeen'=1) & (recordLast'=false) & (run'=true) + | |
| 	        1/5 : (lastSeen'=2) & (recordLast'=false) & (run'=true) + | |
| 	        1/5 : (lastSeen'=3) & (recordLast'=false) & (run'=true) + | |
| 	        1/5 : (lastSeen'=4) & (recordLast'=false) & (run'=true); | |
| 	[] recordLast & CrowdSize=10 -> | |
| 	        1/10 : (lastSeen'=0) & (recordLast'=false) & (run'=true) + | |
| 	        1/10 : (lastSeen'=1) & (recordLast'=false) & (run'=true) + | |
| 	        1/10 : (lastSeen'=2) & (recordLast'=false) & (run'=true) + | |
| 	        1/10 : (lastSeen'=3) & (recordLast'=false) & (run'=true) + | |
| 	        1/10 : (lastSeen'=4) & (recordLast'=false) & (run'=true) + | |
| 	        1/10 : (lastSeen'=5) & (recordLast'=false) & (run'=true) + | |
| 	        1/10 : (lastSeen'=6) & (recordLast'=false) & (run'=true) + | |
| 	        1/10 : (lastSeen'=7) & (recordLast'=false) & (run'=true) + | |
| 	        1/10 : (lastSeen'=8) & (recordLast'=false) & (run'=true) + | |
| 	        1/10 : (lastSeen'=9) & (recordLast'=false) & (run'=true); | |
| 	[] recordLast & CrowdSize=15 -> | |
| 	        1/15 : (lastSeen'=0)  & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=1)  & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=2)  & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=3)  & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=4)  & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=5)  & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=6)  & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=7)  & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=8)  & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=9)  & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=10) & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=11) & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=12) & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=13) & (recordLast'=false) & (run'=true) + | |
| 	        1/15 : (lastSeen'=14) & (recordLast'=false) & (run'=true); | |
| 	[] recordLast & CrowdSize=20 -> | |
| 	        1/20 : (lastSeen'=0)  & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=1)  & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=2)  & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=3)  & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=4)  & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=5)  & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=6)  & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=7)  & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=8)  & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=9)  & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=10) & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=11) & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=12) & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=13) & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=14) & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=15) & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=16) & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=17) & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=18) & (recordLast'=false) & (run'=true) + | |
| 	        1/20 : (lastSeen'=19) & (recordLast'=false) & (run'=true); | |
| 	 | |
| 	// BAD MEMBERS | |
| 	// Remember from whom the message was received and deliver | |
| 	// CWDMAX: 1 rule per each good crowd member | |
| 	[] lastSeen=0  & badObserve & observe0 <TotalRuns -> (observe0' =observe0 +1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=1  & badObserve & observe1 <TotalRuns -> (observe1' =observe1 +1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=2  & badObserve & observe2 <TotalRuns -> (observe2' =observe2 +1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=3  & badObserve & observe3 <TotalRuns -> (observe3' =observe3 +1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=4  & badObserve & observe4 <TotalRuns -> (observe4' =observe4 +1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=5  & badObserve & observe5 <TotalRuns -> (observe5' =observe5 +1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=6  & badObserve & observe6 <TotalRuns -> (observe6' =observe6 +1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=7  & badObserve & observe7 <TotalRuns -> (observe7' =observe7 +1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=8  & badObserve & observe8 <TotalRuns -> (observe8' =observe8 +1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=9  & badObserve & observe9 <TotalRuns -> (observe9' =observe9 +1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=10 & badObserve & observe10<TotalRuns -> (observe10'=observe10+1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=11 & badObserve & observe11<TotalRuns -> (observe11'=observe11+1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=12 & badObserve & observe12<TotalRuns -> (observe12'=observe12+1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=13 & badObserve & observe13<TotalRuns -> (observe13'=observe13+1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=14 & badObserve & observe14<TotalRuns -> (observe14'=observe14+1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=15 & badObserve & observe15<TotalRuns -> (observe15'=observe15+1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=16 & badObserve & observe16<TotalRuns -> (observe16'=observe16+1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=17 & badObserve & observe17<TotalRuns -> (observe17'=observe17+1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=18 & badObserve & observe18<TotalRuns -> (observe18'=observe18+1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 	[] lastSeen=19 & badObserve & observe19<TotalRuns -> (observe19'=observe19+1) & (deliver'=true) & (run'=true) & (badObserve'=false); | |
| 
 | |
| 	// RECIPIENT | |
| 	// Delivery to destination | |
| 	[] deliver & run -> (done'=true) & (deliver'=false) & (run'=false) & (good'=false) & (bad'=false); | |
| 	// Start a newInstance instance | |
| 	[] done -> (newInstance'=true) & (done'=false) & (run'=false) & (lastSeen'=MaxGood); | |
| 	 | |
| endmodule | |
| 
 | |
| label "observe0Greater1" = observe0 > 1; | |
| label "observeIGreater1" = observe1>1|observe2>1|observe3>1|observe4>1; | |
| label "observeOnlyTrueSender" = observe0>1&observe1<=1 & observe2<=1 & observe3<=1 & observe4<=1;
 |