Declassified documents reveal the National Security Agency has been using secret “speaker recognition” technology to identify people by their unique “voiceprint” for more than a decade.
The NSA has been recording and gathering private phone calls for years, but it used to be difficult for the agency to identify unknown speakers. In the past, signals intelligence (SIGINT) transcribers worked on the same targets for years before they became familiar enough with a speaker’s unique voice to be able to verify their identity.
Now, the NSA is using more advanced computational systems developed by the Massachusetts Institute of Technology (MIT) in order to catch spies and terrorists, according to a declassified NSA document obtained by media outlet the Intercept.
The document describes how the NSA used the technology during Operation Iraqi Freedom to match an audio recording to former leader Saddam Hussein’s “voiceprint.” The NSA also used the technology to compare the voice of a captured suspect with previous audio recordings from terrorist Abu Hakim to confirm that the suspect was not a match.
In order to test their technology, analysts at the NSA compared old intercepts and audio files relating to Ron Pelton, a former NSA analyst who sold details about several secret US programs to the Soviet Union. At the time, the agency failed to identify Pelton through human voice identification. However, in 2006, the agency was able to automatically match Pelton’s voice using the technology.
“Had such technologies been available twenty years ago, early detection and apprehension could have been possible, reducing the considerable damage Pelton did to national security,” the document states.
According to the classified document, the NSA was able to automatically identify a Chinese speaker when they were speaking in English. The document states that voice recognition technologies were “rapidly becoming the standard in the Intelligence Community” more than a decade ago.
Civil liberties advocates are concerned that the technology could make it easier for the NSA to violate the privacy rights of American citizens.
“This creates a new intelligence capability and a new capability for abuse,” Timothy Edgar, a former White House adviser to the Director of National Intelligence, told the Intercept. “Our voice is traveling across all sorts of communication channels where we’re not there. In an age of mass surveillance, this kind of capability has profound implications for all of our privacy.”
Since a “voiceprint” is nearly impossible to change or disguise, privacy advocates also fear the NSA would be able to instantly locate and track anyone who can be heard by a microphone.
“There are microphones all around us all the time. We all carry around a microphone 24 hours a day, in the form of our cellphones,” Trevor Timm, executive director of the Freedom of the Press Foundation, told the Intercept. “And we know that there are ways for the government to hack into phones and computers to turn those devices on.”
Former NSA intelligence analyst, Edward Snowden added that the technology could even be used to track people down through other kinds of listening devices, including “a friend's laptop, the phone next to you on the train, that Amazon Echo on the shelf…”
Although the NSA has kept their voice-matching technology a secret, the Associated Press reported that Turkcell, the largest mobile phone company in Turkey, used a popular speech recognition technology to collect voice data from approximately 10 million customers in 2014.
In October, Human Rights Watch reported that the Chinese government has been gathering tens of thousands of “voice pattern” samples to establish a national voice biometric database and a program that can automatically identify voices in phone conversations.
Interpol also recently announced the Speaker Identification Integrated Project (SIIP), a speaker identification technology funded by the European Union, had passed its final field test.
The program, which began in 2014, was finally able to identify unknown speakers talking in different languages in November of last year.
The Senate recently voted to reauthorize Section 702 of the Foreign Intelligence Surveillance Act (FISA), permitting electronic surveillance of non-Americans. However, it has been shown that the NSA has also collected data on Americans during their surveillance.