Hassan Rouhani, Iran's moderate president-elect who shoulders the burden of great expectations, chose a key as his campaign symbol. His government of "wisdom and hope" would use it to unlock Iran's many problems.
One twist of the key could help reboot the flailing, sanctions-strapped economy. Another could ease strained relations with Iran's Arab neighbours and the West. And a final turn could unlock the door to stalled nuclear negotiations with world powers, he intimated at press conferences and during presidential debates.
"The first lock has been opened," Mr Rouhani declared after his unexpected victory over hardline candidates last month that prompted huge street celebrations.
Many supporters also want the key used in a literal sense when he takes office in early August, to release an estimated 300 to 400 political prisoners in Tehran's notorious Evin prison, including about 30 to 50 women.
But most of all they want Mr Rouhani to deliver on a promise to release the reformist leaders Mir-Hossein Mousavi and Mehdi Karrubi from more than two years of house arrest.
The two Green Movement leaders were candidates in the 2009 presidential elections who condemned Mahmoud Ahmadinejad's re-election as fraudulent, igniting months of huge street protests that were brutally crushed. Millions of Iranians believe Mr Mousavi was the real winner of that "stolen" election.
He and Mr Karrubi were put under house arrest in early 2011 after calling on Iranians to demonstrate in support of pro-reform protests in Egypt and Tunisia. Mr Mousavi's feisty wife, Zahra Rahnavard, is being held with him.
Mr Rouhani's supporters constantly chanted for their release at his campaign rallies. When he won, jubilant crowds shouted: "Mousavi, Mousavi, congratulations on your victory."
Days after being elected, Mr Rouhani was challenged at a news conference about his promise to free the reformist leaders. He urged patience, pointing out that it was "not all up to the president".
The centres of power behind the repression of the past four years - the judiciary, the intelligence ministry and the Revolutionary Guards - are outside Mr Rouhani's authority and directly under Iran's unelected supreme leader, Ayatollah Ali Khamenei.
Mr Rouhani, however, said he was "very hopeful that the atmosphere will change" to favour meeting many of the demands that are being put forward.
Drewery Dyke, an Iran expert at Amnesty International, said that "while the president's power is constricted, the presidency and the important mandate he achieved have a huge role in setting the mood music". And "the mood Rouhani is creating is a positive one".
Iran's new president has called for an end to government interference in people's private lives, an easing of the "security atmosphere", greater freedom of expression and less state control of the internet. He also plans to issue a "civil rights charter" that calls for equality of all citizens regardless of race, religion or gender.
There are grounds for hope that Mr Rouhani, a mid-ranking cleric, will be able to deliver on some fronts: despite his liberal stance, he is a long-serving and trusted regime insider.
Mr Khamenei has endorsed his election victory, which conferred some much-needed legitimacy on the regime following the debacle of the 2009 election.
And Mr Rouhani has the backing of two influential former presidents, Akbar Hashemi Rafsanjani and Mohammad Khatami.
Even so, Iran's new president will have to step gingerly, and within his mandate, given potential opposition from disgruntled hardliners who failed to secure the presidency for one of their own.
While Mr Rouhani has signalled he wants the release of the reformist leaders, he avoided explicitly naming them during his election campaign. This was seen as a sign of caution but also of his understanding of the realpolitik in Iran. The release of prisoners is decided by the judiciary, whose head is appointed by Ayatollah Khamenei.
Some experts supect that Mr Rouhani might show his commitment to freeing political prisoners by first attempting to release less controversial figures than Mr Mousavi and Mr Kerrubi, whom hardliners have accused of "sedition".
"That would be a less risky strategy for the new president," said a western diplomat.
So far, the envoy said: "There are positive signs from Mr Rouhani on the human rights front. But as with the nuclear file we'll be waiting to see if there's real progress after his inauguration next month."
Hadi Ghaemi, the New York-based director of the International Campaign for Human Rights in Iran, pointed out that Mr Rouhani has a "huge popular mandate" was "a skilful negotiator, conciliator and master of persuasion".
"If he focuses his leverage, both in private and in public, he can succeed in gaining the release of Mousavi, Karrubi and other political prisoners," Mr Ghaemi said.
Mr Mousavi's case is particularly pressing because he suffers from a serious heart ailment and, according to rights activists, has been denied regular medical check-ups.
Another early test for Mr Rouhani will be whether he can restore a measure of freedom on campuses when universities reopen in September. "Will student activists be released, will students groups be allowed to re-form officially and will a ban on their publications be lifted?" asked Mr Dyke of Amnesty International. "For us, that will be an important barometer of change."