mpc_engine/
messages.rs

1//! This module defines message types for the MPC protocol and its sub-protocols.
2use std::sync::mpsc::{Receiver, Sender};
3
4use crate::{
5    circuit::WireIndex,
6    primitives::{
7        auth_share::BitID,
8        commitment::{Commitment, Opening},
9        mac::Mac,
10        ot::{OTReceiverSelect, OTSenderInit, OTSenderSend},
11    },
12    COMPUTATIONAL_SECURITY,
13};
14
15/// An overall message type for all messages between parties.
16///
17/// It includes:
18/// - top-level protocol messages
19/// - suprotocol messages (incomplete)
20///   - messages for the FPre subprotocol
21///   - (not currently) messages for the remaining sub-protocols which implement
22///     FPre
23#[derive(Debug)]
24pub struct Message {
25    pub(crate) from: usize,
26    pub(crate) to: usize,
27    pub(crate) payload: MessagePayload,
28}
29
30/// Messages that are actually sent between parties in the top-level MPC
31/// protocol.
32#[derive(Debug)]
33pub enum MessagePayload {
34    /// A round synchronization message
35    Sync,
36    /// Request a number of bit authentications from another party.
37    RequestBitAuth(BitID, Sender<SubMessage>, Receiver<SubMessage>),
38    /// A response to a bit authentication request.
39    BitAuth(BitID, Mac),
40    /// A commitment on a broadcast value.
41    BroadcastCommitment(Commitment),
42    /// The opening to a broadcast value.
43    BroadcastOpening(Opening),
44    /// A subchannel for running an 2-party subprotocol.
45    SubChannel(Sender<SubMessage>, Receiver<SubMessage>),
46    /// A bit mac for validity checking
47    Mac(Mac),
48    /// Values sent over to other parties in the half-AND protocol
49    HalfAndHashes(bool, bool),
50    /// Value exchanged during leaky AND-triple check
51    LeakyAndU(Mac),
52    /// A two-party bit reveal message
53    BitReveal(bool, Mac),
54    /// A garbled AND gate, to be sent to the evaluator
55    GarbledAnd(Vec<u8>, Vec<u8>, Vec<u8>, Vec<u8>),
56    /// A MAC on a wire mask share
57    WireMac(bool, Mac),
58    /// Masked input wire value
59    MaskedInput(bool),
60    /// A wire label, to be sent to the evaluator
61    WireLabel {
62        /// The wire the label belongs to
63        wire: WireIndex,
64        /// The wire label
65        label: [u8; COMPUTATIONAL_SECURITY],
66    },
67}
68
69#[derive(Debug)]
70/// Message communicated on an subprotocol channel
71pub enum SubMessage {
72    /// An OT sender commitment
73    OTCommit(OTSenderInit),
74    /// An OT receiver selection
75    OTSelect(OTReceiverSelect),
76    /// An OT sender final message
77    OTSend(OTSenderSend),
78    /// An EQ initiator commitment
79    EQCommit(Commitment),
80    /// An EQ responder message
81    EQResponse(Vec<u8>),
82    /// An EQ initiator opening
83    EQOpening(Opening),
84}
mpc_engine/messages.rs

mpc_engine/
messages.rs
