Edward Snowden speaks during an interview in Hong Kong. Snowden, a 29-year-old former technical assistant for the CIA, revealed details of top-secret surveillance conducted by the United States.The Guardian via Getty Images

Recent disclosures concerning the National Security Agency -- and its secret program to collect phone call data on millions of Americans -- have generated a storm of controversy. Legislators are lining up on each side of the issue, and a recent report from NPR suggests a broader cultural reaction to the news: Sales of George Orwell's novel "1984" have spiked 6,000 percent since the story broke, as media commentators liken the scandal to Orwell's depiction of a future police state.

The term "police state" is a little tricky, but it generally suggests a system of repressive government control where law is derived from executive power, with widespread state surveillance and suppression of free speech. Here are 10 signs -- from history and recent headlines -- that you're living in a police state, or that your country may be headed in that direction.

Pussy Riot band member Nadia Tolokonnikova looks out from a holding cell during a court hearing in the town of Zubova Polyana April 26, 2013.Mikhail Voskresensky/Corbis

The Russian punk band and activist collective known as Pussy Riot made headlines last year when three group members -- Yekaterina Samutsevich, Nadezhda Tolokonnikova and Maria Alyokhina -- were arrested and imprisoned after staging a political protest in Moscow. Two of the women are currently serving out sentences in the ominously named penal colonies IK-14 and IK-32.

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You may be living in a police state if your leader -- or his brother, or his son -- has been in power for 40 or 50 years. North Korea's Kim Il-Sung ran the country, under various titles, from its establishment in 1948 until his death in 1994. His son Kim Jong-Il took over from 1994 to 2011. And, of course, grandson Kim Jong-Un is in charge now. Cuba's Fidel Castro led the country from 1959 to 2011, then handed the reins off to his brother Raul Castro. There are many more examples: Supreme Leader of Iran Ali Khameni has been in power since 1981; Zimbabwe's Robert Mugabe since 1980; and Libya's Moammar Gadhafi had a 41-year run before his dramatic ouster in 2011.

Chinese artist Ai WeiWei poses for a portrait in one of the sleeping rooms for his live-exhibits at the "documenta" 12 international art show in Kassel, Germany.Kai Pfaffenbach/Corbis

In the international art world, Chinese artist Ai Weiwei is a giant. His sculptures and installations are exhibited worldwide, and he was one of China's homegrown heroes during the 2008 Beijing Olympics -- he helped design the famous “Bird's Nest" stadium. But he's also been highly and publicly critical of the Chinese government. In 2011, Weiwei was arrested in Beijing and essentially disappeared for three months. When he was released, Weiwei called his detention "hellish," but also said that he was forbidden from discussing anything about the matter in public. Weiwei's ordeal is chronicled in the excellent documentary "Ai Weiwei: Never Sorry."

A restroom sign in 1988 in Cape Town, South AfricaDave G. Houser/Corbis

While nominally a democracy, South Africa in the apartheid era systemically excluded the participation of the vast majority of its people. In 1948, legislation classified all inhabitants into four ethnic groups, and in 1970 political representation for all non-white people was abolished completely. Blacks were assigned to self-governing "homelands" and virtually every aspect of South African society was segregated. In 1990, President F.W. de Klerk began the process of dismantling apartheid and in 1994 a new untiy government was formed with Nelson Mandela as president.

A photo taken on Dec. 12, 2012 shows TV news in Pyongyang, the Democratic People's Republic of Korea (DPRK).Zhang Li/Corbis

North Korea's constitution guarantees freedom of the press. But then again, that document promises a lot of things. In practice, the government has near-complete control over all forms of mass media. The Korean Central News Agency is entirely controlled by the government, and provides all information to the nation's media outlets. The international watchdog group Reporters Without Borders ranks North Korea's freedom of the press as 178th, out of 179 countries. (Number 179? Eritrea.)

People look at computer screens inside an internet cafe in Xining, northwestern China's Qinghai province.Simon Zo/Corbis

Over the years, Chinese authorities have erected a massive structure of policies and technologies known as the Great Firewall of China. It's generally considered the biggest and most effective censorship apparatus in the world. Authorities use firewalls and proxy servers at the gateways where Chinese Internet traffic passes in and out of the country. They also use URL and website-scanning software to block access to certain online material or keywords -- for instance, "Tiananmen Square." State-run social media services have been deployed to emulate and replace Facebook and Twitter.

Anti-government graffiti in 1990 on a wall at the East German secret police headquarters (Stasi) calls for "Psychotherapy for public servants."Owen Franken/Corbis

The official state security service of East Germany during the Cold War era, the Stasi was renown as perhaps the most effective intelligence and secret police agency in history. The Stasi employed a massive network of secret informants in all areas of society. Official records suggest that at one point, around 200,000 citizens -- 3 percent of East Germany's total population -- were paid Stasi informants. The famous German actor Ulrich Muhe -- under constant surveillance during the Stasi era -- later found out his that wife was secretly a Stasi informant. He made a great movie out of it, the 2006 oscar winner "The Lives of Others."

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The research institute Freedom House publishes a yearly survey called "Freedom in the World," which attempts gauge relative degrees of political freedom in every nation on the planet. As part of last year's report, the group issued "Worst of the Worst 2012: The World's Most Repressive Societies." Nine countries were identified as being the world's worst human rights abusers in calendar year 2011: Equatorial Guinea, Eritrea, North Korea, Saudi Arabia, Somalia, Sudan, Syria, Turkmenistan and Uzbekistan.

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Government use of electronic surveillance is one of the danger zones that spook those afraid of a police state. In recent years, the United Kingdom has come under criticism -- from its own citizens -- that the country is fast becoming a surveillance society. The U.K. is certainly no police state, but both the government and private companies make heavy use of closed-circuit security camera, especially in cities. The research group Surveillance Studies Network has ranked Britain as the worst offender among Western industrialized nations. The U.K. certainly isn't alone in this regard. In a 2007 study, Privacy International called out eight countries for being "endemic surveillance societies: China, Malysia, Russia, Singapore, the U.K., Taiwan, Thailand and the United States.

Chairman and Vice Chairman of the U.S. Senate Select Committee on Intelligence, Sen. Dianne Feinstein and U.S. Sen. Saxby Chambliss, speak to the press about reports that the National Security Agency collected phone records.Alex Wong/Getty Images

Mere hours after the disclosure of the NSA phone data program, yet another top secret initiative was uncovered: The federal government has been secretly collecting information on foreigners overseas by working with the nation's largest Internet companies like Google, Facebook and Apple. U.S. director of national intelligence James Clapper confirmed the reports but was quick to point out that the secret program, called Prism, was approved by Congress. And that it minimizes the collection and retention of information “incidentally acquired" about American citizens. Oh, good. So long as they're minimizing it.