function encryptMail(e) {
  try {
    // get the first message from the drafts folder in Gmail
    var draft = GmailApp.search('in:drafts')[0].getMessages()[0];

    // retrieve the email body in plain text
    // ( you can also do getBody() for HTML Mail )
    var body = draft.getPlainBody();
    var to = draft.getTo();
    var subject = draft.getSubject();

    // The encrypted message is in JSON format
    var json = sjcl.encrypt(e.parameter.password, body);
    // Convert the JSON to base64 (easier to copy-paste)
    var msg = Utilities.base64Encode(Utilities.jsonStringify(json));

    // Send the encrypted message via Gmail
    GmailApp.sendEmail(to, subject, msg);
  } catch (e) {
    Logger.log(e.toString());
  }
}