On any given evening Cairo's Tahrir Square creaks under the weight of its own recent history: trinket-sellers flog martyrs' pendants, veterans of the uprising hold up spent police bullets recovered from the ground, and an ad hoc street cinema screens YouTube compilations of demonstrators and security forces clashing under clouds of teargas. This is collective memory by the people, for the people – with no state functionaries around to curate what is remembered or forgotten.

"Egyptians are highly sensitive about official attempts to write history and create state-sponsored narratives about historical events," says Khaled Fahmy, one of the country's leading historians. "When Hosni Mubarak was vice-president in the 1970s he was himself on a government committee tasked with writing – or rather rewriting – the history of the 1952 revolution to suit the political purposes of the elite at that time. That's exactly the kind of thing we want to avoid."

Fahmy knows only too well about the inherent tension between acts of mass popular participation and official attempts to catalogue and record them. Less than a week after the fall of Mubarak, the professor received a phone call from the head of Egypt's national archives asking him to oversee a unique new project that would document the country's dramatic political and social upheaval this year and make it available for generations of Egyptians to come.

"I was initially very reluctant," says Fahmy. "I didn't want people to think we were producing one definitive narrative of the revolution. But then I started thinking about the possibilities, and suddenly I got excited."

And so the Committee to Document the 25th January Revolution was born. Staffed by volunteers and drawing on everything from official records and insurrectionary pamphlets to multimedia footage and updates on Twitter and Facebook, the project aims, in Fahmy's words, "to gather as much primary data on the revolution as possible and deposit it in the archives so that Egyptians now and in the future can construct their own narratives about this pivotal period."

The project will also collect hundreds of hours of recorded testimony from those involved in the struggle to bring down Mubarak – whether they supported the revolution or not.

It is an exercise fraught with difficulties, particularly at a time when the question of who gets to speak for the revolution is being bitterly contested on the streets of Cairo and elsewhere. "Documenting the revolution sounded like an easy thing, but what is the revolution?" asks Fahmy. "When did it start? When did it end? What constitutes participation in the revolution – is it only those who went down to Tahrir, or is it also the doctors who worked extra-long hours in their hospitals to treat the wounded? What about a police officer who fought the protesters – is he a part of the revolution or not?"

There is nothing academic or theoretical about those questions. Over the past five months the ruling military junta has sought to limit the scope of the revolution both rhetorically and legally, applying the term strictly to the 18 days of street demonstrations that led to Mubarak's resignation and contrasting those "selfless" protests with the "disruptive" and "self-interested" strikes and sit-ins held subsequently by workers and other groups demanding political change. This month has seen tens of thousands of protesters reoccupying Tahrir and other city centres around the country, arguing that the revolution has been hijacked by conservative forces and offering a powerful rejoinder to the army's claim that grassroots political struggle has now come to an end.

It is a conflict over ownership of the process of revolutionary change, one that has already brought violence back to Egypt's streets – and which Fahmy's project is wading straight into the middle of. On the day Fahmy met the Guardian, one of the committee's working groups had just decided to alter the "start date" of their enquiries – moving it from 14 January, the day the Tunisian president Zine al-Abidine Ben Ali was forced from office, back to June 2010 when the Alexandrian youth Khaled Said was killed in broad daylight by two police officers, an incident that mobilised many Egyptians against the Mubarak regime. The "finish date" of their project – the moment the committee formally considers the revolution to have ended – remains the most controversial of all, and is still up in the air.

"All the committee members, who range from activists to bloggers to academics, are politically conscious, and we're aware that making these sorts of decisions is problematic," insists Fahmy. "My own feeling is that the revolution is very much incomplete, and this second stage – which requires overcoming the army – may prove even more difficult than the battle to topple Mubarak."

But aside from reflecting the contested nature of post-Mubarak Egypt, Fahmy believes his historical committee has another, more subversive purpose. In common with most Arab countries, public access to official information in Egypt is almost nonexistent, with state archives buried beneath a musty web of security restrictions and a deeply entrenched government culture of destroying or hiding any records that could prove awkward. But Fahmy hopes this latest initiative could herald a fundamental change in the way Egyptians view their relationship with state information – and by extension, their relationship with the state itself.

"It is people who make history, not generals or leaders," says Fahmy. "But if it is the people who make history, then they should be the ones who write it and read it as well." From the very beginning he has insisted that all material collated by his committee must be publicly accessible to anyone on the internet. That decision breaks a mould of state secrecy that has prevailed for decades; today, anybody wishing to research 18th century Egyptian ports must still submit themselves first for interrogation at the ministry of defence.

"The question of access to information and archives is political, because reading history is interpreting history, and interpreting history is one way of making it," adds Fahmy. "Closing people off from the sources of their own history is an inherently political gesture, and equally opening that up is a political – even revolutionary – act."

Fahmy's committee is not the only group attempting to pry open a long-held tradition of official concealment. Within a few weeks of Mubarak's fall, protesters had ransacked the headquarters of Egypt's notorious state security service, looting thousands of classified documents and placing many of them online. Last month the country's first freedom of information law was drawn up, though there is no guarantee it will make it on to the statute books.

But despite all the institutional obstacles, Fahmy is certain that the size and nature of this year's revolt means there can be no going back to the days when Egyptians were severed from the deliberations and documents of those ruling in their name.

"This was a leaderless revolution, and one which came about through mass participation," he explains. "The way we write history now has to be part of the same process, and so does the way we access that history. That for me is as much a part of the revolution as anything else."

Remembering revolution: five additional projects attempting to archive Egypt's political upheaval

• Tahrir Documents Provides scans of dozens of printed leaflets that were circulated in the streets during the anti-Mubarak uprising, from religious tracts to lists of political demands.

• R-Shief An ambitious data-mining project that draws content from Twitter and hundreds of other websites documenting the Arab spring, and provides tool and visualisations to help analyse it.

• University on the Square A collection of revolutionary stories and memorabilia shared by the staff, students and alumni of the American University in Cairo.

• 25Leaks.com The definitive home of documents seized by protesters from state security headquarters in the aftermath of Mubarak being ousted. The site's creators have remained anonymous for their own safety.

• Memory of Modern Egypt An initiative in Arabic by the vast Bibliotheca Alexandrina on the Mediterranean coast that seeks to collate material on the revolution from across Egypt, including the stories of martyrs.