Voice Biometrics for

Vocal Passphrase Case Study


“Denizbank implemented the first voice biometrics project in the Turkish banking industry”

All Thanks to Sestek Vocal Passphrase


The Need

Before the implementation of Sestek Vocal Passphrase, DenizBank-Sberbank’s call center verified customers’ identities via a manual agent-assisted procedure. Since banking transactions include personal data, which needs to be protected, detailed security procedures were applied. This manual identity verification processes caused time loss, increased operational costs and customer dissatisfaction.

The Implementation

A person’s voice is one of his or her most unique characteristics. Since it cannot be shared, copied or lost, it is a biometric property. Voice biometrics, which provides accurate and reliable authentication, is the only biometric security measure applicable to phone-based transactions. Sestek Vocal Passphrase is a biometric solution that answers the security needs of institutions by providing high levels of security, reducing call center costs and enhancing customers’ experience. This biometric speaker verification software was implemented at DenizBank-Sberbank’s call center in 2012. The system includes two steps: enrollment and verification. Enrollment requires users to create a vocal password by repeating a passphrase  three times. Once the user is enrolled, he or she can be verified by saying the same passphrase out loud once in each of  her subsequent calls.

The Results

Following the implementation of Sestek Vocal Passphrase, customers were able to reach the call center of DenizBank (Sberbank) easily by using their voice. Customers could complete banking transactions securely without losing time due to traditional security procedures. Denizbank Vocal Passphrase project includes the first voice verification implementation in the Turkish banking sector.

Sestek Vocal Passphrase

  • Biometric speaker authentication system
  • Language and accent-independent structure
  • Verifies speaker’s identity while also enabling protection against fraud and identity theft
  • Answers to security needs by providing high-level security measures and reducing call center costs

denizbank logo

  • DenizBank Financial Services Group consists of five domestic, three international financial subsidiaries, six domestic non-financial subsidiaries, and a branch in Bahrain.
  • In addition to the 713 domestic DenizBank branches, DenizBank AG have 43 branches in total.