Home VIP
VIP >  Presentation >  Introduction

VIP quasi zero-knowledge protocol

Challenge-response authentication

Many authentication schemes rely on challenge-response protocols. For instance, in most Internet banking applications, the server authenticates a client by asking him the response to a given challenge. For security purposes, this response is often computed by a tamper-resistant hardware token.

Leakage of sensitive data

However, tokens might store, or have access to, sensitive personal information. For example, the SuisseID card contains a highly sensitive private key used to generate qualified digital signatures; other tokens, like the AXSionics card, know or have access to biometric data, etc. Our proof-of-concept illustrates how easy it would be to (mis)use the response as a covert channel allowing sensitive information to leak from the token to a remote server without the user being even aware of this attack.

Enhancing the existing protocol

  • How to circumvent this threat for both security and privacy?
  • How could an honest token provider easily convince the bank and its customers that the produced tokens work as expected and cannot leak hidden information to the remote server?
  • How does a bank easily prove to its customers that its server is unable to harvest any sensitive information during the authentication protocol?

The VIP quasi zero-knowledge protocol brings an efficient solution to these questions, that is both easy to implement and inexpensive to deploy.

To top

Contact information

David-Olivier Jaquet-Chiffelle

Bern University of Applied Sciences – Engineering and Information Technology
P.O. Box 1180
CH-2501 Biel/Bienne


Phone: +41 32 321 62 66
Opens window for sending emailE-mail

Presentation leaflet

Download PDF document:


1.5 M