Privacy-Enhancing Cryptography

Privacy-Enhancing Cryptography PEC

Threshold schemes

The upcoming NIST First Call for Multi-Party Threshold Schemes (see the initial public draft in NIST IR8214C ipd) will solicit public proposals of threshold schemes (multi-party protocols) for various cryptographic primitives. This process involves techniques of MPC (secure multiparty computation), ZKP (zero-knowledge proofs), FHE (fully-homomorphic encryption), and IBE/ABE (identity-based and attribute-based encryption), among other techniques of interest to the PEC project. More details about the public call can be found in the webpage of the NIST Multi-Party Threshold Cryptography (MPTC) project.

Below is a copy of Table 2 of the mentioned draft call (NIST IR8214C ipd), showcasing the subcategories of interest, within category Cat2 (for primitives not specified by NIST). The analysis of submitted schemes will include engagement by the MPTC and the PEC projects.

Subcategory: Type

Example scheme

Example primitive

C2.1: Signing

TF Succinct & verifiable-deterministic signatures

Signing

TF-QR signatures

Signing

C2.2: PKE

TF-QR public-key encryption (PKE)

Decryption/encryption

C2.3: KA

Low-round multi-party key-agreement (KA)

Single-party primitives

C2.4: Symmetric

TF blockcipher/PRP

Encipher/decipher

TF key-derivation / key confirmation (KC)

PRF and hash function

C2.5: Keygen

Any of the above

Keygen

C2.6: Advanced

TF fully-homomorphic encryption (FHE)

Decryption; Keygens

TF identity-based encryption (IBE), attribute-based encryption (ABE)

Decryption; Keygens

C2.7: ZKPoK

ZKPoK of private key

ZKPoK.Generate

C2.8: Gadgets

Garbled circuit (GC)

GC.generate; GC.evaluate

Legend: 2KE = pair-wise key-establishment; KC = Key confirmation; KD = Key derivation; Keygen = key-generation; PRF = pseudorandom function (family); PRP = pseudorandom permutation (family); QR = quantum resistant; TF = threshold friendly; ZKPoK = Zero-knowledge proof of knowledge.