This is exactly what the military coup did in Margaret Atwood's book "The Handmaid's Tale." They created a digital currency where all transactions were via a debit card, then would lock down the accounts of certain segments (in this case, women). The book came out in the 80s, before debit cards. I remember at first refusing to use my debit card for a long time.
Of course, in Atwood's novel, the villain was a hardcore conservative Christian. As they say in Libville, "Because reasons."