title: Standard format for digital signature
body: <p>I want to make a javascript library for signing messages. I expect the format to be something like...</p>
  
  <pre><code>--- BEGIN SIGNED MESSAGE ---
  This is a plain old message
  It goes on and on...
  --- BEGIN RSA OF SHA1 ---
  Base64Stringassfd86asdf870n8
  09as8d76fn098==
  --- END SIGNED MESSAGE ---
  </code></pre>
  
  <p>But I don't know the correct format. I could replicate PGP format (I am sure it is not hard to find info on that) but I would prefer to use a standard method if there is one.</p>
  
  <p>Is there a standard format for this kind of signed message?</p>