TY - GEN
T1 - Computational Wiretap Coding from Indistinguishability Obfuscation
AU - Ishai, Yuval
AU - Jain, Aayush
AU - Lou, Paul
AU - Sahai, Amit
AU - Zhandry, Mark
N1 - Publisher Copyright:
© 2023, International Association for Cryptologic Research.
PY - 2023
Y1 - 2023
N2 - A wiretap coding scheme for a pair of noisy channels (ChB, ChE) enables Alice to reliably communicate a message to Bob by sending its encoding over ChB, while hiding the message from an adversary Eve who obtains the same encoding over ChE. A necessary condition for the feasibility of wiretap coding is that ChB is not a degradation of ChE, namely Eve cannot simulate Bob’s view. While insufficient in the information-theoretic setting, a recent work of Ishai, Korb, Lou, and Sahai (Crypto 2022) showed that the non-degradation condition is sufficient in the computational setting, assuming idealized flavors of obfuscation. The question of basing a similar feasibility result on standard cryptographic assumptions was left open, even in simple special cases. In this work, we settle the question for all discrete memoryless channels where the (common) input alphabet of ChB and ChE is binary, and with arbitrary finite output alphabet, under standard (sub-exponential) hardness assumptions: namely those assumptions that imply indistinguishability obfuscation (Jain-Lin-Sahai 2021, 2022), and injective PRGs. In particular, this establishes the feasibility of computational wiretap coding when ChB is a binary symmetric channel with crossover probability p and ChE is a binary erasure channel with erasure probability e, where e> 2 p. On the information-theoretic side, our result builds on a new polytope characterization of channel degradation for pairs of binary-input channels, which may be of independent interest.
AB - A wiretap coding scheme for a pair of noisy channels (ChB, ChE) enables Alice to reliably communicate a message to Bob by sending its encoding over ChB, while hiding the message from an adversary Eve who obtains the same encoding over ChE. A necessary condition for the feasibility of wiretap coding is that ChB is not a degradation of ChE, namely Eve cannot simulate Bob’s view. While insufficient in the information-theoretic setting, a recent work of Ishai, Korb, Lou, and Sahai (Crypto 2022) showed that the non-degradation condition is sufficient in the computational setting, assuming idealized flavors of obfuscation. The question of basing a similar feasibility result on standard cryptographic assumptions was left open, even in simple special cases. In this work, we settle the question for all discrete memoryless channels where the (common) input alphabet of ChB and ChE is binary, and with arbitrary finite output alphabet, under standard (sub-exponential) hardness assumptions: namely those assumptions that imply indistinguishability obfuscation (Jain-Lin-Sahai 2021, 2022), and injective PRGs. In particular, this establishes the feasibility of computational wiretap coding when ChB is a binary symmetric channel with crossover probability p and ChE is a binary erasure channel with erasure probability e, where e> 2 p. On the information-theoretic side, our result builds on a new polytope characterization of channel degradation for pairs of binary-input channels, which may be of independent interest.
UR - http://www.scopus.com/inward/record.url?scp=85173024308&partnerID=8YFLogxK
U2 - 10.1007/978-3-031-38551-3_9
DO - 10.1007/978-3-031-38551-3_9
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AN - SCOPUS:85173024308
SN - 9783031385506
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 263
EP - 293
BT - Advances in Cryptology – CRYPTO 2023 - 43rd Annual International Cryptology Conference, CRYPTO 2023, Proceedings
A2 - Handschuh, Helena
A2 - Lysyanskaya, Anna
T2 - Advances in Cryptology – CRYPTO 2023 - 43rd Annual International Cryptology Conference, CRYPTO 2023, Proceedings
Y2 - 20 August 2023 through 24 August 2023
ER -