From 3f436d2a86297a4c9d892c505cc490cdd6c76361 Mon Sep 17 00:00:00 2001
From: fiatjaf <fiatjaf@gmail.com>
Date: Mon, 12 May 2025 05:59:21 -0300
Subject: [PATCH] nip13: fix leading zeroes check (remainings from hex era).

---
 nip13/nip13.go | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/nip13/nip13.go b/nip13/nip13.go
index f5b2bcb..e557882 100644
--- a/nip13/nip13.go
+++ b/nip13/nip13.go
@@ -3,7 +3,6 @@ package nip13
 import (
 	"context"
 	"crypto/sha256"
-	"encoding/hex"
 	"errors"
 	"math/bits"
 	"runtime"
@@ -39,16 +38,12 @@ func CommittedDifficulty(event nostr.Event) int {
 // Difficulty counts the number of leading zero bits in an event ID.
 func Difficulty(id nostr.ID) int {
 	var zeros int
-	var b [1]byte
-	for i := 0; i < 32; i += 2 {
+	for i := 0; i < 32; i++ {
 		if id[i] == 0 {
 			zeros += 8
 			continue
 		}
-		if _, err := hex.Decode(b[:], []byte{id[i], id[i+1]}); err != nil {
-			return -1
-		}
-		zeros += bits.LeadingZeros8(b[0])
+		zeros += bits.LeadingZeros8(id[i])
 		break
 	}
 	return zeros