I ran across this video a while ago on what can happen to you if you don't pay your taxes. At some point during your Bitcoin career, the cryptocoin will be converted to fiat and that's how they will catch you.
https://www.youtube.com/watch?v=hf2fNEUPjQwThis is easy pay your taxes, I know that no one likes to do it, every time the government raises taxes no one is happy about it but if you like your freedom you need to do it especially since in my country jails are really not places where you want to be, so forget about trying to beat the system if at some point you're going to cash out then declare your profits and pay your taxes.
Exactly if you really don't like to pay tax to your government then don't convert your coins to fiat. use your coins directly to buy your needs that are the only option you left or else find a local buyer and sell your coins for direct cash. If you convert your coins into fiat using any exchange you must pay tax you don't any option.