diff --git a/functions/api/uploads/[[id]].ts b/functions/api/uploads/[[id]].ts
index 4745958..c909418 100644
--- a/functions/api/uploads/[[id]].ts
+++ b/functions/api/uploads/[[id]].ts
@@ -5,7 +5,7 @@ export async function onRequestGet(context: RequestContext) {
   ).toString()}`;
   const signingKey = await crypto.subtle.importKey(
     "raw",
-    new TextEncoder().encode(atob(context.env.URL_SIGNING_KEY)),
+    Uint8Array.from(atob(context.env.URL_SIGNING_KEY), (c) => c.charCodeAt(0)),
     { hash: "SHA-1", name: "HMAC" },
     false,
     ["sign"],
@@ -17,7 +17,10 @@ export async function onRequestGet(context: RequestContext) {
   );
 
   return Response.redirect(
-    `${unsignedURL}&Signature=${btoa(new TextDecoder().decode(signature))
+    `${unsignedURL}&Signature=${btoa(
+      // @ts-expect-error
+      String.fromCodePoint(...signature),
+    )
       .replaceAll("+", "-")
       .replaceAll("/", "_")
       .replaceAll("=", "")}`,