Logo des Repositoriums

Auflistung nach Autor:in "Merkle, Johannes"

1 - 10 von 12
  • Konferenzbeitrag
    Correlation-resistant fuzzy vault for fingerprints
    (Sicherheit 2016 - Sicherheit, Schutz und Zuverlässigkeit, 2016) Butt, Moazzam; Merkle, Johannes; Korte, Ulrike; Busch, Christoph
    The fuzzy vault is one of the most popular biometric encryption schemes for protecting fingerprint data. However, its implementation faces two challenges: First, the fingerprints need to be aligned. Some publications have proposed the storage of auxiliary data to assist alignment, but these data may leak information about the biometric features. Secondly, the fuzzy vault is susceptible to attacks that correlate the data from two protected templates, which does not only violate the requirement of unlinkability but also allows the recovery of the biometric data. In this work, we present a fuzzy vault construction for fingerprint data (minutiae) that addresses both issues. We do so by applying an absolute alignment method to the fingerprints, performing a quantization of the minutiae positions to a grid, and using all grid points unoccupied by minutiae as chaff. This approach results in all vaults containing the same set of points. In order to improve recognition performance, we also use the minutiae's angles and types. We present experimental evaluations and compare the results with the existing works on fuzzy fingerprint vault.
  • Konferenzbeitrag
    A cryptographic biometric authentication system based on genetic fingerprints
    (SICHERHEIT 2008 – Sicherheit, Schutz und Zuverlässigkeit. Beiträge der 4. Jahrestagung des Fachbereichs Sicherheit der Gesellschaft für Informatik e.V. (GI), 2008) Korte, Ulrike; Krawczak, Michael; Merkle, Johannes; Plaga, Rainer; Niesing, Matthias; Tiemann, Carsten; Vinck, Han; Martini, Ullrich
    We specify a system for authentication and key derivation using genetic fingerprints which prevents the recovery of biometric information from data stored for verification. We present a detailed security analysis based on estimates of the entropy of the DNA data and formal security results. The scheme is shown to be robust and efficient by analysing the typical frequency and structure of errors in DNA measurements and selecting appropriate error correcting codes. As a result we obtain an authentication system that offers a security level equivalent to cryptographic keys with 73 bits and a FRR well below 1%.
  • Konferenzbeitrag
    Efficient database techniques for identification with fuzzy vault templates
    (BIOSIG 2011 – Proceedings of the Biometrics Special Interest Group, 2011) Böhm, Christian; Färber, Ines; Fries, Sergej; Korte, Ulrike; Merkle, Johannes; Oswald, Annahita; Seidl, Thomas; Wackersreuther, Bianca; Wackersreuther, Peter
    The authentication based on biometric information has several advantages compared to solely password-based systems, which has led to a growing interest of industry and of public authorities in biometric-based systems. To meet the high security standards concerning biometric data, template protection systems such as the fuzzy vault are indispensable to maintain the secrecy of the critical information. Several publications have discussed the application of fuzzy vault to fingerprint authentication systems. However, for identification purposes in large databases the fuzzy vault protection of the biometric reference data poses severe efficiency challenges. In this work, we examine and compare the performance of three different approaches to enable the identification based on protected fingerprint minutiae templates also for large databases. All three approaches calculate a prioritization of the database entries exploiting filtering techniques and indexing structures. Based on this prioritization a search performing the complex exact comparison of database and query template is steered and thus will faster find a match.
  • Konferenzbeitrag
    Filtertechniken für geschützte biometrische Datenbanken
    (Datenbanksysteme für Business, Technologie und Web (BTW), 2011) Böhm, Christian; Färber, Ines; Fries, Sergej; Korte, Ulrike; Merkle, Johannes; Oswald, Annahita; Seidl, Thomas; Wackersreuther, Bianca; Wackersreuther, Peter
    In immer mehr sicherheitsrelevanten Bereichen werden biometrische Erkennungstechniken für die Zugangskontrolle oder die Identitätsfeststellung einer Person eingesetzt. Da biometrische Merkmale hoch sensibel sind, müssen sie vor unbefugtem Zugriff geschützt werden. Sogenannte Template Protection Verfahren ermöglichen eine biometrische Authentisierung, ohne dass sich diese Merkmale aus den gespeicherten Referenzdaten ermitteln lassen. Allerdings erschweren diese Verfahren die Suche nach passenden Referenzdaten und machen daher die Identifikation innerhalb umfangreicher Datenbestände ineffizient. In diesem Artikel werden erste Ansätze untersucht um auch für große Datenmengen eine Identifikation auf Basis von geschützten Fingerabdrücken durchführen zu können. Die vorgestellten Verfahren erstellen durch Filtertechniken und Indexstrukturen eine geeignete Priorisierung der Datenbankeinträge, sodass der aufwändige exakte Vergleich zwischen Anfrage und den transformierten Einträgen gezielt erfolgen kann.
  • Konferenzbeitrag
    Fingerprint Pre-Alignment based on Deep Learning
    (BIOSIG 2019 - Proceedings of the 18th International Conference of the Biometrics Special Interest Group, 2019) Dieckmann, Benjamin; Merkle, Johannes; Rathgeb, Christian
    Robust fingerprint pre-alignment is vital for identification systems and biometric cryptosystems based on fingerprint minutiae, where computation of a relative alignment by comparison of the fingerprints is inefficient or intractable, respectively. The pre-alignment is achieved through an absolute alignment, i. e. an alignment computed for each fingerprint independently, which can be applied for fingerprint registration to compensate for variations in the placement (translation) and rotation of the fingerprints prior to their comparison. In this work, a deep learning approach for absolute pre-alignment of fingerprints is presented. The proposed algorithm employs a siamese network (with CNNs as subnetworks) which is trained on synthetically generated fingerprints using horizontal/vertical translation and rotation as three regression coefficients. Evaluations are conducted on the FVC2000 DB2a and the MCYT fingerprint database. Compared to other published fingerprint pre-alignment methods, the presented scheme achieves higher accuracy w. r. t. rotation estimation and overall robustness. In addition, the proposed pre-alignment is applied as a pre-processing step in a Fuzzy Vault scheme.
  • Konferenzbeitrag
    Fusion of Face Demorphing and Deep Face Representations for Differential Morphing Attack Detection
    (BIOSIG 2022, 2022) Shiqerukaj, Elidona; Rathgeb, Christian; Merkle, Johannes; Drozdowski, Pawel; Tams, Benjamin
    Algorithm fusion is frequently employed to improve the accuracy of pattern recognition tasks. This particularly applies to biometrics including attack detection mechanisms. In this work, we apply a fusion of two differential morphing attack detection methods, i.e. Demorphing and Deep Face Representations. Experiments are performed in a cross-database scenario using high-quality face morphs along with realistic live captures. Obtained results reveal that a weighted sum-based score-level fusion of Demorphing and Deep Face Representations improves the morphing attack detection accuracy. With the proposed fusion, a detection equal error rate of 4.9% is achieved, compared to detection equal error rates of 5.6% and 5.8% of the best individual morphing attack detection methods, respectively.
  • Konferenzbeitrag
    Improved fuzzy vault scheme for alignment-free fingerprint features
    (BIOSIG 2015, 2015) Tams, Benjamin; Merkle, Johannes; Rathgeb, Christian; Wagner, Johannes; Korte, Ulrike; Busch, Christoph
    The fuzzy vault scheme is one of the most prominent tools for protecting fingerprint templates, typically being minutiae-based. However, there exist two major problems. Firstly, the fuzzy vault scheme is vulnerable to attacks correlating different templates of the same user. Secondly, auxiliary alignment data may leak information about the protected fingerprints which negatively affects security and privacy. In this paper, we tackle both problems. Our implementation uses alignment-free fingerprint features and fusions thereof, thereby removing the need to store alignment parameters. Furthermore, the features are passed through a quantization scheme and then dispersed in a maximal number of chaff, thereby thwarting correlation attacks.
  • Konferenzbeitrag
    Multi-modal and multi-instance fusion for biometric cryptosystems
    (BIOSIG 2012, 2012) Merkle, Johannes; Kevenaar, Tom; Korte, Ulrike
    Biometric cryptosystems allow cryptographic privacy protection for biometric reference data without storing a secret key. However, their security is inherently limited by the discriminative information content of the biometric feature data. Given the currently exploitable entropy of biometric features, one of the most promising approaches to achieve high privacy levels is to combine several biometric modalities or several instances of the same biometric modality. In this contribution, we theoretically analyze multibiometric fusion strategies for biometric cryptosystems with respect to their impact on security and recognition accuracy. We also introduce hash level as a new fusion level. Furthermore, we give a more detailed analysis for the most prominent schemes, the Fuzzy Commitment Scheme and the Fuzzy Vault.
  • Konferenzbeitrag
    Performance of the fuzzy vault for multiple fingerprints
    (BIOSIG 2010: Biometrics and Electronic Signatures. Proceedings of the Special Interest Group on Biometrics and Electronic Signatures, 2010) Merkle, Johannes; Niesing, Matthias; Schwaiger, Michael; Ihmor, Heinrich; Korte, Ulrike
    The fuzzy vault is an error tolerant authentication method that ensures the privacy of the stored reference data. Several publications have proposed the application of the fuzzy vault to fingerprints, but the results of subsequent analyses indicate that a single finger does not contain sufficient information for a secure implementation. In this contribution, we present an implementation of a fuzzy vault based on minutiae information in several fingerprints aiming at a security level comparable to current cryptographic applications. We analyze and empirically evaluate the security, efficiency, and robustness of the construction and several optimizations. The results allow an assessment of the capacity of the scheme and an appropriate selection of parameters.
  • Konferenzbeitrag
    A reference framework for the privacy assessment of keyless biometric template protection systems
    (BIOSIG 2010: Biometrics and Electronic Signatures. Proceedings of the Special Interest Group on Biometrics and Electronic Signatures, 2010) Kevenaar, Tom; Korte, Ulrike; Merkle, Johannes; Niesing, Matthias; Ihmor, Heinrich; Busch, Christoph; Zhou, Xuebing
    Over the past decades, a number of methods have been reported in the scientific literature to protect the privacy of biometric information stored in biometric systems. Keyless Biometric Template Protection (KBTP) methods aim to protect biometric information without the use of long-term secrets by deploying one-way functions. These KBTP methods are currently developed to an extent that commercial products have become available. When assessing and comparing different KBTP methods it is important to have a common and generic approach. Therefore, in this paper we present a reference framework that can be used in assessing and comparing the privacy properties of KBTP systems.