it's a trust-based system where you need to maintain proper accounting records.

record your buy quantity and fiat amount, along with any sell quantity and fiat amount, and be sure to keep track of any fees separately.  all timestamped.

most people use the first in, first out (FIFO) method when processing the data.

hire a professional tax adviser if you're worried about being flagged for audit.

Taranis

Thanks for your answer. The tax situation it's the least commented topic in the space. You can report the taxable event, but you will need to prove the purchase price, and if you can't, for my understanding it will be 0. So you will have to pay around a 20% of the full amount you sold? And not on the capital gain.

I'm not expert in this area, but I believe clarity is needed

bitcoin

Why so much hate to the Exchanges?

Hermit

Thanks for your answer. The tax situation it's the least commented topic in the space. You can report the taxable event, but you will need to prove the purchase price, and if you can't, for my understanding it will be 0. So you will have to pay around a 20% of the full amount you sold? And not on the capital gain. 

I'm not expert in this area, but I believe clarity is needed