diff --git a/config/api.json b/config/api.json
index 4ff56b6..56eedcc 100644
--- a/config/api.json
+++ b/config/api.json
@@ -4,6 +4,6 @@
   "redirectUri": "http://localhost",
   "authApi": "https://login.microsoftonline.com/common/oauth2/v2.0/token",
   "driveApi": "https://graph.microsoft.com/v1.0/me/drive",
-  "scope": "Files.Read.All Files.ReadWrite.All offline_access",
+  "scope": "user.read files.read.all offline_access",
   "directLink": "https://public.dm.files.1drv.com"
 }
diff --git a/config/site.json b/config/site.json
index 19f5912..33b90f3 100644
--- a/config/site.json
+++ b/config/site.json
@@ -1,4 +1,5 @@
 {
+  "userPrincipalName": "spencer.woo@outlook.com",
   "icon": "/icons/128.png",
   "title": "Spencer's OneDrive",
   "baseDirectory": "/Public",
diff --git a/pages/_app.tsx b/pages/_app.tsx
index 6fa57a8..a707042 100644
--- a/pages/_app.tsx
+++ b/pages/_app.tsx
@@ -23,6 +23,7 @@ import {
   faCheckCircle,
 } from '@fortawesome/free-regular-svg-icons'
 import {
+  faCheck,
   faPlus,
   faMinus,
   faCopy as faCopySolid,
@@ -89,6 +90,7 @@ library.add(
   faExclamationCircle,
   faExclamationTriangle,
   faHome,
+  faCheck,
   faCheckCircle,
   ...iconList
 )
diff --git a/pages/onedrive-vercel-index-oauth/step-3.tsx b/pages/onedrive-vercel-index-oauth/step-3.tsx
index 8059849..e6857a4 100644
--- a/pages/onedrive-vercel-index-oauth/step-3.tsx
+++ b/pages/onedrive-vercel-index-oauth/step-3.tsx
@@ -1,4 +1,3 @@
-import axios from 'axios'
 import Head from 'next/head'
 import Image from 'next/image'
 import { useRouter } from 'next/router'
@@ -9,7 +8,7 @@ import siteConfig from '../../config/site.json'
 import Navbar from '../../components/Navbar'
 import Footer from '../../components/Footer'
 
-import { obfuscateToken, requestTokenWithAuthCode } from '../../utils/oAuthHandler'
+import { getAuthPersonInfo, requestTokenWithAuthCode, sendTokenToServer } from '../../utils/oAuthHandler'
 import { LoadingIcon } from '../../components/Loading'
 
 export default function OAuthStep3({ accessToken, expiryTime, refreshToken, error, description, errorUri }) {
@@ -27,48 +26,59 @@ export default function OAuthStep3({ accessToken, expiryTime, refreshToken, erro
   }, [expiryTimeLeft])
 
   const [buttonContent, setButtonContent] = useState(
-    <>
+    <div>
       <span>Store tokens</span> <FontAwesomeIcon icon="key" />
-    </>
+    </div>
   )
+  const [buttonError, setButtonError] = useState(false)
 
   const sendAuthTokensToServer = async () => {
+    setButtonError(false)
     setButtonContent(
-      <>
+      <div>
         <span>Storing tokens</span> <LoadingIcon className="animate-spin w-4 h-4 ml-1 inline" />
-      </>
+      </div>
     )
 
-    await axios
-      .post(
-        '/api',
-        {
-          obfuscatedAccessToken: obfuscateToken(accessToken),
-          accessTokenExpiry: parseInt(expiryTime),
-          obfuscatedRefreshToken: obfuscateToken(refreshToken),
-        },
-        {
-          headers: {
-            'Content-Type': 'application/json',
-          },
-        }
+    // verify identity of the authenticated user with the Microsoft Graph API
+    const { data, status } = await getAuthPersonInfo(accessToken)
+    if (status !== 200) {
+      setButtonError(true)
+      setButtonContent(
+        <div>
+          <span>Error validating identify, restart</span> <FontAwesomeIcon icon="exclamation-circle" />
+        </div>
       )
-      .then(_ => {
-        setButtonContent(
-          <>
-            <span>Stored! Going home...</span> <FontAwesomeIcon icon="check" />
-          </>
-        )
+      return
+    }
+    if (data.userPrincipalName !== siteConfig.userPrincipalName) {
+      setButtonError(true)
+      setButtonContent(
+        <div>
+          <span>Do not pretend to be the site owner</span> <FontAwesomeIcon icon="exclamation-circle" />
+        </div>
+      )
+      return
+    }
 
+    await sendTokenToServer(accessToken, refreshToken, expiryTime)
+      .then(() => {
+        setButtonError(false)
+        setButtonContent(
+          <div>
+            <span>Stored! Going home...</span> <FontAwesomeIcon icon="check" />
+          </div>
+        )
         setTimeout(() => {
           router.push('/')
         }, 2000)
       })
       .catch(_ => {
+        setButtonError(true)
         setButtonContent(
-          <>
+          <div>
             <span>Error storing the token</span> <FontAwesomeIcon icon="exclamation-circle" />
-          </>
+          </div>
         )
       })
   }
@@ -168,7 +178,11 @@ export default function OAuthStep3({ accessToken, expiryTime, refreshToken, erro
 
                 <div className="text-right mb-2 mt-6">
                   <button
-                    className="text-white bg-gradient-to-br from-green-500 to-teal-300 hover:bg-gradient-to-bl focus:ring-4 focus:ring-green-200 dark:focus:ring-green-800 font-medium rounded-lg text-sm px-4 py-2.5 text-center disabled:cursor-not-allowed disabled:grayscale"
+                    className={`text-white bg-gradient-to-br hover:bg-gradient-to-bl focus:ring-4 font-medium rounded-lg text-sm px-4 py-2.5 text-center ${
+                      buttonError
+                        ? 'from-red-500 to-orange-400 focus:ring-red-200 dark:focus:ring-red-800'
+                        : 'from-green-500 to-teal-300 focus:ring-green-200 dark:focus:ring-green-800'
+                    }`}
                     onClick={sendAuthTokensToServer}
                   >
                     {buttonContent}
diff --git a/utils/oAuthHandler.ts b/utils/oAuthHandler.ts
index 8b8202b..1f5203f 100644
--- a/utils/oAuthHandler.ts
+++ b/utils/oAuthHandler.ts
@@ -19,7 +19,7 @@ export function revealObfuscatedToken(obfuscated: string): string {
 
 // Generate the Microsoft OAuth 2.0 authorization URL, used for requesting the authorisation code
 export function generateAuthorisationUrl(): string {
-  const { clientId, redirectUri, authApi } = apiConfig
+  const { clientId, redirectUri, authApi, scope } = apiConfig
   const authUrl = authApi.replace('/token', '/authorize')
 
   // Construct URL parameters for OAuth2
@@ -27,7 +27,7 @@ export function generateAuthorisationUrl(): string {
   params.append('client_id', clientId)
   params.append('redirect_uri', redirectUri)
   params.append('response_type', 'code')
-  params.append('scope', 'files.readwrite offline_access')
+  params.append('scope', scope)
   params.append('response_mode', 'query')
 
   return `${authUrl}?${params.toString()}`
@@ -82,3 +82,30 @@ export async function requestTokenWithAuthCode(
       return { error, errorDescription: error_description, errorUri: error_uri }
     })
 }
+
+// Verify the identity of the user with the access token and compare it with the userPrincipalName
+// in the Microsoft Graph API. If the userPrincipalName matches, proceed with token storing.
+export async function getAuthPersonInfo(accessToken: string) {
+  const profileApi = apiConfig.driveApi.replace('/drive', '')
+  return axios.get(profileApi, {
+    headers: {
+      Authorization: `Bearer ${accessToken}`,
+    },
+  })
+}
+
+export async function sendTokenToServer(accessToken: string, refreshToken: string, expiryTime: string) {
+  return await axios.post(
+    '/api',
+    {
+      obfuscatedAccessToken: obfuscateToken(accessToken),
+      accessTokenExpiry: parseInt(expiryTime),
+      obfuscatedRefreshToken: obfuscateToken(refreshToken),
+    },
+    {
+      headers: {
+        'Content-Type': 'application/json',
+      },
+    }
+  )
+}