title: Where is the PEM file format specified?
body: <p>I need to parse .PEM files.<br>
  I know that the standard for "Privacy-enhanced Electronic Mail" is defined in RFCs 1421-24. But they don't seem to mention some text I find inside OpenSSL .pem files (eg. "Key Attributes", "BEGIN CERTIFICATE", etc...) 
  Is this an OpenSSL-specific format?</p>