Neither because buying bitcoins doesn't help you not pay taxes.

If you have legitimate money that's reported to the IRS and taxed, what you do with it is largely irrelevant.

If you have illegitimate money (selling drugs, working under the table, etc) then you're not paying taxes on it to begin with. Buying bitcoin doesn't change that.

(And if you're paid in bitcoin, that's bartering and you either report it or you evade it.)