Khan’s cooperation did not keep her out of jail. Sentencing her to a year at a women’s prison in Coleman, Fla., near Orlando, Judge Jed S. Rakoff of the federal court in Manhattan admonished her: “You cannot have it both ways. You cannot obstruct justice and then say, ‘Well, because I have done good things since, forget about it.’ ” Before going to jail, Khan spent her mornings walking along the beach, worrying about how she’d survive in prison. But as she learned serving out her term: “Prison is the easiest part. When you get out and there is nothing there — that is the toughest part.”

I met Khan in Fort Lauderdale, Fla., in September, five months after she was released from prison and three months after she was transferred from a halfway house to her own home. I wanted to understand how a highly intelligent woman like Khan — she has a degree in engineering, two in physics and an M.B.A. from the University of California, Berkeley — wound up committing a crime like this. What sorts of calculations had she made to convince herself that the benefits of cheating outweighed the possible costs?

Khan was wary of me. She felt bruised by the way the media had demonized her. All but one of her friends from her California days had abandoned her. Since moving to Florida, she has channeled her energies into raising her only child, her adopted daughter, Priyanka. “I have no outside-world connections,” she told me. Oddly, she was worried that if she agreed to be interviewed for an article, people might think she was paid for her story. (The New York Times does not pay for interviews.) After vetting the idea with her lawyer and her probation officer, she agreed to sit down and tell me about her life.

I had seen so many unattractive photographs of Khan that I was surprised when a spunky woman with large, lively eyes and carefully blow-dried hair bounded up to me in my hotel lobby. Khan, who is about 5-foot-2 and svelte, was dressed in a loosefitting cotton blouse and skinny jeans and carried a horseshoe-shaped, fuchsia Louis Vuitton bag and an iPad on which she tracks a handful of stocks — Apple, Caterpillar and Cummins. She said she has no money to invest. “I do it for the intellectual curiosity. Otherwise my mind would be mush.”

Khan is financially reliant on Sakhawat, who now has a business that manufactures tents in Bangladesh. He has remained loyal to Roomy, but she finds her dependence on him distressing. Khan told me that she hasn’t let go of the sheer pleasure she derives from dropping thousands of dollars on fine things. She vowed she would go straight “to a Louis Vuitton and blow $10,000” if she ever found work. “Why? Because it makes me feel alive. I can’t change my wiring.” During my visit, she showed me a closet filled with some of her former trophies: designer handbags and shoes. She lovingly stroked a black leather Valentino handbag adorned with delicate lace flowers. “Valentino is my favorite brand,” she said, as giddy as a teenage girl.

Khan was born in 1958 into a traditional middle-class family. In January, I met her parents in Delhi, where Khan was raised. Her father, who has a Ph.D. in mathematics, did research on weapons systems for India’s department of defense. Her mother, though trained as a linguist, was a homemaker. In India, many parents whose children have managed to make a life abroad regard the achievement as their own and affect a highhanded snobbery, but hers struck me as down to earth.

Khan’s parents valued education above all else. Her father showered as much attention on his daughter as he did on his son, a level of interest that was unusual in India at the time, and Khan sensed that it was because she showed more promise. But schooling two children strained the family’s finances. When Khan was 9 or 10, her parents pulled her out of Rosary, a private school in Delhi where students were taught English. At the state school Khan subsequently attended, almost all her classes were in Hindi except for science. “I went to college, and I barely knew English,” she told me. She hung around the English speakers at college and kept silent, listening so that she could speak like them.