title: How secure are Amazon AWS Access keys?
body: <p>I want to offer presigned urls to my s3 buckets with an expiry date.
  The .net sdk nicely generates these urls, but looking at them makes me worry a little:</p>
  
  <pre><code>https://s3.amazonaws.com/upload_youtipit/myfile?AWSAccessKeyId=**MYACCESSKEY**&amp;Expires=1317924047&amp;response-content-disposition=attachment;filename=feedback.jpg&amp;response-content-type=image/jpeg&amp;Signature=podKJSrNeFel6%2B0aOneb342H5GA%3D
  </code></pre>
  
  <p>Why does it need to put my (public) AWSAccessKey in the Url? Shouldn't this be kept a bit more confidential? I know its not the secret, but I still don't feel comfortable exposing it in public..</p>
  
  <p>How likely is it that, somebody who has my public key, can guess/bruteforce my private key? </p>