From 77f1562a30807cfc3b74f03e19c5cbe5d7c0fe90 Mon Sep 17 00:00:00 2001
From: Paul Miller <paul@paulmillr.com>
Date: Tue, 26 Nov 2024 13:49:08 +0000
Subject: [PATCH] webcrypto: improve managedNonce

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

diff --git a/src/webcrypto.ts b/src/webcrypto.ts
index a247c0c..4ae0d34 100644
--- a/src/webcrypto.ts
+++ b/src/webcrypto.ts
@@ -44,10 +44,10 @@ type CipherWithNonce = ((key: Uint8Array, nonce: Uint8Array, ...args: any[]) =>
 
 // Uses CSPRG for nonce, nonce injected in ciphertext
 export function managedNonce<T extends CipherWithNonce>(fn: T): RemoveNonce<T> {
-  anumber(fn.nonceLength);
+  const { nonceLength } = fn;
+  anumber(nonceLength);
   return ((key: Uint8Array, ...args: any[]): any => ({
     encrypt(plaintext: Uint8Array, ...argsEnc: any[]) {
-      const { nonceLength } = fn;
       const nonce = randomBytes(nonceLength);
       const ciphertext = (fn(key, nonce, ...args).encrypt as any)(plaintext, ...argsEnc);
       const out = concatBytes(nonce, ciphertext);
@@ -55,7 +55,6 @@ export function managedNonce<T extends CipherWithNonce>(fn: T): RemoveNonce<T> {
       return out;
     },
     decrypt(ciphertext: Uint8Array, ...argsDec: any[]) {
-      const { nonceLength } = fn;
       const nonce = ciphertext.subarray(0, nonceLength);
       const data = ciphertext.subarray(nonceLength);
       return (fn(key, nonce, ...args).decrypt as any)(data, ...argsDec);