"I believe what you do on your cellphone is none of their damn business," Paul declared several times during the speech, earning applause.
Much of Paul's speech focused on Edward Snowden, the former government contractor who leaked classified information about the NSA's secret wiretapping and telephone monitoring programs to The Washington Post and other media outlets -- prompting a renewed focus by the American public and lawmakers on how much surveillance executive branch agencies are conducting on Americans.
Paul seemed to at times defend Snowden's leaks and said that Director of National Intelligence James Clapper committed a felony when he testified before a congressional committee that the NSA was not using warrants to secure the mass collection of Americans' phone records.
"Edward Snowden did break the law, but so did James Clapper. I don't think that there has been enough criticism of Clapper," Paul said, later adding: "History will decide who is hero and who is villain. Clapper lied in the name of secrecy. Snowden told truth in the name of privacy."
Asked later if Clapper should be sent to prison, Paul responded: "I think Clapper should be tried for perjury."
Paul also praised Sen. Dianne Feinstein (D-Calif.), who last week took to the Senate floor and accused the CIA of illegally monitoring computers used by the Senate Intelligence Committee to investigate the agency's torture practices.
The speech was the latest in a series by Paul in which he has railed about government surveillance and called for a renewed bipartisan focus on civil liberties. In his recent speeches, Paul has notably included references to the civil rights movement and racial injustices in American history, and his speech at Berkeley follows an appearance last year at Howard University, a historically black university in Washington.
"J. Edgar Hoover's illegal spying on MLK and others in the civil rights movement should give us all pause," Paul declared.
Asked if the appearances were part of a political strategy to better position himself for a 2016 presidential run, Paul replied with a coy "maybe" before repeating calls he's made previously for a reinvention of the Republican Party, comparing the GOP to Domino's pizza -- "our crust sucks."
"The Republican Party, they need to either evolve, adapt or die," Paul said. "We need a different Republican Party."
An earlier version of this post misspelled the first name of Sen. Dianne Feinstein (D-Calif.). It has been corrected.