Abstract:
Homomorphic encryption allows arithmetic operations
to be performed on ciphertext and gives the same result
as if the same arithmetic operation is done on the plaintext.
Homomorphic encryption has been touted as one of the promising
methods to be employed in Smart Grid (SG) to provide data
privacy which is one of the main security concerns in SG. In
addition to data privacy, real-time data flow is crucial in SG to
provide on-time detection and recovery of possible failures. In
this paper, we investigate the overhead of using homomorphic
encryption in SG in terms of bandwidth and end-to-end data
delay when providing data privacy. Specifically, we compare
the latency and data size of end-to-end (ETE) and hop-byhop
(HBH) homomorphic encryption within a network of Smart
Meters (SMs). In HBH encryption, at each intermediate node, the
received encrypted data from downstream nodes are decrypted
first before the aggregation, and then the result is encrypted again
for transmission to upstream nodes. On the other hand, the intermediate
node in ETE encryption only performs aggregation on
ciphertexts for transmission to upstream nodes. We implemented
secure data aggregation using Paillier cryptosystem and tested
it under various conditions. The experiment results have shown
that even though HBH homomorphic encryption has additional
computational overhead at intermediate nodes, surprisingly it
provides comparable latency and fixed data size passing through
the network compared to ETE homomorphic encryption.