Function gen_session

controllers/sign.js:333–336

(user, res)

// private
function gen_session(user, res) {
  var auth_token = encrypt(user._id + '\t' + user.name + '\t' + user.pass + '\t' + user.email, config.session_secret);
  res.cookie(config.auth_cookie_name, auth_token, {path: '/', maxAge: 1000 * 60 * 60 * 24 * 30}); //cookie 有效期30天
}

function encrypt(str, secret) {
  var cipher = crypto.createCipher('aes192', secret);