Efficient Fully Secure Computation via Distributed Zero-Knowledge Proofs

2020 ◽  
pp. 244-276
Author(s):  
Elette Boyle ◽  
Niv Gilboa ◽  
Yuval Ishai ◽  
Ariel Nof
Keyword(s):  
Secure Computation ◽  
Zero Knowledge

scholarly journals CacheQuote: Efficiently Recovering Long-term Secrets of SGX EPID via Cache Attacks

2018 ◽  
pp. 171-191 ◽  
Author(s):  
Fergus Dall ◽  
Gabrielle De Micheli ◽  
Thomas Eisenbarth ◽  
Daniel Genkin ◽  
Nadia Heninger ◽  
...  
Keyword(s):  
Secure Computation ◽  
Side Channel ◽  
Zero Knowledge ◽  
Signature Schemes ◽  
Number Problem ◽  
Trusted Hardware ◽  
Hidden Number Problem ◽  
Cache Attacks ◽  
Zero Knowledge Proof

Intel Software Guard Extensions (SGX) allows users to perform secure computation on platforms that run untrusted software. To validate that the computation is correctly initialized and that it executes on trusted hardware, SGX supports attestation providers that can vouch for the user’s computation. Communication with these attestation providers is based on the Extended Privacy ID (EPID) protocol, which not only validates the computation but is also designed to maintain the user’s privacy. In particular, EPID is designed to ensure that the attestation provider is unable to identify the host on which the computation executes. In this work we investigate the security of the Intel implementation of the EPID protocol. We identify an implementation weakness that leaks information via a cache side channel. We show that a malicious attestation provider can use the leaked information to break the unlinkability guarantees of EPID. We analyze the leaked information using a lattice-based approach for solving the hidden number problem, which we adapt to the zero-knowledge proof in the EPID scheme, extending prior attacks on signature schemes.

Efficient protocols for oblivious linear function evaluation from ring-LWE1

2021 ◽  
pp. 1-40
Author(s):  
Carsten Baum ◽  
Daniel Escudero ◽  
Alberto Pedrouzo-Ulloa ◽  
Peter Scholl ◽  
Juan Ramón Troncoso-Pastoriza
Keyword(s):  
Linear Function ◽  
Communication Complexity ◽  
General Purpose ◽  
Secure Computation ◽  
Function Evaluation ◽  
Zero Knowledge ◽  
Evaluation Protocol ◽  
Set Intersection ◽  
Secure Protocols ◽  
Learning With Errors

An oblivious linear function evaluation protocol, or OLE, is a two-party protocol for the function f ( x ) = a x + b, where a sender inputs the field elements a, b, and a receiver inputs x and learns f ( x ). OLE can be used to build secret-shared multiplication, and is an essential component of many secure computation applications including general-purpose multi-party computation, private set intersection and more. In this work, we present several efficient OLE protocols from the ring learning with errors (RLWE) assumption. Technically, we build two new passively secure protocols, which build upon recent advances in homomorphic secret sharing from (R)LWE (Boyle et al. in: EUROCRYPT 2019, Part II (2019) 3–33 Springer), with optimizations tailored to the setting of OLE. We upgrade these to active security using efficient amortized zero-knowledge techniques for lattice relations (Baum et al. in: CRYPTO 2018, Part II (2018) 669–699 Springer), and design new variants of zero-knowledge arguments that are necessary for some of our constructions. Our protocols offer several advantages over existing constructions. Firstly, they have the lowest communication complexity amongst previous, practical protocols from RLWE and other assumptions; secondly, they are conceptually very simple, and have just one round of interaction for the case of OLE where b is randomly chosen. We demonstrate this with an implementation of one of our passively secure protocols, which can perform more than 1 million OLEs per second over the ring Z m , for a 120-bit modulus m, on standard hardware.

Unconditionally Secure Computation with Reduced Interaction

2016 ◽  
pp. 420-447 ◽  
Author(s):  
Ivan Damgård ◽  
Jesper Buus Nielsen ◽  
Rafail Ostrovsky ◽  
Adi Rosén
Keyword(s):  
Secure Computation

Publicly auditable conditional blind signatures

2021 ◽  
Vol 29 (2) ◽  
pp. 229-271
Author(s):  
Panagiotis Grontas ◽  
Aris Pagourtzis ◽  
Alexandros Zacharakis ◽  
Bingsheng Zhang
Keyword(s):  
Proof Of Concept ◽  
Equivalence Test ◽  
Zero Knowledge ◽  
Private Key ◽  
Blind Signatures ◽  
Cryptographic Primitive ◽  
Security Properties ◽  
Designated Verifier

This work formalizes Publicly Auditable Conditional Blind Signatures (PACBS), a new cryptographic primitive that allows the verifiable issuance of blind signatures, the validity of which is contingent upon a predicate and decided by a designated verifier. In particular, when a user requests the signing of a message, blinded to protect her privacy, the signer embeds data in the signature that makes it valid if and only if a condition holds. A verifier, identified by a private key, can check the signature and learn the value of the predicate. Auditability mechanisms in the form of non-interactive zero-knowledge proofs are provided, so that a cheating signer cannot issue arbitrary signatures and a cheating verifier cannot ignore the embedded condition. The security properties of this new primitive are defined using cryptographic games. A proof-of-concept construction, based on the Okamoto–Schnorr blind signatures infused with a plaintext equivalence test is presented and its security is analyzed.

scholarly journals An access control model for the Internet of Things based on zero-knowledge token and blockchain

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Lihua Song ◽  
Xinran Ju ◽  
Zongke Zhu ◽  
Mengchen Li
Keyword(s):  
Internet Of Things ◽  
Access Control ◽  
Single Point ◽  
Control Model ◽  
Third Party ◽  
Security Level ◽  
Zero Knowledge ◽  
Access Control Model ◽  
Test Analysis ◽  
Zero Knowledge Proof

AbstractInformation security has become a hot topic in Internet of Things (IoT), and traditional centralized access control models are faced with threats such as single point failure, internal attack, and central leak. In this paper, we propose a model to improve the access control security of the IoT, which is based on zero-knowledge proof and smart contract technology in the blockchain. Firstly, we deploy attribute information of access control in the blockchain, which relieves the pressure and credibility problem brought by the third-party information concentration. Secondly, encrypted access control token is used to gain the access permission of the resources, which makes the user's identity invisible and effectively avoids attribute ownership exposure problem. Besides, the use of smart contracts solves the problem of low computing efficiency of IoT devices and the waste of blockchain computing power resources. Finally, a prototype of IoT access control system based on blockchain and zero-knowledge proof technology is implemented. The test analysis results show that the model achieves effective attribute privacy protection, compared with the Attribute-Based Access Control model of the same security level, the access efficiency increases linearly with the increase of access scale.

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