Composable Adaptive Secure Protocols without Setup under Polytime Assumptions

All previous constructions of general multiparty computation protocols that are secure against adaptive corruptions in the concurrent setting either require some form of setup or non-standard assumptions. In this paper we provide the first general construction of secure multi-party computation protocol without any setup that guarantees composable security in the presence of an adaptive adversary based on standard polynomial-time assumptions. We prove security under the notion of ``UC with super-polynomial helpers\u27\u27 introduced by Canetti et al. (FOCS 2010), which is closed under universal composition and implies ``super-polynomial-time simulation\u27\u27. Moreover, our construction relies on the underlying cryptographic primitives in a black-box manner. Next, we revisit the zero-one law for two-party secure functions evaluation initiated by the work of Maji, Prabhakaran and Rosulek (CRYPTO 2010). According to this law, every two-party functionality is either trivial (meaning, such functionalities can be reduced to any other functionality) or complete (meaning, any other functionality can be reduced to these functionalities) in the Universal Composability (UC) framework. As our second contribution, assuming the existence of a simulatable public-key encryption scheme, we establish a zero-one law in the adaptive setting. Our result implies that every two-party non-reactive functionality is either trivial or complete in the UC framework in the presence of adaptive, malicious adversaries

Theory of Cryptography [electronic resource] : 14th International Conference, TCC 2016-B, Beijing, China, October 31-November 3, 2016, Proceedings, Part I /

The two-volume set LNCS 9985 and LNCS 9986 constitutes the refereed proceedings of the 14th International Conference on Theory of Cryptography, TCC 2016-B, held in Beijing, China, in November 2016. The total of 45 revised full papers presented in the proceedings were carefully reviewed and selected from 113 submissions. The papers were organized in topical sections named: TCC test-of-time award; foundations; unconditional security; foundations of multi-party protocols; round complexity and efficiency of multi-party computation; differential privacy; delegation and IP; public-key encryption; obfuscation and multilinear maps; attribute-based encryption; functional encryption; secret sharing; new models.TCC Test-of-Time Award -- From Indifferentiability to Constructive Cryptography (and Back) -- Foundations -- Fast Pseudorandom Functions Based on Expander Graphs -- 3-Message Zero Knowledge Against Human Ignorance -- The GGM Function Family is a Weakly One-Way Family of Functions -- On the (In)security of SNARKs in the Presence of Oracles -- Leakage Resilient One-Way Functions: The Auxiliary-Input Setting -- Simulating Auxiliary Inputs, Revisited -- Unconditional Security -- Pseudoentropy: Lower-bounds for Chain rules and Transformations -- Oblivious Transfer from Any Non-Trivial Elastic Noisy Channel via Secret Key Agreement -- Simultaneous Secrecy and Reliability Amplification for a General Channel Model -- Proof of Space from Stacked Expanders -- Perfectly Secure Message Transmission in Two Rounds -- Foundations of Multi-Party Protocols -- Almost-Optimally Fair Multiparty Coin-Tossing with Nearly Three-Quarters Malicious -- Binary AMD Circuits from Secure Multiparty Computation -- Composable Security in the Tamper-Proof Hardware Model under Minimal Complexity -- Composable Adaptive Secure Protocols without Setup under Polytime Assumptions -- Adaptive Security of Yao’s Garbled Circuits -- Round Complexity and Efficiency of Multi-Party Computation -- Efficient Secure Multiparty Computation with Identifiable Abort -- Secure Multiparty RAM Computation in Constant Rounds -- Constant-Round Maliciously Secure Two-Party Computation in the RAM Model -- More Efficient Constant-Round Multi-Party Computation from BMR and SHE -- Cross&Clean: Amortized Garbled Circuits With Constant Overhead -- Differential Privacy -- Separating Computational and Statistical Differential Privacy in the Client-Server Model -- Concentrated Differential Privacy: Simplifications, Extensions, and Lower Bounds -- Strong Hardness of Privacy from Weak Traitor Tracing. .The two-volume set LNCS 9985 and LNCS 9986 constitutes the refereed proceedings of the 14th International Conference on Theory of Cryptography, TCC 2016-B, held in Beijing, China, in November 2016. The total of 45 revised full papers presented in the proceedings were carefully reviewed and selected from 113 submissions. The papers were organized in topical sections named: TCC test-of-time award; foundations; unconditional security; foundations of multi-party protocols; round complexity and efficiency of multi-party computation; differential privacy; delegation and IP; public-key encryption; obfuscation and multilinear maps; attribute-based encryption; functional encryption; secret sharing; new models