diff --git a/src/pages/create/index.tsx b/src/pages/create/index.tsx
index d14efd4..03ee993 100644
--- a/src/pages/create/index.tsx
+++ b/src/pages/create/index.tsx
@@ -410,7 +410,7 @@ export const CreatePage = () => {
       type: 'application/sigit'
     })
 
-    const fileUrl = await uploadToFileStorage(file, nostrController)
+    const fileUrl = await uploadToFileStorage(file)
       .then((url) => {
         toast.success('files.zip uploaded to file storage')
         return url
diff --git a/src/utils/misc.ts b/src/utils/misc.ts
index 7e59df4..148f75b 100644
--- a/src/utils/misc.ts
+++ b/src/utils/misc.ts
@@ -2,6 +2,7 @@ import axios from 'axios'
 import {
   Event,
   EventTemplate,
+  finalizeEvent,
   generateSecretKey,
   getPublicKey,
   nip04,
@@ -14,6 +15,7 @@ import store from '../store/store'
 import { CreateSignatureEventContent, Meta } from '../types'
 import { hexToNpub, now } from './nostr'
 import { parseJson } from './string'
+import { hexToBytes } from '@noble/hashes/utils'
 
 /**
  * Uploads a file to a file storage service.
@@ -21,10 +23,7 @@ import { parseJson } from './string'
  * @param nostrController The NostrController instance for handling authentication.
  * @returns The URL of the uploaded file.
  */
-export const uploadToFileStorage = async (
-  file: File,
-  nostrController: NostrController
-) => {
+export const uploadToFileStorage = async (file: File) => {
   // Define event metadata for authorization
   const event: EventTemplate = {
     kind: 24242,
@@ -38,8 +37,15 @@ export const uploadToFileStorage = async (
     ]
   }
 
-  // Sign the authorization event using the NostrController
-  const authEvent = await nostrController.signEvent(event)
+  const key = store.getState().userAppData?.keyPair?.private
+  if (!key) {
+    throw new Error(
+      'Key to interact with blossom server is not defined in user app data'
+    )
+  }
+
+  // Sign the authorization event using the dedicated key stored in user app data
+  const authEvent = finalizeEvent(event, hexToBytes(key))
 
   // URL of the file storage service
   const FILE_STORAGE_URL = 'https://blossom.sigit.io' // REFACTOR: should be an env