"I have indeed committed an unfailingly heinous offense," wrote Sánchez in her blog. "I have believed myself to be free."

Long lines were seen outside travel agencies and migration offices and even the U.S. Interests Section in Havana on the first day of a new law that makes it easier for Cubans to leave their country.

The Communist-run island has largely banned people from leaving for decades. Cubans could apply for passports to travel but also needed an exit visa from the government, which distributed them rarely.

In October the government abolished the requirement for the exit visa. But as Sánchez noted, the government retained the power to deny travel to people it deems to be national security risks as well as those considered vital to the revolution, such as scientists and engineers.

Sánchez has long been considered one of those risks.

In a recent interview she gave at her Havana apartment, she sat at her dining room table with two Cuban human rights activists who were taking notes from a lecture she gives on how to use databases to circumvent Cuban authorities' strict controls.

A computer scientist and activist, Sánchez was wearing an oversized, striped shirt, her dark hair flowing down below the waist of her thin figure, a consequence she says of growing up when food in Cuba was scarce during the 1990s.

Sánchez, 37, is one of Cuba's most well known opposition figures, having won numerous journalism awards and been named on Time magazine's 100 Most Influential list. This is despite the difficulty of Internet access on the island, though it has little to do with lagging technology, she said.

In 2011, Venezuela confirmed that an undersea fiber-optic cable between the two countries has been laid and was fully operational. While some pro-democracy activists are able to communicate via Twitter and other social media tools, the government is restricting Internet access throughout Cuba to prevent problems in the country from being aired in a free forum.

"Those in North Africa have achieved the Arab Spring with a cellphone in their hand, on it a connection to Facebook and Twitter," she told USA TODAY as she sat in front of her laptop computer, which had no Internet connection. "We don't have the same access to technology.

"This is a country where political parties are banned," she said. "People can't meet in a public place to debate political ideas in a free way. The Internet can allow this and so the government is scared."

Sánchez has been able to circumvent the authorities, however.

"Since I was very young, I liked to pull things apart, watches, old radios for example, to see inside," she said.

Sánchez assembled her first computer in 1994. The Cuban black market was Sánchez's source for the parts.

It is possible to buy a new iPhone 5 in Havana for around $800, Apple sells them in the USA starting at $199. The price is prohibitively expensive for the average Cuban, who earns around $18 a month. Sánchez's iPhone sits on her table.

Still, to publish a blog in a Communist country where access to the Internet is subject to government restriction takes special tricks. Sánchez would go into hotels posing as a tourist, using a few German or English words she knew, and plug into an Internet connection. Such subterfuge became more difficult as she and the blog became better known and a compilation of its posts published in an English-language book, Havana Real. But technology keeps offering new ways around the Castro regime.

"You cannot imagine how much information there is, terabytes through pen drives and hard disks. A society so closed off has developed an ingenious underground mechanism to pass on data," she said.