Encrypt the password string in web.config
<system.net>
    <mailSettings>
      <smtp deliveryMethod="Network">
        <network host="smtp.gmail.com" userName="guess@gmail.com" password="test" port="587" />
      </smtp>
    </mailSettings>
</system.net>

<configSections>
   <section
      name="sampleSection"
      type="System.Configuration.SingleTagSectionHandler"
   />
</configSections>

<MySecrets
   FavoriteMusic="Disco"
   FavoriteLanguage="COBOL"
   DreamJob="Dancing in the opening ceremonies of the Olympics"
/>

aspnet_regiis -pef MySecrets