title: DropBox IOS SDk retrieving access token and secret is invalid once user is Authenticated
body: <p>Cross authentication of a dropbox user using Access token and secret not happening.</p>
  
  <p>Elaborating my Question: </p>
  
  <ol>
  <li>authenticate the user in my IOS app</li>
  <li>In Ios app , I retrieve access token and secret from MPOAuthCredentialConcreteStore *credentials.</li>
  <li><p>get the access token from credentials->acccessToken and similarly the secret.</p></li>
  <li><p>Now if I feed these values into another app  outside IOS which uses python sdk for dropbox. I get a error message "Invalid token".</p></li>
  </ol>
  
  <p>But, interestingly the reverse process from step 1 to 4 works. i.e get access token and secret from python SDK and feed it to my IOS app by using </p>
  
  <pre><code>[dbSession updateAccessToken:@"xxxxxxxxx" accessTokenSecret:@"YYYYYYYYYYY" forUserId:@"12345678"];
  </code></pre>
  
  <p>and now i can assess user's dropbox account. Any idea as to whats going wrong? Is there a difference between MPoauth and Oauth? I believe MPoauth is just a wrapper right?</p>
  
  <p>is there any other way to get the access token and secret? </p>
  
  <p>Thanks for the help.</p>