Computer Security Resource Center

Computer Security Resource Center

Computer Security
Resource Center

Threshold Cryptography

Project Overview

The Computer Security Division at the National Institute of Standards and Technology is interested in promoting the security of implementations of cryptographic primitives. This security depends not only on the theoretical properties of the primitives but also on the ability to withstand attacks on their implementations. It is thus important to mitigate breakdowns that result from differences between ideal and real implementations of cryptographic algorithms.

This project focuses on threshold schemes for cryptographic primitives and their potential for strengthening the secrecy of cryptographic keys, as well as enhancing integrity and availability of implemented primitives, including providing resistance against side-channel attacks, which exploit inadvertent leakage from real implementations.

Background

At a basic level. classical secret sharing enables splitting the secret key into two or more shares across different components or parties, such that the compromise of one (or more, but not all) of the shares does not reveal information about the original key. Using appropriate threshold techniques, the shares can then be separately processed, leading the computation to a correct result as if the original secret key had been processed by a classic algorithm. The threshold approach can thus significantly increase the confidentiality of secret keys in cryptographic implementations.

Areas of relevant related research include secure multi-party computation, intrusion tolerant distributed systems, and threshold circuit design.

Tentative Plan

We published a draft report (Draft NISTIR 8214) to initiate a discussion on the standardization of threshold schemes for cryptographic primitives. The most immediate challenge going forward seems to be the development of criteria for and selection of proposals for standardization. The draft report motivated the need for criteria and developed some basis for it.

We intend to drive an open and transparent standardization process based on established NIST principles. We will incorporate the public comments to the draft report and plan to host a workshop in March 2019 to engage with the interested stakeholders on these topics. Once criteria are in place, the selection and standardization of concrete schemes should include considerations for the applicable validation methodologies.   

When tackling these challenges, positive synergies may result from engaging with and incorporating feedback from the research community, industry, government and other stakeholders.
 

Created July 26, 2018, Updated August 14, 2018