From a9b6007768d5806c35bca3d5c8c5956f6c0fdc67 Mon Sep 17 00:00:00 2001
From: Chris Duncan <chris@zoso.dev>
Date: Sat, 15 Aug 2026 22:48:43 -0700
Subject: [PATCH] Fix constant time zero check that was incorrect due to
 AssemblyScript shift operand masking.

---
 src/assembly/utils.ts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/assembly/utils.ts b/src/assembly/utils.ts
index dee20aa..13c5357 100644
--- a/src/assembly/utils.ts
+++ b/src/assembly/utils.ts
@@ -37,9 +37,10 @@ export function negative (b: i8): u8 {
 //@ts-expect-error
 @inline
 export function sodium_is_zero (n: StaticArray<u8>, nlen: i32): u8 {
-	let d: u8 = 0
+	let d: i32 = 0
 	for (let i: i32 = 0; i < nlen; i++) {
 		d |= n[i]
 	}
-	return 1 & ((d - 1) >> 8)
+	d &= 255
+	return u8(((d - 1) >> 8) & 1)
 }
-- 
2.52.0