I don't know about the US, but this is a copy and paste of section 1 of the Theft Act 1968
Basic definition of theft.
(1)A person is guilty of theft if he dishonestly appropriates property belonging to another with the intention of permanently depriving the other of it; and “thief” and “steal” shall be construed accordingly.
(2)It is immaterial whether the appropriation is made with a view to gain, or is made for the thief’s own benefit.
Therefore dishonestly appropriating crypo coins is stealing and the person doing it is a thief by British legal definitions so they could be done as a common thief.
Since basically the entire US legal system (including large chunks of their constitution and bill of rights) are largely a copy and paste of the British legal system as it stood in the law books they had in 1776 it would be surprising if their acts regarding theft are massively divergent from that.