If you sign in to WordPress.com via a non-secure Internet connection, like a public Wi-Fi connection at your local coffee shop, your account may be more vulnerable to hijacking. To keep the bad guys out, we recommend selecting the “Always use HTTPS when visiting administration pages“ option from your Personal Settings page (Dashboard > Users menu > Personal Settings) which will SSL-encrypt your connection while in the WordPress.com dashboard. Save the change by clicking Save Changes. When you log back in, you’ll be rolling with SSL encryption.
Why use HTTPS in wordpress?