Just as Flatless commented earlier, crypto taxation varies in different countries. Taking my country for example, the crypto tax is newly implemented, it is just few months old actually and it is 10% of capital gains. The procedures and guidelines to enforce the tax is being worked upon by the Federal Inland Revenue (FIR) and Joint Task Board but my guess is, it will be through centralized exchanges that have the jurisdiction to operate in my country. The tax implementation is still not glaring at the moment but I think P2P users will be able to get off the hook.