Government surveillance of telephone records and conversations in the name of national security has long been controversial.
The debate, which dates back decades, is back in the news with recent revelations that the U.S. government is collecting telephone records in the United States and some Internet traffic overseas.
Here's a primer on what the government is getting, how it affects you and what the legal debate is all about:
I live in the United States. What kinds of records is the government collecting on me?
U.S. officials have acknowledged collecting domestic telephone records containing the time and date of calls and telephone numbers involved. A secret court order published by The Guardian newspaper also indicates the government is getting rough location information and details that would identify the specific handsets used to make mobile calls.
That court order names Verizon Business Network Services, but analysts say similar orders are likely in effect for all U.S. carriers, meaning the government has logs of most, if not all, telephone calls.
The Wall Street Journal, citing people familiar with NSA activities, reported Friday that the agency has also collected credit card records. But the newspaper couldn't say if that collection effort is continuing or was a one-time effort.
I live overseas. What might the United States have?
If you're a United States citizen or permanent resident living or traveling overseas, the government says it's not collecting anything on you, If it does, the government says, it's incidental and the resulting data is kept under strict controls.
But the picture could be different for citizens of other nations living outside the United States.
Director of National Intelligence James Clapper on Thursday indirectly confirmed a program to collect data generated by overseas customers of some of the largest internet services companies in the world, including Microsoft, Yahoo, Google and Apple.
Clapper's statement came Thursday in response to stories in the Washington Post and The Guardian newspaper Thursday reporting the existence of a program called PRISM. The program is designed to collect "audio and video chats, photographs, e-mails, documents" and other materials, The Post reported.
The Wall Street Journal, however, said the monitoring doesn't include the contents of messages.
Is the government listening to my phone calls?
Clapper says it's not.
What happens to the records?
The telephone records go into a database, where they can't be accessed unless a judge gives the go-ahead in a national-security investigation, Clapper said.
Sen. Dianne Feinstein, chairwoman of the Senate Intelligence Committee, said Thursday that the records can't be accessed without "reasonable and articulable suspicion" that they're relevant to terrorist activity.
It's less clear what happens to the Internet monitoring data, but Clapper said it's "used to protect our nation from a wide variety of threats."
Why does the government need this information?
Access to such information "allows counterterrorism personnel to discover whether known or suspected terrorists have been in contact with other persons who may be engaged in terrorist activities, particularly people located inside the United States," a senior Obama administration official said Thursday.
Clapper said Thursday that the telephone records allow analysts to "make connections related to terrorist activities over time."
The Internet data collected overseas "is among the most important and valuable foreign intelligence information we collect, and is used to protect our nation from a wide variety of threats," he said.
Who approved these programs?
Both programs have been approved by all three branches of government, officials say.