Vocal Passphrase

Improved call center safety with
the help of effective fraud & identity
theft protection

SESTEK Vocal Passphrase is a biometric speaker authentication system that answers the security needs of institutions by providing high levels of security measures and reducing call center costs. With its language- and accent-independent structure, Vocal Passphrase provides a secure and efficient method for verifying a speaker’s identity while combatting fraud and identity theft.

SESTEK Vocal Passphrase, SESTEK’s voice biometrics software, is based upon voice verification and voice identification technologies. With the help of SESTEK Vocal Passphrase, callers can securely access contact centers using their voiceprints instead of losing time dealing with conventional security measures, such as PINs, passwords and challenge questions. In order to use this speaker verification technology, callers first enroll in the system by creating their individual voiceprints. Once the vocal password is created, callers can enter the system by simply speaking the passphrase.

As a result of the accurate speaker recognition and caller authentication that SESTEK Vocal Passphrase provides, call centers enjoy increased efficiency and enhanced customer experience.

With full confidence in its technology and know-how in voice biometrics, SESTEK can perform the proof-of-concept installments free of charge in medium- and large-scale call centers.


  • Improved call center safety with the help of effective fraud and identity theft protection
  • An enhanced security solution that can be used in two-factor and multi-factor authentication
  • Reduced costs in contact centers as a result of reduced call duration and increased automation
  • Enhanced customer experience with secure biometric voice authentication and the elimination of time-consuming authentication questions


  • Language- and accent-independent
  • Easy integration with web service interface
  • Low false acceptance and rejection rates
  • Active directory integration
  • Playback detection
  • Gender detection

Success Story

In 2011, SESTEK Vocal Passphrase was deployed at the call center of Turkish Telecom-Mobile. Before the implementation of Vocal Passphrase, Turkish Telecom-Mobile’s call center used to verify identities of customers via a manual agent-assisted security procedure. Since the call center receives thousands of calls each day, this manual identity verification method was causing considerable loss of time, increased costs and customer dissatisfaction. After the implementation of Vocal Passphrase, customers began to use voiceprints to access Turkish Telecom-Mobile’s call center. In the first year, the number of registered voiceprints reached 1 million, and the number of enrolled voiceprints is increasing each day. Call duration has been shortened by 15 seconds, with more than $400.000 in annual savings. Today, 1 out of every 5 callers to the Turkish Telecom-Mobile contact center uses the Vocal Passphrase procedure, and SESTEK’s implementation in Turkish Telecom-Mobile has become one of the top 5 applications in the global market in terms of its enrollment size, with approximately 4 million users.

In 2012, SESTEK Vocal Passphrase was deployed at the call center of DenizBank, one of the leading banks in Turkey. After the implementation, customers began to use voiceprints to access the call center. As a result of the accurate biometric identification that the system provides, callers could now complete their transactions securely and easily. DenizBank Vocal Passphrase implementation was the first voice verification project in the Turkish banking industry.

To learn more about our successful Vocal Passphrase projects, check out our case studies.

SESTEK is featured in DMG Consulting’s 2016 Voice Biometrics Product and Market Report. The report analyzes market trends and challenges. It reviews product innovation and competitive landscape. It also presents market activity data with five-year projections.

The report reviewed SESTEK Voice Biometrics technologies in terms of omni-channel capabilities, enrollment authentication methods, fraud/risk management approach, and value-added capabilities. SESTEK develops voice biometrics technologies with the aim of increasing efficiency by reducing costs and making life more convenient by providing practical solutions. To learn more about “The 2016 Voice Biometrics Product and Market Report,” please click here.