“I get those letters every week,” Mr. Kurland said, referring to the mail he receives intended for his clients. “They range from congratulatory letters to individuals having a tough time asking for handouts, to organizations looking for donations, to business men and women asking for investors.”

Mr. Kurland, who calls himself the Lottery Lawyer and represented the person in South Carolina who won the $1.54 billion Mega Millions jackpot last year, advises his clients to delete all their social media accounts before they claim their winnings. He also tells them to try to remove their address from public view as much as they can and to get new phone numbers. If there are children involved, he will hire security for the first couple of days.

Mr. Kurland tries to help his clients retain some privacy after they win, but if privacy is hard to achieve in 2019, anonymity is nearly impossible.

“It is very hard to participate in civil life and be anonymous,” Albert Gidari, the privacy director of the Center for Internet and Society at Stanford Law School, said on Wednesday. “You can’t buy a car in cash and avoid disclosing who you are because now car dealers are financial institutions,” Mr. Gidari said, adding that it was nearly impossible to transfer money in and out of the United States without disclosing who you are to the government.

“He can get a lot of lawyers and accountants and figure out how to move and hide a lot of that money at great risk to himself for not complying with government reporting,” Mr. Gidari said. “You can’t get very far, but you can get far enough to get some degree of obscurity, even if you can’t get anonymity.”

Last year the winner of a $560 million Powerball jackpot in New Hampshire took the state to court to retain her anonymity while claiming her prize. The woman’s lawyers argued that she would be accosted with requests for money, and the state argued that lottery winners must be disclosed to make sure that winners are not related to lottery employees and that winnings are distributed fairly. The court decided disclosing the winner’s name would be an invasion of privacy and allowed the woman to anonymously claim her winnings.