For the second time in as many weeks, a senior U.S. government official has warned that widespread use of encryption could harm investigations.
In a speech to the Global Alliance Conference Against Child Sexual Abuse Online conference in Washington, D.C., U.S. Attorney General Eric Holder said it's "worrisome" that companies are introducing systems that thwart the ability of law enforcement to quickly access a smartphone when a child is in danger.
"We would hope that technology companies would be willing to work with us to ensure that law enforcement retains the ability, with court-authorization, to lawfully obtain information in the course of an investigation, such as catching kidnappers and sexual predators," he said, according to a transcript provided by the U.S. Department of Justice.
"It is fully possible to permit law enforcement to do its job while still adequately protecting personal privacy," he said.
Holder's remarks echo those made last week by FBI Director James Comey, who told reporters that quick access by law enforcement to the contents of a smartphone could save lives in some kidnapping and terrorism cases.
The warnings come as Apple and Google are rolling out capabilities that enable millions of smartphone users to protect information on their devices so that no one, aside from someone in possession of a password, can access the data. Even the OS makers and phone companies won't have access.
Apple's iOS 8 allows users to encrypt some information on their phones while the next version of Google's Android OS, Android L, will enable full-phone encryption by default.
Carney accused smartphone companies of offering encryption as "something expressly to allow people to place themselves beyond the law."
Some see the government requests as not without irony. Interest in encryption has been heightened by revelations from former U.S. National Security Agency contractor Edward Snowden that several U.S. government programs are sucking up details on the communications of millions of people.
Martyn Williams covers mobile telecoms, Silicon Valley and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn's e-mail address is firstname.lastname@example.org