why base64EncodeData does't work?
<pre><code>NSString *result  = [encData base64EncodeData:encData];  
</code></pre>

<p>why base64EncodeData does't work??
 it had the message like:</p>

<blockquote>
  <p>-[NSConcreteData base64EncodeData:]: unrecognized selector sent to instance 0x4e1f020</p>
</blockquote>

<p>Any suggestion??</p>
