Rename "epoch" to "time to live" (ttl) to avoid ambiguity

DP-3T / documents

Decentralized Privacy-Preserving Proximity Tracing -- Documents

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Rename "epoch" to "time to live" (ttl) to avoid ambiguity #256

Open jaromil opened 4 years ago

jaromil commented 4 years ago

Both in the documents and in the reference implementation the term epoch is used to indicate the minutes a single ephid should be broadcasted before using the next one for the day.

I recommend renaming this to ttl (time to live) to align with usual naming and avoid misunderstanding since "epoch" usually means something else in computer science.

HeNRGi commented 4 years ago

'time to live' may not be the best choice given that we're dealing with a deadly virus?

jaromil commented 4 years ago

Actually we figured it out pretty well (IMHO) in this new implementation: https://github.com/dyne/pangolin/blob/master/src/dp3t.h its a minimalist approach, we reduced DP3T to 2 distinct calls. In our choice of terms:

ttl are the minutes one ephid lasts before using the next
epoch is the count of ephids for the day (= (24*60) / ttl )