ZF FROST (Flexible Round-Optimised Schnorr Threshold signatures)

Crate		Crates.io	Documentation
Generic FROST implementation	[frost-core]
Ristretto255 ciphersuite	[frost-ristretto255]
Ed25519 ciphersuite	[frost-ed25519]
Ed448 ciphersuite	[frost-ed448]
P-256 ciphersuite	[frost-p256]
secp256k1 ciphersuite	[frost-secp256k1]
Generic Re-randomized FROST	[frost-rerandomized]

Rust implementations of 'Two-Round Threshold Schnorr Signatures with FROST'.

Unlike signatures in a single-party setting, threshold signatures require cooperation among a threshold number of signers, each holding a share of a common private key. The security of threshold schemes in general assume that an adversary can corrupt strictly fewer than a threshold number of participants.

'Two-Round Threshold Schnorr Signatures with FROST' presents a variant of a Flexible Round-Optimized Schnorr Threshold (FROST) signature scheme originally defined in FROST20. FROST reduces network overhead during threshold signing operations while employing a novel technique to protect against forgery attacks applicable to prior Schnorr-based threshold signature constructions.

Besides FROST itself, this repository also provides:

• Trusted dealer key generation as specified in the appendix of 'Two-Round Threshold Schnorr Signatures with FROST';
• Distributed key generation as specified in the original paper FROST20;
• Repairable Theshold Scheme (RTS) from 'A Survey and Refinement of Repairable Threshold Schemes' which allows a participant to recover a lost share with the help of a threshold of other participants;
• Rerandomized FROST (paper under review).

Getting Started

Refer to the ZF FROST book.

Status ⚠

The FROST specification is not yet finalized, though no significant changes are expected at this point. This code base has been audited by NCC. The APIs and types in frost-core are subject to change during the release candidate phase, and will follow SemVer guarantees after 1.0.0.

Usage

frost-core implements the base traits and types in a generic manner, to enable top-level implementations for different ciphersuites / curves without having to implement all of FROST from scratch. End-users should not use frost-core if they want to sign and verify signatures, they should use the crate specific to their ciphersuite/curve parameters that uses frost-core as a dependency.