It is “completely unacceptable,” said a British official, that a message sent by the man who killed four people in an attack near Britain's Parliament last week cannot be retrieved because it was sent using an encrypted service that shields all correspondence from authorities.
British Home Secretary Amber Rudd said on Sunday that end-to-end encrypted messages create a "secret place for terrorists to communicate,” threatening public safety and national security.
The comments came after British security officials noted that Khalid Masood, the man responsible for Wednesday's knife attack, used WhatsApp, a Facebook-owned messaging service just minutes before stabbing dozens of people Wednesday in London. Police responding to the attack shot him dead at the scene.
Authorities are continuing to investigate the incident, searching for others who may have links to Mr. Masood and seeking to uncover a motive behind the attack. But restrictions from WhatsApp that create an end-to-end encryption barrier make it impossible for third parties to retrieve the messages.
Balancing privacy concerns with those of national security and public safety have proved tricky as smartphones and apps provide new avenues for secret messaging. Apple found itself ensnarled in the debate last year as authorities sought to unlock the phones of the San Bernardino shooters, who killed 14 people at a center for adults with disabilities in Dec. 2015. Eventually, the FBI accessed the devices without Apple’s assistance.
While authorities sometimes argue that accessing the information is the best way to locate other suspects and intercept future attacks, privacy advocates say that giving officials access to personal correspondence could create a surveillance state. Under encrypted options, the government, hackers, and the tech companies themselves are unable to access messages sent between parties.
And encrypted messaging is becoming a more popular feature, with other services opting to roll out new features. With that, it’s unlikely tech companies will favor creating a backdoor option for authorities to access information.
“We need to make sure organizations like WhatsApp, and there are plenty of others like that, don't provide a secret place for terrorists to communicate with each other," Ms. Rudd told the BBC's Andrew Marr show. "We need to make sure that our intelligence services have the ability to get into situations like encrypted WhatsApp."
She argued that authorities should be able to access encrypted services with a warrant, similarly to how they can listen in on telephone calls or intercept letters with legal permission.
But not everyone agrees. On Monday, the European Union pushed back against those calls, saying officials needed to weigh security concerns against privacy rights.
"There is a fine line here,” Maltese Interior Minister Carmelo Abela said Monday. “We need to of course protect the privacy of the people but we also have to protect the security of the people."
Police arrested a man in Birmingham, England, where Masood had lived, over the weekend. Authorities now have two men in custody they believe are linked to the attack.
This report contains material from the Associated Press.