Pakistan has seen a boom in trading and mining cryptocurrency, with interest proliferating in thousands of views of related videos on social media and transactions on online exchanges
Bitcoin tumbled 11% on Monday, its largest one-day drop in over a month, with losses of nearly 30% in the last week alone almost wiping out gains for the year-to-date.
McAfee linked the charges filed by the Internal Revenue Service to his failed bid to run as a Libertarian Party candidate in the 2020 US presidential election, a second such attempt.
"I am hoping that the Spanish court will see the injustice of this," he said, adding "the United States wants to use me as an example."
While standards are widely seen to have improved, global regulators and policymakers have in recent months voiced concerns over the illicit use of crypto.
Larger rival Bitcoin also gained in its wake with the world's biggest and best-known cryptocurrency rising 3.7% to $36,977 in quiet trading with London and US markets shut for holidays.
Bitcoin has been less volatile in recent days but is down by more than 35% this month, weighed by growing regulatory pressures on the sector.