Struct SetupMessage

pub struct SetupMessage<SK = NoSigningKey, VK = NoVerifyingKey, MS = NoSignature, KS = Keyshare, PK = ProjectivePoint> { /* private fields */ }

A message used for setting up quorum changes in a multi-party computation protocol.

This struct encapsulates all necessary information for changing the quorum of participants, including old and new participant information, cryptographic keys, and protocol parameters.

Type Parameters

• SK - The type of signing key used for message signatures
• VK - The type of verifying key used to verify message signatures
• MS - The type of message signature
• KS - The type of keyshare used in the protocol
• PK - The type of public key used in the protocol

Implementations

impl<SK, VK, MS, KS, PK> SetupMessage<SK, VK, MS, KS, PK>

pub fn new( instance: InstanceId, this_party: usize, old_parties: &[usize], new_parties: &[(usize, u8)], new_t: usize, sk: SK, vk: Vec<VK>, public_key: PK, ) -> Self

Creates a new setup message for quorum changes.

Arguments

• instance - Instance identifier for the protocol
• this_party - ID of the current party
• old_parties - Indices of old participants
• new_parties - Pairs of (index, rank) for new participants
• new_t - New threshold value
• sk - Signing key for the current party
• vk - Vector of verifying keys for all participants
• public_key - Public key for the protocol

Panics

Panics if:

• this_party is not less than the total number of parties
• Any old party index is not less than the total number of parties
• Any new party index is not less than the total number of parties
• new_t is greater than the number of new parties

pub fn with_ttl(self, ttl: Duration) -> Self

Sets a custom time-to-live duration for messages.

Arguments

• ttl - The new time-to-live duration

Returns

The modified SetupMessage instance

pub fn with_keyshare_opt(self, keyshare: Option<Arc<KS>>) -> Self

Sets an optional keyshare for the protocol.

Arguments

• keyshare - Optional reference to the keyshare

Returns

The modified SetupMessage instance

pub fn with_keyshare(self, keyshare: Arc<KS>) -> Self

Sets a keyshare for the protocol.

Arguments

• keyshare - Reference to the keyshare

Returns

The modified SetupMessage instance

Trait Implementations

impl<SK, VK, MS, KS, PK> ProtocolParticipant for SetupMessage<SK, VK, MS, KS, PK>

where SK: Signer<MS>, MS: SignatureEncoding, VK: AsRef<[u8]> + Verifier<MS>,

fn signer(&self) -> &Self::MessageSigner

Returns the signing key for the current participant.

fn verifier(&self, index: usize) -> &Self::MessageVerifier

Returns the verifying key for a specific participant.

Arguments

• index - The index of the participant

Returns

A reference to the verifying key

fn instance_id(&self) -> &InstanceId

Returns the instance identifier for the protocol.

fn message_ttl(&self) -> Duration

Returns the time-to-live duration for messages.

fn participant_index(&self) -> usize

Returns the index of the current participant.

fn total_participants(&self) -> usize

Returns the total number of participants in the protocol.

type MessageSignature = MS

Type of a signature, added at end of all broadcast messages passed between participants.

type MessageSigner = SK

Type to sign broadcast messages, some kind of SecretKey.

type MessageVerifier = VK

Type to verify signed message, a verifying key. AsRef<u8> is used to get external representation of the key to derive message ID.

fn participant_verifier(&self) -> &Self::MessageVerifier

Return reference to participant’s own verifier

fn all_other_parties(&self) -> AllOtherParties

Return iterator of all participant’s indexes except own one.

fn msg_id(&self, receiver: Option<usize>, tag: MessageTag) -> MsgId

Generate ID of a message from this party to some other (or broadcast) if passed receiver is None.

fn msg_id_from( &self, sender: usize, receiver: Option<usize>, tag: MessageTag, ) -> MsgId

Generate ID of a message from given sender to a given receiver. Receiver is designed by its index and is None for a broadcase message.

impl<SK, VK, MS, KS, PK> QuorumChangeSetupMessage<KS, PK> for SetupMessage<SK, VK, MS, KS, PK>

where SK: Signer<MS>, MS: SignatureEncoding, VK: AsRef<[u8]> + Verifier<MS>,

fn old_keyshare(&self) -> Option<&KS>

Returns a reference to the old keyshare if it exists.

fn new_threshold(&self) -> u8

Returns the new threshold value for the protocol.

fn new_participant_rank(&self, party_id: u8) -> u8

Returns the rank of a specific participant in the new quorum.

Arguments

• party_id - The ID of the participant

Returns

The rank of the participant

fn expected_public_key(&self) -> &PK

Returns the expected public key for the protocol.

fn old_party_indices(&self) -> &[usize]

Returns the indices of the old participants.

fn new_party_indices(&self) -> &[usize]

Returns the indices of the new participants.

fn derive_key_id(&self, public_key: &[u8]) -> [u8; 32]

Derives a key identifier from a public key.

This is a trivial implementation that takes the first 32 bytes of the public key.

Arguments

• public_key - The public key to derive the identifier from

Returns

A 32-byte key identifier

fn new_party_id(&self, index: usize) -> Option<u8>

return new_party_id by party_index

fn keyshare_extra(&self) -> &[u8]

Additional data to incorpatate into resulting Keyshare.