Where can I buy an arb protocol?

Could you please enlighten me as to where I might acquire an arb protocol? I've been hearing a lot about its potential in the cryptocurrency sphere and I'm keen on exploring it further. Is there a specific exchange or platform that offers this protocol? Or perhaps, are there any reliable brokers or dealers who might have it in their inventory? I'm also curious about the regulations surrounding the purchase of such protocols, as I want to ensure that I'm operating within the legal framework. Thank you for your assistance in this matter.