Keto also can be known as Low Carb High Fat diet. Both dirty and clean keto are based on that.
Dirty keto is where you fill up mainly on meat, cheese and high fat options like butter, cream etc. Very similar to Atkins. Yes, you will lose weight but the nutrients you consume will not be as rounded as they could be.
Clean keto is the introduction of more of a paleo diet. So it's the inclusion of fats, but healthy fats. So more nuts, seeds, avocado's, oils etc....
With both you are encouraged to keep carb intake to 20-30g a day. However, how you choose to ingest those, from the approved list, determines the type of keto you follow.