From: Chris Duncan <chris@zoso.dev>
Date: Sun, 16 Aug 2026 05:48:43 +0000 (-0700)
Subject: Fix constant time zero check that was incorrect due to AssemblyScript shift operand... 
X-Git-Url: https://git.codecow.com/?a=commitdiff_plain;h=a9b6007768d5806c35bca3d5c8c5956f6c0fdc67;p=nano25519.git

Fix constant time zero check that was incorrect due to AssemblyScript shift operand masking.
---

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)
 }