await promises in place

src/pwd-box.ts

@@ -13,7 +13,7 @@ export default class PwdBox {
 
   private static async derive(pwd: string, salt: Uint8Array): Promise<CryptoKey> {
     const k = await pbkdf(salt, pwd)
-    return (await hkdf(k, Usage.box)) as CryptoKey
+    return await hkdf(k, Usage.box) as CryptoKey
   }
 
   public static async encrypt(data: Uint8Array, pwd: string): Promise<PwdBox> {
@@ -26,7 +26,7 @@ export default class PwdBox {
   public async decrypt(pwd: string): Promise<Uint8Array | null> {
     log.trace('decrypt')
     const k = await PwdBox.derive(pwd, this.salt)
-    return this.box.decrypt(k)
+    return await this.box.decrypt(k)
   }
 
   public toString(): string {