PB-662 simplify pet messages

rust/src/lib.rs

@@ -1,7 +1,7 @@
 #![allow(dead_code)]
 #![allow(unused_imports)]
 #![feature(or_patterns)]
-#![feature(bool_to_option)]
+#![feature(const_fn)]
 
 #[macro_use]
 extern crate tracing;
@@ -15,10 +15,67 @@ pub mod participant;
 pub mod service;
 pub mod utils;
 
+use std::collections::HashMap;
+
+use sodiumoxide::crypto::{box_, sign};
+
 #[derive(Debug, PartialEq)]
+/// PET protocol errors.
 pub enum PetError {
  InsufficientSystemEntropy,
  InvalidMessage,
  InsufficientParticipants,
  AmbiguousMasks,
 }
+
+/// A public encryption key that identifies a coordinator.
+type CoordinatorPublicKey = box_::PublicKey;
+
+/// A secret encryption key that belongs to the public key of a coordinator.
+type CoordinatorSecretKey = box_::SecretKey;
+
+/// A public signature key that identifies a participant.
+type ParticipantPublicKey = sign::PublicKey;
+
+/// A secret signature key that belongs to the public key of a participant.
+type ParticipantSecretKey = sign::SecretKey;
+
+/// A public signature key that identifies a sum participant.
+type SumParticipantPublicKey = ParticipantPublicKey;
+
+/// A secret signature key that belongs to the public key of a sum participant.
+type SumParticipantSecretKey = ParticipantSecretKey;
+
+/// A public encryption key generated by a sum participant. It is used by the update participants to
+/// encrypt their masking seed for each sum participant.
+type SumParticipantEphemeralPublicKey = box_::PublicKey;
+
+/// A secret signature key that belongs to the public key of a sum participant.
+type SumParticipantEphemeralSecretKey = box_::SecretKey;
+
+/// A public signature key that identifies an update participant.
+type UpdateParticipantPublicKey = ParticipantPublicKey;
+
+/// A secret signature key that belongs to the public key of an update participant.
+type UpdateParticipantSecretKey = ParticipantSecretKey;
+
+/// A signature to prove a participant's elligibility for a task.
+type ParticipantTaskSignature = sign::Signature;
+
+/// A dictionary created during the sum phase of the protocol. It maps the public key of every sum
+/// participant to the ephemeral public key generated by that sum participant.
+type SumDict = HashMap<SumParticipantPublicKey, SumParticipantEphemeralPublicKey>;
+
+/// Local seed dictionaries are sent by update participants. They contain the participant's masking
+/// seed, encrypted with the ephemeral public key of each sum participant.
+type LocalSeedDict = HashMap<SumParticipantPublicKey, EncryptedMaskingSeed>;
+
+/// A dictionary created during the update phase of the protocol. The global seed dictionary is
+/// built from the local seed dictionaries sent by the update participants. It maps each sum
+/// participant to the encrypted masking seeds of all the update participants.
+type SeedDict =
+ HashMap<SumParticipantPublicKey, HashMap<UpdateParticipantPublicKey, EncryptedMaskingSeed>>;
+
+/// Masking seed generated by an update participant, encrypted with the ephemeral public key of a
+/// sum participant.
+type EncryptedMaskingSeed = Vec<u8>;