Matthias Gauger a écrit : > Hello Chao, > > On the one hand you want to avoid generating the same sequence of random > numbers each time you start your wireless sensor nodes and you want to > avoid predictability. On the other hand you want to reach a global > consensus among the nodes about the sequence of random numbers. > > Reaching the first goal should be possible with an external source of > randomness like used in TinyRNG. The second goal could be achieved by > using the same seed on all nodes for your RNG. Reaching both goals at > the same time sounds extremely hard. You are basically trying to solve > the consensus problem in distributed systems (with a particularly > difficult system model --> unreliable wireless sensor nodes)...
Well you could make this by modifying tinyrng : - deactivate the entropy collection - set the same inital seed for all nodes (by modifying TinyRNGSeeding) - adapt the initialization of TinyRNG in order to make it restart from previous state (by removing reinitialization step with state update) - check that at each new step you are saving the state (in order to restart from the same position in case of power failure), note that it's done right now with the eeprom and writing to the eeprom is extremely expensive in time/energy so be careful if you need random numbers often ... Time synchronization might be helpful too here ... Those are just hints... Cheers Aurélien _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
