From 8c34c4cbb3780c433148966a004f5a51aace0f64 Mon Sep 17 00:00:00 2001
From: Mathias Hall-Andersen <mathias@hall-andersen.dk>
Date: Fri, 4 Aug 2017 16:15:53 +0200
Subject: First set of code review patches

---
 src/noise_types.go | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

(limited to 'src/noise_types.go')

diff --git a/src/noise_types.go b/src/noise_types.go
index 5ebc130..1a944df 100644
--- a/src/noise_types.go
+++ b/src/noise_types.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"crypto/subtle"
 	"encoding/hex"
 	"errors"
 	"golang.org/x/crypto/chacha20poly1305"
@@ -31,12 +32,12 @@ func loadExactHex(dst []byte, src string) error {
 }
 
 func (key NoisePrivateKey) IsZero() bool {
-	for _, b := range key[:] {
-		if b != 0 {
-			return false
-		}
-	}
-	return true
+	var zero NoisePrivateKey
+	return key.Equals(zero)
+}
+
+func (key NoisePrivateKey) Equals(tar NoisePrivateKey) bool {
+	return subtle.ConstantTimeCompare(key[:], tar[:]) == 1
 }
 
 func (key *NoisePrivateKey) FromHex(src string) error {
@@ -55,6 +56,15 @@ func (key NoisePublicKey) ToHex() string {
 	return hex.EncodeToString(key[:])
 }
 
+func (key NoisePublicKey) IsZero() bool {
+	var zero NoisePublicKey
+	return key.Equals(zero)
+}
+
+func (key NoisePublicKey) Equals(tar NoisePublicKey) bool {
+	return subtle.ConstantTimeCompare(key[:], tar[:]) == 1
+}
+
 func (key *NoiseSymmetricKey) FromHex(src string) error {
 	return loadExactHex(key[:], src)
 }
-- 
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