From 25a3450f37b909e48f30a33146be990f35e3250c Mon Sep 17 00:00:00 2001
From: programmer10110 <programmer10110@yandex.ru>
Date: Sun, 26 Jul 2020 20:46:39 +0300
Subject: [PATCH] fix calculating participantID

---
 dkg/dkg.go | 31 +++++++++++++++++++++++++------
 main.go    | 16 +++++++++++++++-
 2 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/dkg/dkg.go b/dkg/dkg.go
index 7684935..588f0e0 100644
--- a/dkg/dkg.go
+++ b/dkg/dkg.go
@@ -3,6 +3,7 @@ package dkg
 import (
 	"errors"
 	"fmt"
+	"math"
 	"sort"
 	"sync"
 
@@ -37,7 +38,6 @@ func Init() *DKG {
 
 	d.deals = make(map[string]*dkg.Deal)
 	d.commits = make(map[string][]kyber.Point)
-	d.responses = newMessageStore(9)
 
 	return &d
 }
@@ -56,10 +56,33 @@ func (d *DKG) StorePubKey(participant string, pk kyber.Point) bool {
 	})
 }
 
+func (d *DKG) calcParticipantID() int {
+	for idx, p := range d.pubkeys {
+		if p.PK.Equal(d.pubKey) {
+			return idx
+		}
+	}
+	return -1
+}
+
 func (d *DKG) InitDKGInstance(t int) (err error) {
 	sort.Sort(d.pubkeys)
 
-	d.instance, err = dkg.NewDistKeyGenerator(d.suite, d.secKey, d.pubkeys.GetPKs(), t)
+	publicKeys := d.pubkeys.GetPKs()
+
+	participantsCount := len(publicKeys)
+
+	participantID := d.calcParticipantID()
+
+	if participantID < 0 {
+		return fmt.Errorf("failed to determine participant index")
+	}
+
+	d.ParticipantID = participantID
+
+	d.responses = newMessageStore(int(math.Pow(float64(participantsCount)-1, 2)))
+
+	d.instance, err = dkg.NewDistKeyGenerator(d.suite, d.secKey, publicKeys, t)
 	if err != nil {
 		return err
 	}
@@ -82,10 +105,6 @@ func (d *DKG) GetDeals() (map[int]*dkg.Deal, error) {
 	if err != nil {
 		return nil, err
 	}
-	for _, deal := range deals {
-		d.ParticipantID = int(deal.Index) // Same for each deal.
-		break
-	}
 	return deals, nil
 }
 
diff --git a/main.go b/main.go
index ac4b9be..a775989 100644
--- a/main.go
+++ b/main.go
@@ -23,6 +23,15 @@ type Transport struct {
 	nodes []*dkglib.DKG
 }
 
+func (t *Transport) getNodeByParticipantID(id int) *dkglib.DKG {
+	for _, node := range t.nodes {
+		if node.ParticipantID == id {
+			return node
+		}
+	}
+	return nil
+}
+
 func (t *Transport) BroadcastPK(participant string, pk kyber.Point) {
 	for idx, node := range t.nodes {
 		if ok := node.StorePubKey(participant, pk); !ok {
@@ -39,7 +48,12 @@ func (t *Transport) BroadcastCommits(participant string, commits []kyber.Point)
 
 func (t *Transport) BroadcastDeals(participant string, deals map[int]*dkg.Deal) {
 	for index, deal := range deals {
-		t.nodes[index].StoreDeal(participant, deal)
+		dstNode := t.getNodeByParticipantID(index)
+		if dstNode == nil {
+			fmt.Printf("Node with index #%d not found\n", index)
+			continue
+		}
+		dstNode.StoreDeal(participant, deal)
 	}
 }