How to protect points in an online game from cheating?

Question

Game development

We launched a competition in the form of an online game created on c2. Periodically, we observe an attempt to hack the game and cheat points in the ranking. We pre-installed encrypted data, connected an SSL certificate. There were craftsmen who started downloading the game to local machines and trying to crack the rating.
Tell me, what tools and approaches can be used to protect the rating and identify violators?

Answer 1

1. Forced authorization through the social network.
2. Do not miss fresh social media accounts.
3. At the time of voting, write down the ID in the database and do not let you vote anymore.
4. Captcha.

Answer 2

voice confirmation via SMS or, at worst, a social network