Struct RoastCoordinator 

pub struct RoastCoordinator {
    pub threshold: usize,
    pub pubkey_package: PublicKeyPackage,
    pub message: Vec<u8>,
    pub responsive_signers: BTreeSet<Identifier>,
    pub commitment_queues: BTreeMap<Identifier, VecDeque<(NonceSlotId, SigningCommitments)>>,
    pub active_sessions: BTreeMap<u128, RoastSession>,
    pub signer_to_session: BTreeMap<Identifier, u128>,
    pub banished_signers: BTreeSet<Identifier>,
    /* private fields */
}

ROAST Coordinator (Ruffing et al., CCS 2022) wrapping preprocessed FROST(Ed25519, SHA-512). Automatically spawns parallel sessions with available signers so up to n-t stalling or malicious signers cannot delay certificate issuance.

Fields

threshold: usize

pubkey_package: PublicKeyPackage

message: Vec<u8>

responsive_signers: BTreeSet<Identifier>

Signers currently available (not busy in an in-flight session).

commitment_queues: BTreeMap<Identifier, VecDeque<(NonceSlotId, SigningCommitments)>>

Preprocessed commitments per signer.

active_sessions: BTreeMap<u128, RoastSession>

Active concurrent sessions.

signer_to_session: BTreeMap<Identifier, u128>

Maps a busy signer to the session_id it is currently serving.

banished_signers: BTreeSet<Identifier>

Malicious signers detected via verify_signature_share failure.

Implementations

impl RoastCoordinator

pub fn new( threshold: usize, pubkey_package: PublicKeyPackage, message: Vec<u8>, ) -> Self

Creates a fresh ROAST coordinator for a target message buffer.

pub fn register_commitments( &mut self, signer_id: Identifier, commitments: Vec<(NonceSlotId, SigningCommitments)>, )

Registers a batch of preprocessed commitments from a signer and marks it responsive.

pub fn try_spawn_session( &mut self, ) -> Option<(u128, SigningPackage, BTreeMap<Identifier, NonceSlotId>)>

Attempts to spawn a new parallel FROST session if responsive_signers has at least threshold signers with available preprocessed commitments.

pub fn receive_share( &mut self, session_id: u128, signer_id: Identifier, share: SignatureShare, replenish: Option<(NonceSlotId, SigningCommitments)>, ) -> Result<Option<Signature>, Error>

Receives and verifies a partial SignatureShare from signer_id. Immediately isolates culprits via verify_signature_share, returns honest signers to the responsive pool, and completes signing as soon as any session gathers threshold shares.