code: @Nullable
    public static String getWithoutPEMHeader (@Nullable final String sCertificate)
    {
      if (StringHelper.hasNoText (sCertificate))
        return null;
  
      // Remove special begin and end stuff
      String sRealCertificate = sCertificate.trim ();
  
      /**
       * Handle certain misconfiguration issues. E.g. for 9906:testconsip on
       *
       * <pre>
       * http://b-c073e04afb234f70e74d3444ba3f8eaa.iso6523-actorid-upis.acc.edelivery.tech.ec.europa.eu/iso6523-actorid-upis%3A%3A9906%3Atestconsip/services/busdox-docid-qns%3A%3Aurn%3Aoasis%3Anames%3Aspecification%3Aubl%3Aschema%3Axsd%3AOrder-2%3A%3AOrder%23%23urn%3Awww.cenbii.eu%3Atransaction%3Abiitrns001%3Aver2.0%3Aextended%3Aurn%3Awww.peppol.eu%3Abis%3Apeppol3a%3Aver2.0%3A%3A2.1
       * </pre>
       */
      sRealCertificate = StringHelper.trimStart (sRealCertificate, BEGIN_CERTIFICATE_INVALID);
      sRealCertificate = StringHelper.trimEnd (sRealCertificate, END_CERTIFICATE_INVALID);
  
      // Remove regular PEM headers also
      sRealCertificate = StringHelper.trimStart (sRealCertificate, BEGIN_CERTIFICATE);
      sRealCertificate = StringHelper.trimEnd (sRealCertificate, END_CERTIFICATE);
  
      // Remove all existing whitespace characters
      return StringHelper.getWithoutAnySpaces (sRealCertificate);
    }
docs: Remove any eventually preceding {@value #BEGIN_CERTIFICATE} and succeeding
  {@value #END_CERTIFICATE} values from the passed certificate string.
  Additionally all whitespaces of the string are removed.
  
  @param sCertificate
  The source certificate string. May be <code>null</code>.
  @return <code>null</code> if the input string is <code>null</code> or
  empty, the stripped down string otherwise.