As long as you keep cryptocurrencies as an investment and don't generate any income, you generally don't have to pay taxes on cryptocurrencies until you sell them. You have to pay taxes on cryptocurrencies. The IRS classifies cryptocurrencies as property, and cryptocurrency transactions are subject to tax by law just like transactions related to any other property. Cryptocurrencies are considered property for federal income tax purposes.
And, for the typical investor, the IRS treats it as an equity asset. As a result, cryptocurrency taxes are no different from the taxes you pay on any other profit made from the sale or exchange of an equity asset. You owe taxes when you get or dispose of cryptocurrency. There is no way to legally evade taxes when converting cryptocurrencies into fiat currency.
This is considered an alienation event subject to capital gains tax. If you got rid of your cryptocurrency and then reinvested your funds, you'll still have to pay capital gains tax for your alienations. Trading one cryptocurrency for another is subject to capital gains tax. You'll incur a capital gain or loss depending on how the price of the cryptocurrency you're trading has changed since you originally received it.
You'll have to pay ordinary income taxes if you receive cryptocurrency in exchange for goods and services. In this case, your taxable situation is the same as if you had exchanged two other forms of ownership.