// PRISM Model of hacking a communication
// - Bob and Alice are chatting.
// - Eve wants to hack the messages from Bob.
// - The propability of successfull hacking is 0.05.

smg

player bob
  [receiveB], [readWriteB], [sendB], [waitB]
endplayer

player alice
  [receiveA], [readWriteA], [sendA], [waitA]
endplayer

player eve
  [hackE], [waitE]
endplayer

// 0 bob, 1 eve, 2 alice
global move : [0..2] init 0;
//
global bobSent : [0..1] init 0;
global hacked : [0..1] init 0;

label "hacked" = hacked=1;

module communication
  bobReceived : [0..1] init 0;
  bobWroteMessage : [0..1] init 1;
  aliceReceived : [0..1] init 0;
  aliceWroteMessage : [0..1] init 0;
  aliceSent : [0..1] init 0;

  // bob's communication part
  [receiveB] move=0 & aliceSent=1 -> (bobReceived'=1) & (aliceSent'=0) & (move'=1);
  [readWriteB] move=0 & bobReceived=1 -> (bobWroteMessage'=1) & (bobReceived'=0) & (move'=1);
  [sendB] move=0 & bobWroteMessage=1 -> (bobSent'=1) & (bobWroteMessage'=0) & (move'=1);
  [waitB] move=0 & !(aliceSent=1 | bobReceived=1 | bobWroteMessage=1) -> (move'=1);

  // alice's communication part
  [receiveA] move=2 & bobSent=1 -> (aliceReceived'=1) & (bobSent'=0) & (move'=0);
  [readWriteA] move=2 & aliceReceived=1 -> (aliceWroteMessage'=1) & (aliceReceived'=0) & (move'=0);
  [sendA] move=2 & aliceWroteMessage=1 -> (aliceSent'=1) & (aliceWroteMessage'=0) & (move'=0);
  [waitA] move=2 & !(bobSent=1 | aliceReceived=1 | aliceWroteMessage=1) -> (move'=0);

endmodule

module hacking
  [hackE] move=1 & bobSent=1 -> 0.05: (hacked'=1) & (move'=2) + 0.95: (move'=2);
  [waitE] move=1 & !(bobSent=1) -> (move'=2);
endmodule