… The case before the First Circuit was brought by investor James Harper, whose financial records the IRS obtained through a judicially enforced “John Doe summons” asking Coinbase to turn over information on thousands of account holders. John Doe summons, which don’t require a showing of probable cause, direct a third party to surrender information about taxpayers whose identities are unknown to the IRS…

“In one fell swoop, IRS effectively collected all cryptocurrency transactions linked to Coinbase transactions, past and future, for Harper and over 14,000 others,” states the brief written by his attorneys with the New Civil Liberties Alliance…