Our Type 1 connectors have a small hole in the button that you can secure with a luggage sized padlock. We would rate this as medium security and better than the lock provided by in-car mechanisms such as those found on the nissan leaf. The most secure method is to use a 5cm padlock to secure directly onto the car or onto the charging point.
Type 2 cables can be locked electronically at the car and at the charge point but to totally secure your charger, you can use a 5cm lock in a number of ways depending on your charge point. Here are some examples: