Diddy -- Someone Jacked My Credit Card Info

Diddy is on a mission to find the person who stole the numbers to his personal American Express Black Card and posted them on a web site this week ... TMZ has learned.

Earlier this week, someone who clearly has a beef with Diddy, posted copies of the rap mogul's super exclusive credit card on a website, along with his passport and private phone numbers.

The website where the info is posted seems to make a vague reference to the ridiculous rumors that Diddy is a member of the Illuminati ... a secret society rumored to run the world.

Sources close to Diddy tell us ... he is aware of the situation and has launched an internal investigation to find the person responsible.