In my opinion you're dealing with a form of public funds since lotteries are voluntary taxation, therefore the winner has to be disclosed in some manner to inform people that it was not a rigged draw.
Found this on the Powerball site where laws in LA permitted some anonymity. I'd personally find a good tax attorney, which would be needed anyway, and let them do the talking.
"Duchess Trust
February 12, 2005
Louisiana
BATON ROUGE, La. – Just before noon this morning at the Louisiana Lottery's headquarters in Baton Rouge, local attorney Stephanie LaBorde claimed the $40.6 million Feb. 12 Powerball jackpot prize on behalf of her client, who established The Duchess Trust to receive the winnings.
The winner chose the one-time cash payment option of $23,041,529.64, which amounted to $16,129,070.75 after state and federal taxes were withheld.
According to LaBorde, her client is a 55-year-old, long-time Baton Rouge resident who owns her own governmental relations practice. She also said the winner was a regular Lottery player who purchased $5 dollars worth of Powerball tickets every Saturday.
LaBorde said her client plans to pay off debt, help friends, family and charitable causes, and slow down a bit. "She's also revised the budget for purchasing a replacement house since hers is currently up for sale," said LaBorde.
About one week before hitting the Powerball jackpot, LaBorde said the winner adopted an abandoned Labrador retriever and called him her "lucky dog," since the dog was destined for a better life. "She's convinced the dog was her good luck talisman," said LaBorde of the winner.
The winning ticket was purchased at 6:42 p.m. on Feb. 12 at the Shell Food Mart on College Drive. The ticket was a quick pick, meaning the Lottery's terminal randomly selected the numbers. The retailer will receive a $25,000 bonus for selling the winning ticket. The winning numbers for the Feb. 12 drawing were 18-21-28-49-50 and the Powerball was 16.
There have been eight previous Louisiana Powerball jackpot winners. The Feb. 12 jackpot was the second largest single-ticket jackpot winner sold in Louisiana and the first ever sold in Baton Rouge. The last time a Powerball jackpot was won in Louisiana was Feb. 22, 2003, claimed by Cello Investments LLC of Belle Chase.
The Lottery encourages anyone who thinks they may have a gambling problem or has friends or family who may have a gambling problem to call toll free 1-877-770-7867. Ticket purchasers must be at least 21 years of age."
http://www.powerball.com/powerball/winners/2005/021205la.shtm