Police agencies need access to digital information to solve crimes, and they don't otherwise track people, he added. "We don't monitor websites where people visit or aggregate data about people's personal health, wealth or shopping habits," Conley said. "That, frankly, is the purview of companies like Apple and Google."
Conley had harsh words for data collection by technology companies. "Their nominal commitment to privacy rights would be far more credible if they were forbidding themselves access to their customers' interests, search terms and consumer habits, but as we all know, they're taking full advantage of their customers' private data for commercial purposes," he added.
Other witnesses at the hearing said encryption workarounds would cause serious problems for technology vendors. U.S. smartphone apps that allow back doors would likely be banned in many European countries, said Jon Potter, president of the Application Developers Alliance. In addition, if the U.S. demands encryption back doors, other countries will follow suit, he said.
"Nearly every digital business wants to be global," he said. "But mandatory government back doors may spark a trade war and imprison businesses in their home country."
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