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Align protocol with specs
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‎cggmp21/src/signing.rs

+58-75
Original file line numberDiff line numberDiff line change
@@ -363,7 +363,7 @@ where
363363
.map_err(SigningError::ReceiveMessage)?;
364364
self.tracer.msgs_received();
365365

366-
// Ensure reliability of round1a: broadcast hash(ciphertexts)
366+
// Step 1. Ensure reliability of round1a: broadcast hash(ciphertexts)
367367
self.tracer.stage("Hash received msgs (reliability check)");
368368
let ciphertexts_hash = ciphertexts
369369
.iter_including_me(&MsgRound1a {
@@ -383,7 +383,7 @@ where
383383
.map_err(SigningError::SendError)?;
384384
self.tracer.msg_sent();
385385

386-
// Step 1. Verify proofs
386+
// Step 2. Verify proofs
387387
self.tracer.stage("Verify ψ0 proofs");
388388
{
389389
let mut faulty_parties = vec![];
@@ -414,29 +414,7 @@ where
414414
}
415415
}
416416

417-
// Ensure reliability of round1a: receive hash(ciphertexts) from others
418-
{
419-
self.tracer.receive_msgs();
420-
let round1a_hashes = rounds
421-
.complete(round1a_sync)
422-
.await
423-
.map_err(SigningError::ReceiveMessage)?;
424-
self.tracer.msgs_received();
425-
self.tracer
426-
.stage("Assert other parties hashed messages (reliability check)");
427-
let parties_have_different_hashes = round1a_hashes
428-
.into_iter_indexed()
429-
.filter(|(_j, _msg_id, hash)| hash.0 != ciphertexts_hash)
430-
.map(|(j, msg_id, _)| (j, msg_id))
431-
.collect::<Vec<_>>();
432-
if !parties_have_different_hashes.is_empty() {
433-
return Err(
434-
SigningAborted::Round1aNotReliable(parties_have_different_hashes).into(),
435-
);
436-
}
437-
}
438-
439-
// Step 2
417+
// Step 3
440418
let Γ_i = Point::generator() * &y_i;
441419
let J = BigNumber::one() << (L::ELL_PRIME + 1);
442420

@@ -589,7 +567,29 @@ where
589567
// Round 3
590568
self.tracer.round_begins();
591569

592-
// Step 1
570+
// Step 1. Ensure reliability of round1a: receive hash(ciphertexts) from others
571+
{
572+
self.tracer.receive_msgs();
573+
let round1a_hashes = rounds
574+
.complete(round1a_sync)
575+
.await
576+
.map_err(SigningError::ReceiveMessage)?;
577+
self.tracer.msgs_received();
578+
self.tracer
579+
.stage("Assert other parties hashed messages (reliability check)");
580+
let parties_have_different_hashes = round1a_hashes
581+
.into_iter_indexed()
582+
.filter(|(_j, _msg_id, hash)| hash.0 != ciphertexts_hash)
583+
.map(|(j, msg_id, _)| (j, msg_id))
584+
.collect::<Vec<_>>();
585+
if !parties_have_different_hashes.is_empty() {
586+
return Err(
587+
SigningAborted::Round1aNotReliable(parties_have_different_hashes).into(),
588+
);
589+
}
590+
}
591+
592+
// Step 2
593593
self.tracer.receive_msgs();
594594
let round2_msgs = rounds
595595
.complete(round2)
@@ -607,69 +607,56 @@ where
607607
let enc_j = encryption_key_from_n(&aux_j.N);
608608

609609
self.tracer.stage("Validate ψ");
610-
let ψ_invalid = {
611-
let data = π_aff::Data {
610+
let ψ_invalid = π_aff::non_interactive::verify(
611+
parties_shared_state.clone(),
612+
&aux_i.into(),
613+
&π_aff::Data {
612614
key0: enc_i.clone(),
613615
key1: enc_j.clone(),
614-
// c: msg.D.clone(),
615-
// d: K_i.clone(),
616616
c: K_i.clone(),
617617
d: msg.D.clone(),
618618
y: msg.F.clone(),
619619
x: msg.Γ,
620-
};
621-
π_aff::non_interactive::verify(
622-
parties_shared_state.clone(),
623-
&aux_i.into(),
624-
&data,
625-
&msg.ψ.0,
626-
&security_params.π_aff,
627-
&msg.ψ.1,
628-
)
629-
.err()
630-
};
620+
},
621+
&msg.ψ.0,
622+
&security_params.π_aff,
623+
&msg.ψ.1,
624+
)
625+
.err();
631626

632627
self.tracer.stage("Validate ψˆ");
633-
let ψˆ_invalid = {
634-
let data = π_aff::Data {
628+
let ψˆ_invalid = π_aff::non_interactive::verify(
629+
parties_shared_state.clone(),
630+
&aux_i.into(),
631+
&π_aff::Data {
635632
key0: enc_i.clone(),
636633
key1: enc_j.clone(),
637-
// c: msg.Dˆ.clone(),
638-
// d: K_i.clone(),
639634
c: K_i.clone(),
640635
d: msg.Dˆ.clone(),
641636
y: msg.Fˆ.clone(),
642637
x: X_j,
643-
};
644-
π_aff::non_interactive::verify(
645-
parties_shared_state.clone(),
646-
&aux_i.into(),
647-
&data,
648-
&msg.ψˆ.0,
649-
&security_params.π_aff,
650-
&msg.ψˆ.1,
651-
)
652-
.err()
653-
};
638+
},
639+
&msg.ψˆ.0,
640+
&security_params.π_aff,
641+
&msg.ψˆ.1,
642+
)
643+
.err();
654644

655645
self.tracer.stage("Validate ψ_prime");
656-
let ψ_prime_invalid = {
657-
let data = π_log::Data {
646+
let ψ_prime_invalid = π_log::non_interactive::verify(
647+
parties_shared_state.clone(),
648+
&aux_i.into(),
649+
&π_log::Data {
658650
key0: enc_j.clone(),
659651
c: ciphertexts.G.clone(),
660652
x: msg.Γ,
661653
g: Point::<E>::generator().to_point(),
662-
};
663-
π_log::non_interactive::verify(
664-
parties_shared_state.clone(),
665-
&aux_i.into(),
666-
&data,
667-
&msg.ψ_prime.0,
668-
&security_params.π_log,
669-
&msg.ψ_prime.1,
670-
)
671-
.err()
672-
};
654+
},
655+
&msg.ψ_prime.0,
656+
&security_params.π_log,
657+
&msg.ψ_prime.1,
658+
)
659+
.err();
673660

674661
if ψ_invalid.is_some() || ψˆ_invalid.is_some() || ψ_prime_invalid.is_some() {
675662
faulty_parties.push((
@@ -685,13 +672,9 @@ where
685672
return Err(SigningAborted::InvalidΨ(faulty_parties).into());
686673
}
687674

688-
// Step 2
675+
// Step 3
689676
self.tracer.stage("Compute Γ, Delta_i, delta_i, chi_i");
690-
let Γ = Γ_i
691-
+ round2_msgs
692-
.iter_indexed()
693-
.map(|(_, _, msg)| msg.Γ)
694-
.sum::<Point<E>>();
677+
let Γ = Γ_i + round2_msgs.iter().map(|msg| msg.Γ).sum::<Point<E>>();
695678
let Delta_i = Γ * &k_i;
696679

697680
let α_sum =

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