Last week, Interpol held a final project review of its speaker identification system, a four-year, 10 million euro project that has recently come to completion. The Speaker Identification Integrated Project, what they call SiiP, marks a major development in the international expansion of voice biometrics for law enforcement uses — and raises red flags when it comes to privacy. Speaker identification works by taking samples of a known voice, capturing its unique and behavioral features, and then turning these features into an algorithmic template that’s known as a voice print or voice model. With enough voice prints and samples collected in its global audio database, Interpol’s speaker identification system will be able to upload an unknown voice and, regardless of the language it is speaking, match it to a list of likely candidates. SiiP’s database allow uploads and downloads of samples from 192 law enforcement agencies across the world. SiiP will join Interpol’s existing fingerprint and face databases, and its key advantage will be to facilitate a quick identification process — say, of a kidnapper making a phone call — even in the absence of other identifiers. The platform also boasts the ability to filter voice samples by gender, age, language, and accent. When the audio recordings are taken from similar acoustical environments, accuracy rates can be extremely high.

Speech recognition technologies can identify and tag individuals every time they open their mouths, effectively ending anonymity. As Interpol’s promotional video explains, departments using SiiP can upload intercepted phone calls and also search against voices on social media. SiiP’s database will include samples from YouTube, Facebook, publicly recorded conversations, voice-over-internet-protocol recordings, and other sources where individuals might not realize that their voices are being turned into biometric voice prints. “People choose to upload material online for various reasons, but I doubt it’s to let police and arms companies then enroll them into secret databases made available to police around the world,” explained Edin Omanovic, a surveillance expert at Privacy International. Cynthia Wong, a researcher at Human Rights Watch, warned that a broad mandate could lead to an ever-expanding collection. “There are many instances where we might consent to our voice being recorded for one purpose, but would object to using it for others, including using our voice to build and train a massive voice biometric database and recognition system,” she said. “Or perhaps we didn’t consent to our voice being recorded at all — perhaps our voice was secretly recorded or inadvertently caught in the background of a recording, but has now been placed in Interpol’s database.

SiiP’s database will include samples from YouTube, Facebook, publicly recorded conversations, and other sources where individuals might not realize that their voices are being turned into biometric voice prints.