title: Generating Paypal Signature, 'X-PAYPAL-AUTHORIZATION' in Ruby
body: <p>Is there any library in Ruby that generates the Signature, <code>'X-PAYPAL-AUTHORIZATION'</code> header that is required to make calls on behalf of the account holder who has authorized us through the paypal Permissions API.
  I am done with the permissions flow and get the required access token, tokenSecret. I feel I am generating the signature incorrectly as all my calls with the the generated 'X-PAYPAL-AUTHORIZATION' fail. They give the following errors:<br/><br />
  <strong>For NVP call I get:</strong><br/>
  <code>You do not have permissions to make this API call</code><br /></p>
  
  <p><strong>And for the GetBasicPersonalData call I get:</strong><br />
  <code>Authentication failed. API credentials are incorrect.</code><br /></p>
  
  <p>Has anyone gone through this in Ruby? What is best way to generate signature. Paypal has just provided some SDK in Paypal, Java, but not the algorithm to generate signature.</p>
  
  <p>Thanks,<br />
  Nilesh</p>