NIST Privacy-Enhancing Cryptography (PEC) Initiative - Threshold Call for Multi-Party Threshold Schemes, Category S6: Zero-Knowledge Proofs of Knowledge (ZKPoK)

NIST Privacy-Enhancing Cryptography (PEC) Initiative - Threshold Call for Multi-Party Threshold Schemes, Category S6: Zero-Knowledge Proofs of Knowledge (ZKPoK) is sponsored by National Institute of Standards and Technology (NIST). NIST seeks research proposals for standardizing zero-knowledge proofs of knowledge schemes under its PEC Initiative.

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gov . Information Technology Laboratory Computer Security Resource Center Privacy-Enhancing Cryptography PEC The PEC project in the Cryptographic Technology Group (CTG), Computer Security Division (CSD), Information Technology Laboratory (ITL), at NIST accompanies the progress of emerging technologies in the area of privacy-enhancing cryptography (PEC).

Upcoming events with available reference material: WPEC 2026 (2026-Oct-26–29): NIST Workshop on Privacy-Enhancing Cryptography Latest events with available reference material: MPTS 2026 (2026-Jan-26–29): Talks on MPC, FHE, ZKP. [ Slides ] STPPA #8 (2025-Sep-18): Talks on PSI, ZKP, and Threshold BLS Signatures. [ Slides ] STPPA #7 (2025-Jan-16) Talks on Timelock Encryption, Witness Encryption, and Deniable Encryption.

[ Slides ] WPEC 2024 (2024-Sep-24–26): NIST Workshop on Privacy-Enhancing Cryptography. [ Slides ] [ Videos ] The PEC project seeks to promote the development of reference material that can contribute to a better understanding of PEC, namely how advanced cryptographic tools can be used to enable achieving privacy goals in myriad applications.

A better understanding of PEC may facilitate the identification of cryptographic techniques whose possible standardization may be pertinent in the future. The technical challenge in PEC applications is often to enable parties to interact meaningfully, toward an application goal, without revealing extraneous private information to one another or to third parties.

(The "additional pages" linked on the right-side frame have further details about each activity area.) Workshops, Presentations and Discussions See detailed list in the pec/events page . STPPA (series of talks): In January of 2020, the PEC project initiated the " Special Topics on Privacy and Public Auditability " (STPPA) series of talks.

Each event includes various talks and a panel conversation on one or more topics related to PEC tools, and/or privacy and public auditability. The goal is to convey basic technical background, incite curiosity, suggest research questions, discuss applications, and gather reference material. See details in the pec/stppa page .

Event 08 (2025-Sep-18): PSI , ZKP , Threshold BLS Signatures Event 07 (2025-Jan-16): Timelock encryption , witness encryption , deniable encryption Event 06 (2023-Jul-25): community efforts: FHE , MPC , ZKP , ABE , CFRG , ISO-FHE Event 05 (2023-Feb-09): IBE , ABE , and broadcast encryption Event 04 (2022-Nov-21): anonymous credentials ( 1 , 2 ), blind signatures Event 03 (2021-Jul-06): PIR , encrypted search , FHE Event 02 (2021-Apr-19): PSI , MPC Event 01 (2020-Jan-27): public rand , differential privacy ( 1 , 2 ), video time-auth .

WPEC 2024 (Sep-24–26): The NIST Workshop on Privacy-Enhancing Cryptography) 2024 had 3 days devoted to PEC, including The First PSI Day, and other sessions on FHE, MPC and ZKP. [ Call for Talks ] [ Submission Form ] MPTS 2023 ( Sep-26 – 28): The NIST Workshop on Multi-Party Threshold Schemes) included one session (2a) dedicated to PEC tools. Before 2019.

Prior to the PEC project formalization (in 2019), PEC-related topics had already been considered by the following NIST workshops : 2011-Dec-08 – 09: A PEC meeting . 2011-Nov-07 – 08: CETA ( Workshop on C ryptography for E merging T echnologies and A pplications ). 2008-Jun-03 – 04: A workshop on crypto applications of pairings, including IBE .

CRClub: The NIST Crypto Reading Club also hosts some PEC-related talks (by external speakers). HES. HomomorphicEncryption.

org is an open initiative promoting the standardization of fully-homomorphic encryption (FHE), a technique of high interest to the PEC project. NIST-PEC participated with invited talks at the HES5 [ slides ] (Geneva, 2022), HES6 [ slides ] (South Korea, 2023) and HES7 [ slides ] (Salt Lake City, 2024) meetings.

(Prior to the PEC project, NIST was also present at HES1 (Redmond, 2017) , whose working group developed a community proposal of HE security standard ). See more documentation in the pec/fhe page. ZKProof.

ZKProof is an open initiative, of academia and industry, developing reference material to promote the secure, efficient and interoperable use of zero-knowledge-proofs technology. Since 2019, NIST-PEC has provided public feedback and collaborated in the development of reference material open to the public. See related documentation in the pec/zkproof page .

Privacy-related Strategies. The U.S. develops national strategies on important privacy-related topics. NIST-PEC participated in the writing teams of the National Strategy to Advance Privacy-Preserving Data Sharing and Analytics (2023), and the National Privacy Research Strategy (2025).

The upcoming NIST Call for Multi-Party Threshold Schemes (see the initial public draft in NIST IR8214C ipd ), jointly output by the multi-party threshold cryptography (MPTC) project and the privacy-enhancing cryptography (PEC) project , will solicit public proposals of threshold scheme (multi-party protocols) for various cryptographic primitives.

The process involves consideration of various cryptographic techniques of interest to the PEC project, including MPC ( s ecure m ultiparty c omputation), ZKP ( z ero- k nowledge p roofs), FHE ( f ully- h omomorphic e ncryption), and IBE/ABE ( i dentity- b ased and a ttribute- b ased e ncryption). See details in the pec/threshold page .

A PEC use-case suite would constitute a set of proofs of concepts, showcasing the use of cryptographic tools for enabling privacy in various applications. A preliminary draft is available (January 2021) to motivate initial public feedback. See details in the pec/suite page .

In our exploration of "privacy-enhancing cryptography" (PEC), we consider selected "PEC tools" as cryptographic primitives, techniques and protocols of interest to privacy-enhancing/preserving applications. These PEC tools can serve as enablers of responsible data sharing and interactions, in settings where otherwise (without PEC) one may lack trust to partake in such processes, or be unable to meet privacy regulatory requirements.

A blogpost published in the NIST differential privacy blog series illustrates at a high-level how some of these tools are distinct from (and may be used in complement to) differential privacy. Our pec/tools page displays an illustrated perspective of PEC tools based on (informal) "ideal functionalities".

The National Strategy to Advance Privacy Preserving Data Sharing and Analytics mentions various PEC tools, including secure multiparty computation, homomorphic encryption, and zero knowledge proofs.

Our pec/threshold page includes PEC-related details about the "NIST Call for Multi-Party Threshold Schemes" ( IR 8214C ), which considers multi-party computation (in the scope of "threshold cryptography") as the baseline paradigm to enable threshold schemes, and asks for submission of threshold schemes for various other PEC tools, such as ZKP, FHE, IBE and ABE.

The following table (adapted from the PEC use-case suite ) provides a succinct informal description of several relevant PEC tools. Description hint (informal) Z ero- k nowledge P roof (ZKP) Prove knowledge of a secret solution to a problem, without revealing the solution. ( S ecure) M ultiparty C omputation (MPC) Jointly compute a function over inputs distributed across several parties, without each party revealing their input.

F ully- H omomorphic E ncryption (FHE) Compute over encrypted data, without learning the plaintext in-put/output, but ensuring the intended functional transformation. F u n ctional e ncryption (FnE) Decrypt a function (as specified by a decryption key) of a plaintext that has been encrypted, without learning the clear plaintext. Specific cases of interest are identity-based encryption (IBE) and attribute based encryption (ABE).

G roup and r ing s ignatures (GRS) Produce an unforgeable digital signature, convincingly exhibiting that it has been signed by an unrevealed member of a group. P rivate S et I ntersection (PSI) Determine the intersection of sets held by multiple parties, without revealing the non-intersecting components.

P rivate I nformation R etrieval (PIR) Query a key-value database, with the database owner being assured that only one element was queried but not learning which. St ructured E ncryption (StE) Allows privately querying encrypted data structures, e.g., searching for a keyword in a database of encrypted documents, obtaining the resulting documents without revealing the keyword.

For example, z ero- k nowledge p roofs (ZKPs) allow one party (the prover) to prove to another party (the verifier) that a given statement is true and/or that the solution to some mathematical problem is known to the prover, without revealing any information about the solution itself.

More generally, s ecure m ulti p arty c omputation (SMPC or MPC) allows multiple parties, often mutually distrustful, to compute some property of their joint inputs, as if it were computed by a trusted third party. This means that the computation occurs without sharing inputs, and while ensuring correct outputs.

As another example, f ully h omomorphic e ncryption (FHE) allows performing computation on encrypted data without having to perform decryption, which in turn can be used to delegate computation to untrusted parties. Other PEC tools include group signatures, searchable encryption, private information retrieval, private set intersection and functional encryption.

Areas of interest for application of PEC include identification, authentication, statistics over distributed data, and public auditability, among many others. Here are a few examples: Minimum-disclosure credential: A person has a credential, issued and digitally signed by an authority, and containing private identifiable information (PII). The credential is used to prove some predicate P() on the PII (e.g., the person is of voting age).

We want to allow practical protocols by which only the predicate P() is revealed to a verifier. Brokered identification: Identity providers (IDPs) can enable users to authenticate to service providers (SPs). Some settings require a broker to mediate this transaction, to allow authentication of a passive user (not having any specialized software) between the IDP and SP, while blinding the IDP and SP from one another.

Using PEC, the user privacy can be preserved even with respect to the mediator. Students right to know: A U.S. congress bill proposes the use of SMPC to calculate, on behalf of students, the expected monetary return on the investment made on their college degrees. The data required to make this calculation is held by multiple sources.

Because of privacy concerns, these sources cannot simply release their data. Combining privacy and public auditability: The NIST Randomness Beacon publishes a random 512-bit number every minute. The numbers are signed by NIST, time-stamped, and chained into an immutable chain.

A trusted source of public randomness can help numerous parties to coordinate on future randomness to use, while also allowing post-facto public verification that correct randomness was used. Using PEC, e.g., zero-knowledge proofs, it is possible to allow such public auditability, while also satisfying privacy requirements. A more comprehensive list of examples will be compiled in the scope of the PEC use-case suite .

Feedback is appreciated. NIST privacy-related projects/programs Besides PEC (first row in the table below), NIST runs various other privacy-related project/programs, including those involving systems engineering, prize challenges, cybersecurity research, and collaborative events. The table below lists various examples.

Privacy-Enhancing Cryptography (PEC) An initiative of the NIST Cryptographic Technology Group, to develop reference material and prepare future guidance about advanced cryptographic tools (such as MPC, ZKP, FHE, PSI) that can be used for applications of privacy and public auditability.

Privacy Engineering Program (PEP) A NIST program to support the development of trustworthy information systems by creating frameworks, risk models, guidance, tools, and standards that protect privacy.

A tool to help organizations improve individuals' privacy through enterprise risk management PETS Prize Challenge (2022/2023) A privacy-enhancing technologies (PETs) prize challenge for Advancing Privacy-Preserving Federated Learning Differential Privacy Temporal Map Challenge (2020) A prize challenge on differential privacy (2020) The National Cybersecurity Center of Excellence develops various projects of interest to Privacy and Cybersecurity NIST Multi-Party Threshold Cryptograph y Establishes the NIST Threshold Call, to gather reference material on Threshold Cryptography, including related to Multi-Party Computation (MPC), Fully-Homomorphic Encryption (FHE), and Zero-Knowledge Proofs (ZKP), with high potential for enabling privacy-enhancing applications.

Collaborative Research Cycle Homepage Series of workshops on selected topics of privacy engineering Usable Cybersecurity program Research to improve the usability of privacy mechanisms The actual privacy terms related to interactions with NIST Fully-Homomorphic Encryption (FHE) Private Set Intersection (PSI) / Operations (PSO) Zero-Knowledge Proof (ZKP) Multi-Party Computation (MPC) and Threshold schemes Cryptographic Standards and Guidelines Multi-Party Threshold Cryptography Fully-Homomorphic Encryption (FHE) Private Set Intersection (PSI) / Operations (PSO) Zero-Knowledge Proof (ZKP) Multi-Party Computation (MPC) and Threshold schemes Cryptographic Standards and Guidelines Multi-Party Threshold Cryptography Created January 03, 2017 , Updated July 01, 2026