3 research outputs found
Secure Cascade Channel Synthesis
We consider the problem of generating correlated random variables in a
distributed fashion, where communication is constrained to a cascade network.
The first node in the cascade observes an i.i.d. sequence locally before
initiating communication along the cascade. All nodes share bits of common
randomness that are independent of . We consider secure synthesis - random
variables produced by the system appear to be appropriately correlated and
i.i.d. even to an eavesdropper who is cognizant of the communication
transmissions. We characterize the optimal tradeoff between the amount of
common randomness used and the required rates of communication. We find that
not only does common randomness help, its usage exceeds the communication rate
requirements. The most efficient scheme is based on a superposition codebook,
with the first node selecting messages for all downstream nodes. We also
provide a fleeting view of related problems, demonstrating how the optimal rate
region may shrink or expand.Comment: Submitted to IEEE Transactions on Information Theor