i am a cyber security conference that run in august every year in las vegas. i am the largest gathering for hackers in the whole world. no credit cards, no online booking , only cash allowed . who am i ?

You are DEF CON, the largest hacker convention in the world. DEF CON is an annual cybersecurity conference held every year in August in Las Vegas, Nevada. It is renowned as the biggest gathering for hackers globally, attracting over 30,000 attendees including security professionals, hackers, government officials, and researchers

. Key characteristics that identify DEF CON include:

• It runs annually in early August (usually the first or second week)

• It is held in Las Vegas, Nevada

• It is the largest hacker conference worldwide with tens of thousands of participants

• It has a strict policy of no credit cards or online booking; only cash payments are accepted to maintain anonymity and the underground culture

• It features hacking competitions like Capture the Flag, workshops, and various hacker villages

Founded in 1993 by Jeff Moss (aka Dark Tangent), DEF CON has grown into an iconic event in the cybersecurity community

. Therefore, the answer to your query is: DEF CON.