TY - GEN
T1 - Secure source coding with a helper
AU - Tandon, Ravi
AU - Ulukus, Sennur
AU - Ramchandran, Kannan
PY - 2009
Y1 - 2009
N2 - We consider a secure lossless source coding problem with a rate-limited helper. In particular, Alice observes an i.i.d. source Xn and wishes to transmit this source losslessly to Bob at a rate Rx. A helper, say Helen, observes a correlated source Yn and transmits at a rate Ry to Bob. A passive eavesdropper can observe the coded output of Alice. The equivocation Δ is measured by the conditional entropy H(X n|Jx)/n, where Jx is the coded output of Alice. We first completely characterize the rate-equivocation region for this secure source coding model, where we show that Slepian-Wolf type coding is optimal. We next study two generalizations of this model and provide single-letter characterizations for the respective rateequivocation regions. In particular, we first consider the case of a two-sided helper where Alice also has access to the coded output of Helen. We show that for this case, Slepian-Wolf type coding is suboptimal and one can further decrease the information leakage to the eavesdropper by utilizing the sideinformation at Alice. We finally generalize this result to the case when there are both secure and insecure rate-limited links from Helen and additional uncoded side informations Wn and Zn available at Bob and Eve, respectively. For this model, we provide a complete characterization of the rate-equivocation region when Yn → Xn → (Wn,Zn) forms a Markov chain.
AB - We consider a secure lossless source coding problem with a rate-limited helper. In particular, Alice observes an i.i.d. source Xn and wishes to transmit this source losslessly to Bob at a rate Rx. A helper, say Helen, observes a correlated source Yn and transmits at a rate Ry to Bob. A passive eavesdropper can observe the coded output of Alice. The equivocation Δ is measured by the conditional entropy H(X n|Jx)/n, where Jx is the coded output of Alice. We first completely characterize the rate-equivocation region for this secure source coding model, where we show that Slepian-Wolf type coding is optimal. We next study two generalizations of this model and provide single-letter characterizations for the respective rateequivocation regions. In particular, we first consider the case of a two-sided helper where Alice also has access to the coded output of Helen. We show that for this case, Slepian-Wolf type coding is suboptimal and one can further decrease the information leakage to the eavesdropper by utilizing the sideinformation at Alice. We finally generalize this result to the case when there are both secure and insecure rate-limited links from Helen and additional uncoded side informations Wn and Zn available at Bob and Eve, respectively. For this model, we provide a complete characterization of the rate-equivocation region when Yn → Xn → (Wn,Zn) forms a Markov chain.
UR - http://www.scopus.com/inward/record.url?scp=77949627434&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77949627434&partnerID=8YFLogxK
U2 - 10.1109/ALLERTON.2009.5394875
DO - 10.1109/ALLERTON.2009.5394875
M3 - Conference contribution
AN - SCOPUS:77949627434
SN - 9781424458714
T3 - 2009 47th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2009
SP - 1061
EP - 1068
BT - 2009 47th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2009
T2 - 2009 47th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2009
Y2 - 30 September 2009 through 2 October 2009
ER -