Cellphones. Credit cards. FasTrak devices.
All of these electronic tools, which Americans rely on every day, contain data that can be collected by authorities and used to weave a story, true or not.
That was the theme of a talk at Sonoma State University by Jacob Appelbaum, a staff research scientist at the University of Washington, and the only known American to have volunteered for WikiLeaks.
The computer security expert grew up in Santa Rosa, where he learned much of the programming and hacking skills that propelled him to notoriety and made him the subject of a government investigation.
In his Thursday speech to SSU's Computer Science Colloquium, Appelbaum also discussed the state of censorship in the U.S. and abroad.
"We don't have anonymity," Appelbaum said. "We have the ability to be targeted in all the things that we do, and basically any communication that we have.
"Raise your hand if you sent a text message this morning?" Appelbaum asked. "Who here pays their cellphone with a credit card? How hard do you think that it would be . . . to trace all of the things that you do?"
Many people have Facebook profiles, Twitter accounts and a cellphone history that tracks the top 10 people they call the most, but they don't think they're going to be the target of surveillance because they assume they're not very special, he said.
"The crazy way that surveillance happens now, is that everyone gets surveilled by default, to different degrees," Appelbaum said. "And then later, when you do something that attracts some attention, they go back and look through all the data they've collected."
He should know. Appelbaum was the target of government surveillance when Santa Rosa Internet service provider Sonic.net was ordered last spring to disclose data including all of the email addresses that he had communicated with since 2009. The company unsuccessfully fought the order in court.
Appelbaum said he takes extra measures to protect his privacy. He has a collection of anonymous SIM cards -- a type of memory device for cellphones -- in his backpack, and carries cash, even though cash has serial numbers that can be traced to ATM machines, he said.
"Sonic can't give up your information if they don't have it in the first place," he said.
Appelbaum also is a spokesman and developer for The Tor Project, which develops computer systems designed to protect Internet privacy. Tor was originally developed and deployed by the U.S. Naval Research Laboratory, and Appelbaum has traveled throughout the world to explain how it is used and why online anonymity matters.
On Thursday in an SSU classroom, Appelbaum spoke to about 70 computer science students, professors, journalists and personal friends that he knew from the North Bay Linux Users Group and his early programming days. He called on the students to create computer systems that are fundamentally designed to protect users' privacy.
Appelbaum discussed serious topics, including the role that American companies have played in providing software to countries that censor and track Internet traffic.
But he kept the tone light, evoking laughs as he raced through a detailed presentation for an hour.
He encouraged attendees to read "IBM and The Holocaust," a book by investigative author Edwin Black that says that IBM helped German authorities organize the Holocaust by using the company's punch card system, a precursor to the modern computer.