From 22bcfd2c340a8cb682468e5a7112404aee1e3849 Mon Sep 17 00:00:00 2001
From: Nishant Das <nishdas93@gmail.com>
Date: Tue, 22 Sep 2020 23:23:33 +0800
Subject: [PATCH] Update Message ID (#7304)

* shorten message id
* Merge refs/heads/master into updateMessageID
* Merge refs/heads/master into updateMessageID
---
 beacon-chain/p2p/pubsub.go      | 7 ++-----
 beacon-chain/p2p/pubsub_test.go | 3 +--
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/beacon-chain/p2p/pubsub.go b/beacon-chain/p2p/pubsub.go
index 75f6795a9..736177583 100644
--- a/beacon-chain/p2p/pubsub.go
+++ b/beacon-chain/p2p/pubsub.go
@@ -2,7 +2,6 @@ package p2p
 
 import (
 	"context"
-	"encoding/base64"
 	"time"
 
 	pubsub "github.com/libp2p/go-libp2p-pubsub"
@@ -80,12 +79,10 @@ func (s *Service) SubscribeToTopic(topic string, opts ...pubsub.SubOpt) (*pubsub
 // Content addressable ID function.
 //
 // ETH2 spec defines the message ID as:
-//    message-id: base64(SHA256(message.data))
-// where base64 is the URL-safe base64 alphabet with
-// padding characters omitted.
+//    message-id: SHA256(message.data)[:8]
 func msgIDFunction(pmsg *pubsub_pb.Message) string {
 	h := hashutil.Hash(pmsg.Data)
-	return base64.RawURLEncoding.EncodeToString(h[:])
+	return string(h[:8])
 }
 
 func setPubSubParameters() {
diff --git a/beacon-chain/p2p/pubsub_test.go b/beacon-chain/p2p/pubsub_test.go
index fb76de182..8c9b95dc1 100644
--- a/beacon-chain/p2p/pubsub_test.go
+++ b/beacon-chain/p2p/pubsub_test.go
@@ -2,7 +2,6 @@ package p2p
 
 import (
 	"context"
-	"encoding/base64"
 	"fmt"
 	"sync"
 	"testing"
@@ -34,6 +33,6 @@ func TestMessageIDFunction_HashesCorrectly(t *testing.T) {
 	msg := [32]byte{'J', 'U', 'N', 'K'}
 	pMsg := &pubsubpb.Message{Data: msg[:]}
 	hashedData := hashutil.Hash(pMsg.Data)
-	msgID := base64.RawURLEncoding.EncodeToString(hashedData[:])
+	msgID := string(hashedData[:8])
 	assert.Equal(t, msgID, msgIDFunction(pMsg), "Got incorrect msg id")
 }