Once you activate email verification, the system will message your verified email whenever a change has been made to your account. This way, you'll be notified immediately about any suspicious activity on you account.
To say thanks to players, Riot is also offering a 4-win Influence Points boost to everyone that establishes a verified email account.
To activate email verification simply head to leagueoflegends.com, sign in, click on your summoner name, and follow the prompts.
Riot says that this is just the first of many other security feature it's looking into to keep players' account details safe, indicating that SMS protection might be coming soon as well.