http://dl.gi.de/handle/20.500.12116/20077 Thu, 23 Jul 2026 12:40:24 GMT 2026-07-23T12:40:24Z http://dl.gi.de/handle/20.500.12116/18566 The glass maze: hiding keys in spin glasses Trugenberger, Carlo A. Brömme, Arslan; Busch, Christoph Key-binding mechanisms allow to use one's biometric features as a universal digital key without having them ever stored anywhere. Security, ease of use and privacy concerns are addressed in one stroke. The best known proposal for such a mechanism, the Fingerprint Vault, treats biometric data as projections of a polynomial encoding the key. Its security is based on the difficulty of polynomial reconstruction. Here I propose a new key-binding mechanism based on associative pattern recall and making use of a totally different security principle, that of the difficulty of energy optimization of spin glasses. The idea is to exploit the mixed ferromagnetic and spin glass phase of the Hopfield neural network to encode the key as a local minimum configuration of the energy functional, ”lost” amidst the exponentially growing number of valleys and minima representing the spin glass. The correct fingerprint will be able to retrieve the key by dynamical evolution to the nearest attractor. Other fingerprints will be driven far away from the key. Known vulnerabilities of the Fingerprint Vault are eliminated by this new security principle. Sat, 01 Jan 2011 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/18566 2011-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/18565 Continuous speaker verification in realtime Kunz, Max; Kasper, Klaus; Reininger, Herbert; Möbius, Manuel; Ohms, Jonathan Brömme, Arslan; Busch, Christoph Biometric speaker verification deals with the recognition of voice and speech features to reliably identify a user and to offer him a comfortable alternative to knowledge-based authentication methods like passwords. As more and more personal data is saved on smartphones and other mobile devices, their security is in the focus of recent applications. Continuous Speaker Verification during smartphone phone calls offers a convenient way to improve the protection of these sensitive data. This paper describes an approach to realize a system for continuous speaker verification during an ongoing phone call. The aim of this research was to investigate the feasibility of such a system by creating a prototype. This prototype shows how it is possible to use existing technologies for speaker verification and speech recognition to compute segments of a continuous audio signal in real-time. In line with experiments, a simulation study was made in which 14 subjects first trained the system with a freely spoken text and then verified themselves afterwards. Ad- ditional intruder tests against all other profiles where also simulated. Sat, 01 Jan 2011 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/18565 2011-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/18560 BIOSIG 2011 – Proceedings of the Biometrics Special Interest Group Brömme, Arslan; Busch, Christoph Sat, 01 Jan 2011 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/18560 2011-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/18561 3D capturing of fingerprints – on the way to a contactless certified sensor Koller, Dieter; Walchshäusl, Leonard; Eggers, Georg; Neudel, Frank; Kursawe, Ulrich; Kühmstedt, Peter; Heinze, Matthias; Ramm, Roland; Bräuer-Burchard, Christian; Notni, Gunther; Kafka, Ricarda; Neubert, Ralf; Seibert, Helmut; Castro-Neves, Margarida; Nouak, Alexander Brömme, Arslan; Busch, Christoph The purpose of this paper is to describe the development and performance tests of a contact-free fingerprint sensor, TrueFinger3D (TF3D). This contactless fingerprint sensor is designed to be perfectly interoperable with fingerprint image data captured with contact-based sensors or ink pads. This is achieved by acquiring a 3D dataset of the fingertip together with the image of the papillary lines. Based on the 3D data, the papillary lines image can be processed to compensate perspective foreshortening or even emulate deformation effects caused with contact-based sensors. The 3D measurement mechanism and the image processing are described in detail. The resulting fingerprint images taken by the contactless sensor are then matched with images taken by regular contact-based fingerprint readers at different force levels. The comparison shows that the geometric distortion of our contactless sensor TF3D is comparable to that of contact-based sensors deployed under regular conditions. Our test also shows that contact-based sensors operated under irregular or strong force conditions suffer from a substantial performance degradation, not seen with the contactless sensor TF3D, which has perfect reproducibility. The results also indicate perfect interoperability of the TF3D with any contact-based data and should therefore entitle the sensor to a certification for governmental use. Sat, 01 Jan 2011 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/18561 2011-01-01T00:00:00Z