Karen Pickett has long assumed that her home phone is tapped. She's an EarthFirst activist in Berkeley, and she says she never uses her phone when planning certain kinds of protest actions.
"Even [with] something as tame as a banner hanging, the element of surprise is everything," she says. "It's generally safer to use payphones and that sort of thing."
But taking your sensitive conversations to a payphone is old school. Pickett admits she hasn't thought about the possibility that the government doesn't care so much about what she's saying as it cares about whom she's calling on a regular basis -- even for innocuous conversations.
Reporter Bob Hensley has thought about is. A free-lancer for NPR, he's been developing sources in the Muslim community in Lodi, Cali. He says that a recent report in USA Today about call pattern analysis almost cost him one of his best sources.
"His concern was that he had given me numbers of people who were sympathetic, and he assumed I was calling them," Hensley says. "He was afraid that if my number got kicked out, then his number would be included."
Henlsey has stopped calling the source from his house.
"What I decided to do was go out and buy with cash a pre-paid phone card," Hensley says. "Then through other means, [I'd] arrange to call them, where they're receiving the call on a payphone."
Is a pre-paid phone card the solution? Not necessarily, says computer security and privacy expert Richard Smith. He notes that calling cards have an ID number associated with them.
"As you made phone calls against that card, they'd get recorded in a database someplace," Smith says. He says that calling card companies could theoretically track both the phone number you are calling from and the number you are dialing.
"It's really a policy decision of the company of what they keep in their database," Smith says.
Scrambling Net Calls
Some privacy advocates like voice-over-Internet phones. Phil Zimmermann, inventor of the PGP encryption system for e-mail, has now created a scrambler for people who talk over the Internet -- a bit of software he calls "Zfone." But he cautions that it protects only the content of the call.
"If your opponent is in a position to observe the servers that broker the phone calls, then they're going to know who's talking to whom," Zimmermann says.
The Disposable Solution
In California, reporter Bob Hensley says another one of his Muslim sources has taken to using what he calls a "disposable cell phone" -- a phone not purchased under his own name, and recharged with pre-paid cards. But Matthew Aid, an expert on NSA methods, says he doubts that would work very long.
"High-tech tools only tend to attract attention to what you're doing," Aid says.
The NSA won't immediately know who's using that no-name cell phone, but it will want to find out. Aid is writing a history of the NSA and often has discreet conversations with government employees. He never calls them directly. He sets up face-to-face meetings -- but is cagey about how.
"I'd prefer not to get into the specifics, because living in Washington, there are people who would like to know how these things work," Aid says.
"The sad thing is, it's become much harder to do this work because of the all-pervasive fear that permeates this town."
Few Taking Protective Steps
Still, the number of people in America taking steps to hide their phone calls is minuscule. Even most investigative reporters approached by NPR say they haven't really changed their communications habits.
You can find a list of privacy and encryption techniques at a Web page run by the Electronic Privacy Information Center. But even the director of that organization says he himself doesn't use the techniques -- in part, he says, because he'd rather not become what he calls a "privacy survivalist."