// Update the state according to the information presented in the heartbeat
// processHeartbeat uses return codes for testing purposes
func (s *State) processHeartbeat(hb *heartbeat, i byte) (err error) {
print("Confirming Participant ")
println(i)
// Add the entropy to UpcomingEntropy
th, err := crypto.CalculateTruncatedHash(append(s.upcomingEntropy[:], hb.entropy[:]...))
s.upcomingEntropy = common.Entropy(th)
return
}
// Update the state according to the information presented in the heartbeat
// processHeartbeat uses return codes for testing purposes
func (s *State) processHeartbeat(hb *heartbeat, i participantIndex) int {
// compare EntropyStage2 to the hash from the previous heartbeat
expectedHash, err := crypto.CalculateTruncatedHash(hb.entropyStage2[:])
if err != nil {
log.Fatalln(err)
}
if expectedHash != s.previousEntropyStage1[i] {
s.tossParticipant(i)
return 1
}
// Add the EntropyStage2 to UpcomingEntropy
th, err := crypto.CalculateTruncatedHash(append(s.upcomingEntropy[:], hb.entropyStage2[:]...))
s.upcomingEntropy = common.Entropy(th)
// store entropyStage1 to compare with next heartbeat from this participant
s.previousEntropyStage1[i] = hb.entropyStage1
return 0
}
// Use the entropy stored in the state to generate a random integer [low, high)
// randInt only runs during compile(), when the mutexes are already locked
//
// needs to be converted to return uint64
func (s *State) randInt(low int, high int) (randInt int, err error) {
// verify there's a gap between the numbers
if low == high {
err = fmt.Errorf("low and high cannot be the same number")
return
}
// Convert CurrentEntropy into an int
rollingInt := 0
for i := 0; i < 4; i++ {
rollingInt = rollingInt << 8
rollingInt += int(s.currentEntropy[i])
}
randInt = (rollingInt % (high - low)) + low
// Convert random number seed to next value
truncatedHash, err := crypto.CalculateTruncatedHash(s.currentEntropy[:])
s.currentEntropy = common.Entropy(truncatedHash)
return
}
