Theory of cryptography : 18th International Conference, TCC 2020, Durham, NC, USA, November 16-19, 2020, Proceedings. Part I / Rafael Pass, Krzysztof Pietrzak (eds.).

International conference proceedings.

"TCC 2020 was originally planned to be co-located with FOCS 2020 in Durham, North Carolina, USA. Due to the COVID-19 pandemic both events were converted into virtual events, and were held on the same day at the same time."--Preface

Intro -- Preface -- Organization -- Contents -- Part I -- Contents -- Part II -- Contents -- Part III -- Lossiness and Entropic Hardness for Ring-LWE -- 1 Introduction -- 1.1 Our Results -- 1.2 Our Techniques -- 1.3 Paper Organization -- 2 Notation and Definitions -- 2.1 Min-Entropy -- 2.2 Leftover Hashing -- 2.3 Lattices and Gaussians -- 2.4 Noise Lossiness -- 2.5 Algebraic Number Fields -- 2.6 Ring-LWE -- 3 (Entropic) Structured LWE -- 3.1 Rerandomization -- 3.2 Ring-LWE as Structured LWE -- 4 Sometimes Lossiness and Hardness of Entropic Structured LWE

4.1 From Sometimes Lossiness to the Hardness of Entropic Structured LWE -- 5 Construction of Sometimes Lossy Distributions -- 6 Instantiation for RLWE over Power-of-Two Cyclotomics -- References -- Multi-key Fully-Homomorphic Encryption in the Plain Model -- 1 Introduction -- 1.1 Our Results -- 1.2 Open Problems -- 2 Technical Overview -- 2.1 Reusability Transformation -- 2.2 From pMHE to Multi-key FHE -- 2.3 From pMHE to MHE -- 2.4 Instantiating One-Time pMHE in the CRS Model -- 3 Preliminaries -- 3.1 Garbling Schemes -- 3.2 Laconic Function Evaluation -- 4 Multi-key Fully Homomorphic Encryption

5 Multiparty Homomorphic Encryption -- 5.1 Definition -- 5.2 Security -- 6 Intermediate Notion: MHE with Private Evaluation (pMHE) -- 6.1 CRS Model -- 6.2 One-Time pMHE -- 6.3 Ciphertext Succinctness -- 6.4 Instantiation -- 7 Main Step: One-Time pMHE in CRS -3mu Reusable pMHE -- 7.1 Correctness -- 7.2 Security -- 7.3 Instantiation -- 8 Result #1: Construction of Multi-key FHE -- 8.1 Instantiation -- 9 Result #2: Construction of MHE -- 9.1 Non-Succinct pMHE to Succinct pMHE -- 9.2 pMHE to MHE: Private to Public Evaluation -- References

Constant Ciphertext-Rate Non-committing Encryption from Standard Assumptions -- 1 Introduction -- 1.1 Our Results -- 1.2 Related Work -- 1.3 Discussion and Open Problems -- 2 Technical Overview -- 2.1 Packed Encryption with Equivocality -- 2.2 Construction from LWE -- 2.3 Construction from DDH -- 2.4 Construction from QR -- 3 Preliminaries -- 3.1 Coding Theory -- 3.2 Hardness Assumptions -- 3.3 Non-committing Encryption -- 4 Ciphertext Shrinking Algorithms -- 4.1 Ciphertext Shrinking Algorithm for LWE-Based Encryption Schemes -- 4.2 Ciphertext Shrinking Algorithm for DDH-Based Encryption Schemes

4.3 Ciphertext Shrinking Algorithm for QR-Based Encryption Schemes -- 5 Packed Encryption with Partial Equivocality -- 5.1 Packed Encryption with Partial Equivocality from LWE -- 5.2 Packed Encryption with Partial Equivocality from DDH -- 5.3 Packed Encryption with Partial Equivocality from QR -- 6 From PEPE to Constant Ciphertext-Rate NCE -- References -- Efficient Range-Trapdoor Functions and Applications: Rate-1 OT and More -- 1 Introduction -- 1.1 Our Results -- 1.2 Related Work and Open Problems -- 1.3 Technical Overview -- 2 Preliminaries -- 2.1 Standard Definitions and Lemmas

2.2 Computational Assumptions.

Includes author index.

This three-volume set, LNCS 12550, 12551, and 12552, constitutes the refereed proceedings of the 18th International Conference on Theory of Cryptography, TCCC 2020, held in Durham, NC, USA, in November 2020. The total of 71 full papers presented in this three-volume set was carefully reviewed and selected from 167 submissions. Amongst others they cover the following topics: study of known paradigms, approaches, and techniques, directed towards their better understanding and utilization; discovery of new paradigms, approaches and techniques that overcome limitations of the existing ones, formulation and treatment of new cryptographic problems; study of notions of security and relations among them; modeling and analysis of cryptographic algorithms; and study of the complexity assumptions used in cryptography. Due to the Corona pandemic this event was held virtually.

Online resource; title from PDF title page (SpringerLink, viewed February 17, 2021).