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	Succinct & verifiable-deterministic 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-QR blockcipher/PRP; TF-QR KC/KD	Encipher/decipher; PRF and hash function
C2.5: Keygen	Any of the above	Keygen
C2.6: Advanced	QR FHE; IBE; 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.