Feted in death as India's 'Braveheart', the 23-year-old whose gang rape rocked a nation is remembered by family and friends as a fearless and inspirational student with a fierce determination.

The story of a young woman whose father had moved from the countryside to the city and sold his ancestral land to help fund her studies, resonated with the dreams of millions of Indians her age.

She enrolled four years ago on a physiotherapy course in Dehradun, a city in the foothills of the Himalayas, and was doing an internship at a Delhi hospital when she was fatally attacked on board a bus in December last year.

Her father, a baggage handler at the capital's airport who earned $200 a month, had sold plots of land in the old family home in Uttar Pradesh to pay for her course in the hope of producing the family's first professional.

To help with the costs and give her financial independence -- for clothes, eating out and the fateful cinema trip that would lead to her death -- she worked nights at an outsourcing firm and gave private tuition to school children.

"She slept for three hours and we felt that she would faint in the classroom but she refused to rest," said Sheen Kaur, one of her roommates at the Sai Institute of Paramedical and Allied Sciences in Dehradun.

In a cruel twist, the marks from her final exams were published shortly after her death in a Singapore hospital on December 29, showing she had achieved first-class exam results.

M.C. Mishra, a surgeon who treated her in Delhi after the attack before she was flown to the Singapore hospital where she died, recalled how her ambition never wavered even at the last.

"She was really strong and she really was determined to recover... she said 'I will finish my course'. You could see how determined she was," he told the local CNN-IBN news channel.

Originally from Balia village in the impoverished northern state of Uttar Pradesh, the girl's family -- including two younger brothers -- live in a downtrodden part of the capital inhabited mostly by labourers.

During her course, friends say she transformed from a shy teenager to an active participant in college, helping to organise social events and choreograph dances.

In New Delhi, she would often meet up with the male IT worker five years her senior with whom she went to the cinema on the night of the December 16 attack that shook India.

Some friends say they planned to marry, but he has largely declined to speak about the relationship, stating that he "liked her and enjoyed being with her". The victim's father has denied suggestions the couple were set to wed.

The companion witnessed the brutal gang rape after being beaten by the attackers, later helping to identify the culprits in a police line-up and testifying against them in court.

He said he admired his dead friend's courage and ability to smile even in the worst situations.

"She had the magic to make everyone happy. Even when she was in the hospital, she asked me to wear a new shirt and said I looked very smart," he told AFP in an interview.

Despite the attention and relentless media coverage of the case, journalists in India have refrained from naming the dead woman in accordance with the law, using the pseudonym "Nirbhaya" (meaning 'Fearless' or 'Braveheart') instead.

"My daughter is dead but she fought till the very end. She is an inspiration for millions of other women who are fighting against sex crimes," her mother told AFP at the family house.

In March, the US posthumously honoured her with the International Women of Courage award.

"Her bravery inspired millions of men and women to come together with a simple message: 'No more'," US Secretary of State John Kerry told a ceremony in Washington.