[{"year":"2017","title":"Attribute-Based Encryption as a Service for Access Control in Large-Scale Organizations","publisher":"Springer International Publishing","date_created":"2018-04-13T11:40:48Z","file":[{"content_type":"application/pdf","relation":"main_file","success":1,"date_created":"2018-11-02T15:04:13Z","creator":"ups","date_updated":"2018-11-02T15:04:13Z","access_level":"closed","file_id":"5292","file_name":"Attribute-BasedEncryptionAsASe.pdf","file_size":634736},{"relation":"main_file","content_type":"application/pdf","file_size":522516,"file_id":"5425","access_level":"open_access","file_name":"abe_aas.pdf","date_updated":"2018-11-08T09:53:34Z","creator":"nilo","date_created":"2018-11-08T09:53:34Z"}],"publication":"Foundations and Practice of Security","ddc":["000"],"language":[{"iso":"eng"}],"place":"Cham","page":"3-17","citation":{"apa":"Blömer, J., Günther, P., Krummel, V., &#38; Löken, N. (2017). Attribute-Based Encryption as a Service for Access Control in Large-Scale Organizations. In <i>Foundations and Practice of Security</i> (pp. 3–17). Cham: Springer International Publishing. <a href=\"https://doi.org/10.1007/978-3-319-75650-9_1\">https://doi.org/10.1007/978-3-319-75650-9_1</a>","short":"J. Blömer, P. Günther, V. Krummel, N. Löken, in: Foundations and Practice of Security, Springer International Publishing, Cham, 2017, pp. 3–17.","mla":"Blömer, Johannes, et al. “Attribute-Based Encryption as a Service for Access Control in Large-Scale Organizations.” <i>Foundations and Practice of Security</i>, Springer International Publishing, 2017, pp. 3–17, doi:<a href=\"https://doi.org/10.1007/978-3-319-75650-9_1\">10.1007/978-3-319-75650-9_1</a>.","bibtex":"@inproceedings{Blömer_Günther_Krummel_Löken_2017, place={Cham}, title={Attribute-Based Encryption as a Service for Access Control in Large-Scale Organizations}, DOI={<a href=\"https://doi.org/10.1007/978-3-319-75650-9_1\">10.1007/978-3-319-75650-9_1</a>}, booktitle={Foundations and Practice of Security}, publisher={Springer International Publishing}, author={Blömer, Johannes and Günther, Peter and Krummel, Volker and Löken, Nils}, year={2017}, pages={3–17} }","chicago":"Blömer, Johannes, Peter Günther, Volker Krummel, and Nils Löken. “Attribute-Based Encryption as a Service for Access Control in Large-Scale Organizations.” In <i>Foundations and Practice of Security</i>, 3–17. Cham: Springer International Publishing, 2017. <a href=\"https://doi.org/10.1007/978-3-319-75650-9_1\">https://doi.org/10.1007/978-3-319-75650-9_1</a>.","ieee":"J. Blömer, P. Günther, V. Krummel, and N. Löken, “Attribute-Based Encryption as a Service for Access Control in Large-Scale Organizations,” in <i>Foundations and Practice of Security</i>, 2017, pp. 3–17.","ama":"Blömer J, Günther P, Krummel V, Löken N. Attribute-Based Encryption as a Service for Access Control in Large-Scale Organizations. In: <i>Foundations and Practice of Security</i>. Cham: Springer International Publishing; 2017:3-17. doi:<a href=\"https://doi.org/10.1007/978-3-319-75650-9_1\">10.1007/978-3-319-75650-9_1</a>"},"has_accepted_license":"1","publication_identifier":{"issn":["0302-9743","1611-3349"],"isbn":["9783319756493","9783319756509"]},"publication_status":"published","doi":"10.1007/978-3-319-75650-9_1","date_updated":"2022-01-06T06:55:55Z","oa":"1","author":[{"id":"23","full_name":"Blömer, Johannes","last_name":"Blömer","first_name":"Johannes"},{"first_name":"Peter","last_name":"Günther","full_name":"Günther, Peter"},{"last_name":"Krummel","full_name":"Krummel, Volker","first_name":"Volker"},{"id":"13703","full_name":"Löken, Nils","last_name":"Löken","first_name":"Nils"}],"status":"public","type":"conference","file_date_updated":"2018-11-08T09:53:34Z","_id":"2344","project":[{"name":"SFB 901 - Subproject C1","_id":"13"},{"_id":"4","name":"SFB 901 - Project Area C"},{"_id":"1","name":"SFB 901"},{"name":"Securing the Financial Cloud","_id":"43"}],"department":[{"_id":"64"}],"user_id":"13703"},{"type":"conference","publication":"2015 Workshop on Fault Diagnosis and Tolerance in Cryptography (FDTC)","status":"public","user_id":"25078","department":[{"_id":"64"}],"project":[{"name":"Securing the Financial Cloud","_id":"43"}],"_id":"2947","publication_status":"published","publication_identifier":{"isbn":["9781467375795"]},"citation":{"apa":"Blömer, J., &#38; Günther, P. (2016). Singular Curve Point Decompression Attack. In <i>2015 Workshop on Fault Diagnosis and Tolerance in Cryptography (FDTC)</i>. IEEE. <a href=\"https://doi.org/10.1109/fdtc.2015.17\">https://doi.org/10.1109/fdtc.2015.17</a>","bibtex":"@inproceedings{Blömer_Günther_2016, title={Singular Curve Point Decompression Attack}, DOI={<a href=\"https://doi.org/10.1109/fdtc.2015.17\">10.1109/fdtc.2015.17</a>}, booktitle={2015 Workshop on Fault Diagnosis and Tolerance in Cryptography (FDTC)}, publisher={IEEE}, author={Blömer, Johannes and Günther, Peter}, year={2016} }","short":"J. Blömer, P. Günther, in: 2015 Workshop on Fault Diagnosis and Tolerance in Cryptography (FDTC), IEEE, 2016.","mla":"Blömer, Johannes, and Peter Günther. “Singular Curve Point Decompression Attack.” <i>2015 Workshop on Fault Diagnosis and Tolerance in Cryptography (FDTC)</i>, IEEE, 2016, doi:<a href=\"https://doi.org/10.1109/fdtc.2015.17\">10.1109/fdtc.2015.17</a>.","ama":"Blömer J, Günther P. Singular Curve Point Decompression Attack. In: <i>2015 Workshop on Fault Diagnosis and Tolerance in Cryptography (FDTC)</i>. IEEE; 2016. doi:<a href=\"https://doi.org/10.1109/fdtc.2015.17\">10.1109/fdtc.2015.17</a>","ieee":"J. Blömer and P. Günther, “Singular Curve Point Decompression Attack,” in <i>2015 Workshop on Fault Diagnosis and Tolerance in Cryptography (FDTC)</i>, 2016.","chicago":"Blömer, Johannes, and Peter Günther. “Singular Curve Point Decompression Attack.” In <i>2015 Workshop on Fault Diagnosis and Tolerance in Cryptography (FDTC)</i>. IEEE, 2016. <a href=\"https://doi.org/10.1109/fdtc.2015.17\">https://doi.org/10.1109/fdtc.2015.17</a>."},"year":"2016","date_created":"2018-05-29T11:25:43Z","author":[{"id":"23","full_name":"Blömer, Johannes","last_name":"Blömer","first_name":"Johannes"},{"first_name":"Peter","last_name":"Günther","full_name":"Günther, Peter"}],"publisher":"IEEE","date_updated":"2022-01-06T06:58:48Z","doi":"10.1109/fdtc.2015.17","title":"Singular Curve Point Decompression Attack"},{"_id":"2968","department":[{"_id":"64"}],"user_id":"25078","publication":"Algorithm Engineering","type":"book_chapter","status":"public","date_updated":"2022-01-06T06:58:49Z","publisher":"Springer International Publishing","author":[{"first_name":"Johannes","full_name":"Blömer, Johannes","id":"23","last_name":"Blömer"},{"full_name":"Lammersen, Christiane","last_name":"Lammersen","first_name":"Christiane"},{"first_name":"Melanie","full_name":"Schmidt, Melanie","last_name":"Schmidt"},{"full_name":"Sohler, Christian","last_name":"Sohler","first_name":"Christian"}],"date_created":"2018-06-04T12:22:40Z","title":"Theoretical Analysis of the k-Means Algorithm – A Survey","doi":"10.1007/978-3-319-49487-6_3","publication_identifier":{"isbn":["9783319494869","9783319494876"],"issn":["0302-9743","1611-3349"]},"publication_status":"published","place":"Cham","year":"2016","page":"81-116","citation":{"chicago":"Blömer, Johannes, Christiane Lammersen, Melanie Schmidt, and Christian Sohler. “Theoretical Analysis of the K-Means Algorithm – A Survey.” In <i>Algorithm Engineering</i>, 81–116. Cham: Springer International Publishing, 2016. <a href=\"https://doi.org/10.1007/978-3-319-49487-6_3\">https://doi.org/10.1007/978-3-319-49487-6_3</a>.","ieee":"J. Blömer, C. Lammersen, M. Schmidt, and C. Sohler, “Theoretical Analysis of the k-Means Algorithm – A Survey,” in <i>Algorithm Engineering</i>, Cham: Springer International Publishing, 2016, pp. 81–116.","ama":"Blömer J, Lammersen C, Schmidt M, Sohler C. Theoretical Analysis of the k-Means Algorithm – A Survey. In: <i>Algorithm Engineering</i>. Cham: Springer International Publishing; 2016:81-116. doi:<a href=\"https://doi.org/10.1007/978-3-319-49487-6_3\">10.1007/978-3-319-49487-6_3</a>","apa":"Blömer, J., Lammersen, C., Schmidt, M., &#38; Sohler, C. (2016). Theoretical Analysis of the k-Means Algorithm – A Survey. In <i>Algorithm Engineering</i> (pp. 81–116). Cham: Springer International Publishing. <a href=\"https://doi.org/10.1007/978-3-319-49487-6_3\">https://doi.org/10.1007/978-3-319-49487-6_3</a>","bibtex":"@inbook{Blömer_Lammersen_Schmidt_Sohler_2016, place={Cham}, title={Theoretical Analysis of the k-Means Algorithm – A Survey}, DOI={<a href=\"https://doi.org/10.1007/978-3-319-49487-6_3\">10.1007/978-3-319-49487-6_3</a>}, booktitle={Algorithm Engineering}, publisher={Springer International Publishing}, author={Blömer, Johannes and Lammersen, Christiane and Schmidt, Melanie and Sohler, Christian}, year={2016}, pages={81–116} }","short":"J. Blömer, C. Lammersen, M. Schmidt, C. Sohler, in: Algorithm Engineering, Springer International Publishing, Cham, 2016, pp. 81–116.","mla":"Blömer, Johannes, et al. “Theoretical Analysis of the K-Means Algorithm – A Survey.” <i>Algorithm Engineering</i>, Springer International Publishing, 2016, pp. 81–116, doi:<a href=\"https://doi.org/10.1007/978-3-319-49487-6_3\">10.1007/978-3-319-49487-6_3</a>."}},{"type":"preprint","status":"public","_id":"2969","user_id":"25078","department":[{"_id":"64"}],"year":"2016","citation":{"apa":"Blömer, J., Brauer, S., &#38; Bujna, K. (2016). Hard-Clustering with Gaussian Mixture Models. Computing Research Repository.","short":"J. Blömer, S. Brauer, K. Bujna, (2016).","bibtex":"@article{Blömer_Brauer_Bujna_2016, title={Hard-Clustering with Gaussian Mixture Models}, publisher={Computing Research Repository}, author={Blömer, Johannes and Brauer, Sascha and Bujna, Kathrin}, year={2016} }","mla":"Blömer, Johannes, et al. <i>Hard-Clustering with Gaussian Mixture Models</i>. Computing Research Repository, 2016.","ieee":"J. Blömer, S. Brauer, and K. Bujna, “Hard-Clustering with Gaussian Mixture Models.” Computing Research Repository, 2016.","chicago":"Blömer, Johannes, Sascha Brauer, and Kathrin Bujna. “Hard-Clustering with Gaussian Mixture Models.” Computing Research Repository, 2016.","ama":"Blömer J, Brauer S, Bujna K. Hard-Clustering with Gaussian Mixture Models. 2016."},"publisher":"Computing Research Repository","oa":"1","date_updated":"2022-01-06T06:58:49Z","author":[{"last_name":"Blömer","id":"23","full_name":"Blömer, Johannes","first_name":"Johannes"},{"last_name":"Brauer","id":"13291","full_name":"Brauer, Sascha","first_name":"Sascha"},{"last_name":"Bujna","full_name":"Bujna, Kathrin","first_name":"Kathrin"}],"date_created":"2018-06-04T12:26:51Z","title":"Hard-Clustering with Gaussian Mixture Models","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1603.06478"}]},{"title":"Adaptive Seeding for Gaussian Mixture Models","doi":"10.1007/978-3-319-31750-2_24","date_updated":"2022-01-06T06:58:49Z","publisher":"Springer International Publishing","author":[{"last_name":"Blömer","full_name":"Blömer, Johannes","id":"23","first_name":"Johannes"},{"first_name":"Kathrin","full_name":"Bujna, Kathrin","last_name":"Bujna"}],"date_created":"2018-06-04T12:27:21Z","year":"2016","place":"Cham","citation":{"apa":"Blömer, J., &#38; Bujna, K. (2016). Adaptive Seeding for Gaussian Mixture Models. In <i>Advances in Knowledge Discovery and Data Mining</i> (pp. 296–308). Cham: Springer International Publishing. <a href=\"https://doi.org/10.1007/978-3-319-31750-2_24\">https://doi.org/10.1007/978-3-319-31750-2_24</a>","bibtex":"@inbook{Blömer_Bujna_2016, place={Cham}, title={Adaptive Seeding for Gaussian Mixture Models}, DOI={<a href=\"https://doi.org/10.1007/978-3-319-31750-2_24\">10.1007/978-3-319-31750-2_24</a>}, booktitle={Advances in Knowledge Discovery and Data Mining}, publisher={Springer International Publishing}, author={Blömer, Johannes and Bujna, Kathrin}, year={2016}, pages={296–308} }","short":"J. Blömer, K. Bujna, in: Advances in Knowledge Discovery and Data Mining, Springer International Publishing, Cham, 2016, pp. 296–308.","mla":"Blömer, Johannes, and Kathrin Bujna. “Adaptive Seeding for Gaussian Mixture Models.” <i>Advances in Knowledge Discovery and Data Mining</i>, Springer International Publishing, 2016, pp. 296–308, doi:<a href=\"https://doi.org/10.1007/978-3-319-31750-2_24\">10.1007/978-3-319-31750-2_24</a>.","ama":"Blömer J, Bujna K. Adaptive Seeding for Gaussian Mixture Models. In: <i>Advances in Knowledge Discovery and Data Mining</i>. Cham: Springer International Publishing; 2016:296-308. doi:<a href=\"https://doi.org/10.1007/978-3-319-31750-2_24\">10.1007/978-3-319-31750-2_24</a>","ieee":"J. Blömer and K. Bujna, “Adaptive Seeding for Gaussian Mixture Models,” in <i>Advances in Knowledge Discovery and Data Mining</i>, Cham: Springer International Publishing, 2016, pp. 296–308.","chicago":"Blömer, Johannes, and Kathrin Bujna. “Adaptive Seeding for Gaussian Mixture Models.” In <i>Advances in Knowledge Discovery and Data Mining</i>, 296–308. Cham: Springer International Publishing, 2016. <a href=\"https://doi.org/10.1007/978-3-319-31750-2_24\">https://doi.org/10.1007/978-3-319-31750-2_24</a>."},"page":"296-308","publication_status":"published","publication_identifier":{"issn":["0302-9743","1611-3349"],"isbn":["9783319317496","9783319317502"]},"_id":"2970","user_id":"25078","department":[{"_id":"64"}],"status":"public","type":"book_chapter","publication":"Advances in Knowledge Discovery and Data Mining"},{"title":"Effizienz und Sicherheit paarungsbasierter Kryptographie","publisher":"Tagungsband des 26. Fraunhofer SIT Smartcard-Workshops","date_updated":"2022-01-06T06:58:49Z","author":[{"last_name":"Blömer","full_name":"Blömer, Johannes","id":"23","first_name":"Johannes"},{"first_name":"Peter","last_name":"Günther","full_name":"Günther, Peter"}],"date_created":"2018-06-05T07:21:25Z","year":"2016","citation":{"chicago":"Blömer, Johannes, and Peter Günther. <i>Effizienz Und Sicherheit Paarungsbasierter Kryptographie</i>. Tagungsband des 26. Fraunhofer SIT Smartcard-Workshops, 2016.","ieee":"J. Blömer and P. Günther, <i>Effizienz und Sicherheit paarungsbasierter Kryptographie</i>. Tagungsband des 26. Fraunhofer SIT Smartcard-Workshops, 2016.","ama":"Blömer J, Günther P. <i>Effizienz Und Sicherheit Paarungsbasierter Kryptographie</i>. Tagungsband des 26. Fraunhofer SIT Smartcard-Workshops; 2016.","short":"J. Blömer, P. Günther, Effizienz Und Sicherheit Paarungsbasierter Kryptographie, Tagungsband des 26. Fraunhofer SIT Smartcard-Workshops, 2016.","bibtex":"@book{Blömer_Günther_2016, title={Effizienz und Sicherheit paarungsbasierter Kryptographie}, publisher={Tagungsband des 26. Fraunhofer SIT Smartcard-Workshops}, author={Blömer, Johannes and Günther, Peter}, year={2016} }","mla":"Blömer, Johannes, and Peter Günther. <i>Effizienz Und Sicherheit Paarungsbasierter Kryptographie</i>. Tagungsband des 26. Fraunhofer SIT Smartcard-Workshops, 2016.","apa":"Blömer, J., &#38; Günther, P. (2016). <i>Effizienz und Sicherheit paarungsbasierter Kryptographie</i>. Tagungsband des 26. Fraunhofer SIT Smartcard-Workshops."},"publication_status":"published","_id":"2971","department":[{"_id":"64"}],"user_id":"25078","status":"public","type":"report"},{"keyword":["unsolvability by radicals","clustering","fuzzy k-means","probabilistic method","approximation algorithms","randomized algorithms"],"language":[{"iso":"eng"}],"_id":"2367","department":[{"_id":"64"}],"user_id":"25078","abstract":[{"text":"One of the most popular fuzzy clustering techniques is the fuzzy K-means algorithm (also known as fuzzy-c-means or FCM algorithm). In contrast to the K-means and K-median problem, the underlying fuzzy K-means problem has not been studied from a theoretical point of view. In particular, there are no algorithms with approximation guarantees similar to the famous K-means++ algorithm known for the fuzzy K-means problem. This work initiates the study of the fuzzy K-means problem from an algorithmic and complexity theoretic perspective. We show that optimal solutions for the fuzzy K-means problem cannot, in general, be expressed by radicals over the input points. Surprisingly, this already holds for simple inputs in one-dimensional space. Hence, one cannot expect to compute optimal solutions exactly. We give the first (1+eps)-approximation algorithms for the fuzzy K-means problem. First, we present a deterministic approximation algorithm whose runtime is polynomial in N and linear in the dimension D of the input set, given that K is constant, i.e. a polynomial time approximation scheme (PTAS) for fixed K. We achieve this result by showing that for each soft clustering there exists a hard clustering with similar properties. Second, by using techniques known from coreset constructions for the K-means problem, we develop a deterministic approximation algorithm that runs in time almost linear in N but exponential in the dimension D. We complement these results with a randomized algorithm which imposes some natural restrictions on the sought solution and whose runtime is comparable to some of the most efficient approximation algorithms for K-means, i.e. linear in the number of points and the dimension, but exponential in the number of clusters.","lang":"eng"}],"status":"public","publication":"2016 IEEE 16th International Conference on Data Mining (ICDM)","type":"conference","title":"A Theoretical Analysis of the Fuzzy K-Means Problem","conference":{"name":"IEEE 16th International Conference on Data Mining (ICDM)","start_date":"2016-12-12","end_date":"2016-12-15","location":"Barcelona, Spain"},"doi":"10.1109/icdm.2016.0094","publisher":"IEEE","date_updated":"2022-01-06T06:55:58Z","date_created":"2018-04-17T11:46:07Z","author":[{"first_name":"Johannes","last_name":"Blömer","id":"23","full_name":"Blömer, Johannes"},{"last_name":"Brauer","full_name":"Brauer, Sascha","id":"13291","first_name":"Sascha"},{"first_name":"Kathrin","full_name":"Bujna, Kathrin","last_name":"Bujna"}],"year":"2016","page":"805-810","citation":{"bibtex":"@inproceedings{Blömer_Brauer_Bujna_2016, title={A Theoretical Analysis of the Fuzzy K-Means Problem}, DOI={<a href=\"https://doi.org/10.1109/icdm.2016.0094\">10.1109/icdm.2016.0094</a>}, booktitle={2016 IEEE 16th International Conference on Data Mining (ICDM)}, publisher={IEEE}, author={Blömer, Johannes and Brauer, Sascha and Bujna, Kathrin}, year={2016}, pages={805–810} }","mla":"Blömer, Johannes, et al. “A Theoretical Analysis of the Fuzzy K-Means Problem.” <i>2016 IEEE 16th International Conference on Data Mining (ICDM)</i>, IEEE, 2016, pp. 805–10, doi:<a href=\"https://doi.org/10.1109/icdm.2016.0094\">10.1109/icdm.2016.0094</a>.","short":"J. Blömer, S. Brauer, K. Bujna, in: 2016 IEEE 16th International Conference on Data Mining (ICDM), IEEE, 2016, pp. 805–810.","apa":"Blömer, J., Brauer, S., &#38; Bujna, K. (2016). A Theoretical Analysis of the Fuzzy K-Means Problem. In <i>2016 IEEE 16th International Conference on Data Mining (ICDM)</i> (pp. 805–810). Barcelona, Spain: IEEE. <a href=\"https://doi.org/10.1109/icdm.2016.0094\">https://doi.org/10.1109/icdm.2016.0094</a>","ieee":"J. Blömer, S. Brauer, and K. Bujna, “A Theoretical Analysis of the Fuzzy K-Means Problem,” in <i>2016 IEEE 16th International Conference on Data Mining (ICDM)</i>, Barcelona, Spain, 2016, pp. 805–810.","chicago":"Blömer, Johannes, Sascha Brauer, and Kathrin Bujna. “A Theoretical Analysis of the Fuzzy K-Means Problem.” In <i>2016 IEEE 16th International Conference on Data Mining (ICDM)</i>, 805–10. IEEE, 2016. <a href=\"https://doi.org/10.1109/icdm.2016.0094\">https://doi.org/10.1109/icdm.2016.0094</a>.","ama":"Blömer J, Brauer S, Bujna K. A Theoretical Analysis of the Fuzzy K-Means Problem. In: <i>2016 IEEE 16th International Conference on Data Mining (ICDM)</i>. IEEE; 2016:805-810. doi:<a href=\"https://doi.org/10.1109/icdm.2016.0094\">10.1109/icdm.2016.0094</a>"},"publication_identifier":{"isbn":["9781509054732"]},"publication_status":"published"},{"author":[{"first_name":"Johannes","id":"23","full_name":"Blömer, Johannes","last_name":"Blömer"},{"first_name":"Gennadij","last_name":"Liske","full_name":"Liske, Gennadij"}],"date_created":"2017-10-17T12:41:32Z","date_updated":"2022-01-06T06:54:39Z","doi":"10.1007/978-3-319-29485-8_25","title":"Construction of Fully CCA-Secure Predicate Encryptions from Pair Encoding Schemes","has_accepted_license":"1","citation":{"ieee":"J. Blömer and G. Liske, “Construction of Fully CCA-Secure Predicate Encryptions from Pair Encoding Schemes,” in <i>Proceedings of the CT-RSA 2016</i>, 2016, pp. 431–447.","chicago":"Blömer, Johannes, and Gennadij Liske. “Construction of Fully CCA-Secure Predicate Encryptions from Pair Encoding Schemes.” In <i>Proceedings of the CT-RSA 2016</i>, 431–47. LNCS, 2016. <a href=\"https://doi.org/10.1007/978-3-319-29485-8_25\">https://doi.org/10.1007/978-3-319-29485-8_25</a>.","ama":"Blömer J, Liske G. Construction of Fully CCA-Secure Predicate Encryptions from Pair Encoding Schemes. In: <i>Proceedings of the CT-RSA 2016</i>. LNCS. ; 2016:431-447. doi:<a href=\"https://doi.org/10.1007/978-3-319-29485-8_25\">10.1007/978-3-319-29485-8_25</a>","mla":"Blömer, Johannes, and Gennadij Liske. “Construction of Fully CCA-Secure Predicate Encryptions from Pair Encoding Schemes.” <i>Proceedings of the CT-RSA 2016</i>, 2016, pp. 431–47, doi:<a href=\"https://doi.org/10.1007/978-3-319-29485-8_25\">10.1007/978-3-319-29485-8_25</a>.","short":"J. Blömer, G. Liske, in: Proceedings of the CT-RSA 2016, 2016, pp. 431–447.","bibtex":"@inproceedings{Blömer_Liske_2016, series={LNCS}, title={Construction of Fully CCA-Secure Predicate Encryptions from Pair Encoding Schemes}, DOI={<a href=\"https://doi.org/10.1007/978-3-319-29485-8_25\">10.1007/978-3-319-29485-8_25</a>}, booktitle={Proceedings of the CT-RSA 2016}, author={Blömer, Johannes and Liske, Gennadij}, year={2016}, pages={431–447}, collection={LNCS} }","apa":"Blömer, J., &#38; Liske, G. (2016). Construction of Fully CCA-Secure Predicate Encryptions from Pair Encoding Schemes. In <i>Proceedings of the CT-RSA 2016</i> (pp. 431–447). <a href=\"https://doi.org/10.1007/978-3-319-29485-8_25\">https://doi.org/10.1007/978-3-319-29485-8_25</a>"},"page":"431-447","year":"2016","series_title":"LNCS","user_id":"477","department":[{"_id":"64"}],"project":[{"_id":"1","name":"SFB 901"},{"_id":"13","name":"SFB 901 - Subprojekt C1"},{"name":"SFB 901 - Project Area C","_id":"4"}],"_id":"208","file_date_updated":"2018-03-21T10:43:36Z","ddc":["040"],"type":"conference","publication":"Proceedings of the CT-RSA 2016","file":[{"creator":"florida","date_created":"2018-03-21T10:43:36Z","date_updated":"2018-03-21T10:43:36Z","access_level":"closed","file_id":"1521","file_name":"208-aCCA_P-KEM_final.pdf","file_size":462666,"content_type":"application/pdf","relation":"main_file","success":1}],"status":"public","abstract":[{"text":"This paper presents a new framework for constructing fully CCA-secure predicate encryption schemes from pair encoding schemes. Our construction is the first in the context of predicate encryption which uses the technique of well-formedness proofs known from public key encryption. The resulting constructions are simpler and more efficient compared to the schemes achieved using known generic transformations from CPA-secure to CCA-secure schemes. The reduction costs of our framework are comparable to the reduction costs of the underlying CPA-secure framework. We achieve this last result by applying the dual system encryption methodology in a novel way.","lang":"eng"}]},{"date_created":"2018-06-05T07:31:39Z","author":[{"first_name":"Johannes","last_name":"Blömer","id":"23","full_name":"Blömer, Johannes"},{"first_name":"Kathrin","full_name":"Bujna, Kathrin","last_name":"Bujna"}],"publisher":"Springer International Publishing","date_updated":"2023-01-10T13:49:50Z","doi":"10.1007/978-3-319-31750-2_24","title":"Adaptive Seeding for Gaussian Mixture Models","publication_identifier":{"isbn":["9783319317496","9783319317502"],"issn":["0302-9743","1611-3349"]},"publication_status":"published","page":"296-308","citation":{"ama":"Blömer J, Bujna K. Adaptive Seeding for Gaussian Mixture Models. In: <i>Advances in Knowledge Discovery and Data Mining</i>. Springer International Publishing; 2016:296-308. doi:<a href=\"https://doi.org/10.1007/978-3-319-31750-2_24\">10.1007/978-3-319-31750-2_24</a>","chicago":"Blömer, Johannes, and Kathrin Bujna. “Adaptive Seeding for Gaussian Mixture Models.” In <i>Advances in Knowledge Discovery and Data Mining</i>, 296–308. Cham: Springer International Publishing, 2016. <a href=\"https://doi.org/10.1007/978-3-319-31750-2_24\">https://doi.org/10.1007/978-3-319-31750-2_24</a>.","ieee":"J. Blömer and K. Bujna, “Adaptive Seeding for Gaussian Mixture Models,” in <i>Advances in Knowledge Discovery and Data Mining</i>, Cham: Springer International Publishing, 2016, pp. 296–308.","apa":"Blömer, J., &#38; Bujna, K. (2016). Adaptive Seeding for Gaussian Mixture Models. In <i>Advances in Knowledge Discovery and Data Mining</i> (pp. 296–308). Springer International Publishing. <a href=\"https://doi.org/10.1007/978-3-319-31750-2_24\">https://doi.org/10.1007/978-3-319-31750-2_24</a>","bibtex":"@inbook{Blömer_Bujna_2016, place={Cham}, title={Adaptive Seeding for Gaussian Mixture Models}, DOI={<a href=\"https://doi.org/10.1007/978-3-319-31750-2_24\">10.1007/978-3-319-31750-2_24</a>}, booktitle={Advances in Knowledge Discovery and Data Mining}, publisher={Springer International Publishing}, author={Blömer, Johannes and Bujna, Kathrin}, year={2016}, pages={296–308} }","short":"J. Blömer, K. Bujna, in: Advances in Knowledge Discovery and Data Mining, Springer International Publishing, Cham, 2016, pp. 296–308.","mla":"Blömer, Johannes, and Kathrin Bujna. “Adaptive Seeding for Gaussian Mixture Models.” <i>Advances in Knowledge Discovery and Data Mining</i>, Springer International Publishing, 2016, pp. 296–308, doi:<a href=\"https://doi.org/10.1007/978-3-319-31750-2_24\">10.1007/978-3-319-31750-2_24</a>."},"year":"2016","place":"Cham","department":[{"_id":"64"}],"user_id":"25078","_id":"2978","publication":"Advances in Knowledge Discovery and Data Mining","type":"book_chapter","status":"public"},{"ddc":["000"],"language":[{"iso":"eng"}],"abstract":[{"lang":"eng","text":"Group signatures, introduced by Chaum and van Heyst [15], are an important primitive in cryptography. In group signature schemes every group member can anonymously sign messages on behalf of the group. In case of disputes a dedicated opening manager is able to trace signatures - he can extract the identity of the producer of a given signature. A formal model for static group signatures schemes and their security is defined by Bellare, Micciancio, and Warinschi [4], the case of dynamic groups is considered by Bellare, Shi, and Zhang [5]. Both models define group signature schemes with a single opening manager. The main difference between these models is that the number of group members in static schemes is fixed, while in dynamic schemes group members can join the group over time."}],"file":[{"date_created":"2018-11-02T14:08:23Z","creator":"ups","date_updated":"2018-11-02T14:08:23Z","file_id":"5262","file_name":"ShortGroupSignaturesWithDistri.pdf","access_level":"closed","file_size":262436,"content_type":"application/pdf","relation":"main_file","success":1}],"publication":"Proceedings of the Sixth International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)","title":"Short Group Signatures with Distributed Traceability","date_created":"2017-10-17T12:41:41Z","year":"2015","file_date_updated":"2018-11-02T14:08:23Z","project":[{"_id":"1","name":"SFB 901"},{"name":"SFB 901 - Subprojekt C1","_id":"13"},{"name":"SFB 901 - Project Area C","_id":"4"},{"name":"KogniHome - die mitdenkende Wohnung","_id":"44"}],"_id":"253","series_title":"LNCS","user_id":"13703","department":[{"_id":"64"}],"status":"public","type":"conference","doi":"10.1007/978-3-319-32859-1_14","date_updated":"2022-01-06T06:59:07Z","author":[{"first_name":"Johannes","full_name":"Blömer, Johannes","id":"23","last_name":"Blömer"},{"full_name":"Juhnke, Jakob","id":"48090","last_name":"Juhnke","first_name":"Jakob"},{"last_name":"Löken","full_name":"Löken, Nils","id":"13703","first_name":"Nils"}],"citation":{"ama":"Blömer J, Juhnke J, Löken N. Short Group Signatures with Distributed Traceability. In: <i>Proceedings of the Sixth International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)</i>. LNCS. ; 2015:166-180. doi:<a href=\"https://doi.org/10.1007/978-3-319-32859-1_14\">10.1007/978-3-319-32859-1_14</a>","chicago":"Blömer, Johannes, Jakob Juhnke, and Nils Löken. “Short Group Signatures with Distributed Traceability.” In <i>Proceedings of the Sixth International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)</i>, 166–80. LNCS, 2015. <a href=\"https://doi.org/10.1007/978-3-319-32859-1_14\">https://doi.org/10.1007/978-3-319-32859-1_14</a>.","ieee":"J. Blömer, J. Juhnke, and N. Löken, “Short Group Signatures with Distributed Traceability,” in <i>Proceedings of the Sixth International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)</i>, 2015, pp. 166–180.","apa":"Blömer, J., Juhnke, J., &#38; Löken, N. (2015). Short Group Signatures with Distributed Traceability. In <i>Proceedings of the Sixth International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)</i> (pp. 166–180). <a href=\"https://doi.org/10.1007/978-3-319-32859-1_14\">https://doi.org/10.1007/978-3-319-32859-1_14</a>","bibtex":"@inproceedings{Blömer_Juhnke_Löken_2015, series={LNCS}, title={Short Group Signatures with Distributed Traceability}, DOI={<a href=\"https://doi.org/10.1007/978-3-319-32859-1_14\">10.1007/978-3-319-32859-1_14</a>}, booktitle={Proceedings of the Sixth International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)}, author={Blömer, Johannes and Juhnke, Jakob and Löken, Nils}, year={2015}, pages={166–180}, collection={LNCS} }","mla":"Blömer, Johannes, et al. “Short Group Signatures with Distributed Traceability.” <i>Proceedings of the Sixth International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)</i>, 2015, pp. 166–80, doi:<a href=\"https://doi.org/10.1007/978-3-319-32859-1_14\">10.1007/978-3-319-32859-1_14</a>.","short":"J. Blömer, J. Juhnke, N. Löken, in: Proceedings of the Sixth International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS), 2015, pp. 166–180."},"page":"166-180","has_accepted_license":"1","related_material":{"record":[{"status":"public","id":"325","relation":"other"}]}},{"year":"2015","title":"Anonymous and Publicly Linkable Reputation Systems","date_created":"2017-10-17T12:41:54Z","abstract":[{"lang":"eng","text":"Reputation systems are used to compute and publish reputation scores for services or products. We consider reputation systems where users are allowed to rate products that they purchased previously. To obtain trustworthy reputations, they are allowed to rate these products only once. As long as users rate products once, they stay anonymous. Everybody is able to detect users deviating from the rate-products-only-once policy and the anonymity of such dishonest users can be revoked by a system manager. In this paper we present formal models for such reputation systems and their security. Based on group signatures presented by Boneh, Boyen, and Shacham we design an efficient reputation system that meets all our requirements."}],"file":[{"date_updated":"2018-03-20T07:39:54Z","creator":"florida","date_created":"2018-03-20T07:39:54Z","file_size":499568,"access_level":"closed","file_id":"1431","file_name":"322-546_01.pdf","content_type":"application/pdf","success":1,"relation":"main_file"}],"publication":"Proceedings of the 18th International Conference on Financial Cryptography and Data Security (FC)","ddc":["040"],"page":"478--488","citation":{"ieee":"J. Blömer, J. Juhnke, and C. Kolb, “Anonymous and Publicly Linkable Reputation Systems,” in <i>Proceedings of the 18th International Conference on Financial Cryptography and Data Security (FC)</i>, 2015, pp. 478--488.","chicago":"Blömer, Johannes, Jakob Juhnke, and Christina Kolb. “Anonymous and Publicly Linkable Reputation Systems.” In <i>Proceedings of the 18th International Conference on Financial Cryptography and Data Security (FC)</i>, 478--488. LNCS, 2015. <a href=\"https://doi.org/10.1007/978-3-662-47854-7_29\">https://doi.org/10.1007/978-3-662-47854-7_29</a>.","ama":"Blömer J, Juhnke J, Kolb C. Anonymous and Publicly Linkable Reputation Systems. In: <i>Proceedings of the 18th International Conference on Financial Cryptography and Data Security (FC)</i>. LNCS. ; 2015:478--488. doi:<a href=\"https://doi.org/10.1007/978-3-662-47854-7_29\">10.1007/978-3-662-47854-7_29</a>","short":"J. Blömer, J. Juhnke, C. Kolb, in: Proceedings of the 18th International Conference on Financial Cryptography and Data Security (FC), 2015, pp. 478--488.","bibtex":"@inproceedings{Blömer_Juhnke_Kolb_2015, series={LNCS}, title={Anonymous and Publicly Linkable Reputation Systems}, DOI={<a href=\"https://doi.org/10.1007/978-3-662-47854-7_29\">10.1007/978-3-662-47854-7_29</a>}, booktitle={Proceedings of the 18th International Conference on Financial Cryptography and Data Security (FC)}, author={Blömer, Johannes and Juhnke, Jakob and Kolb, Christina}, year={2015}, pages={478--488}, collection={LNCS} }","mla":"Blömer, Johannes, et al. “Anonymous and Publicly Linkable Reputation Systems.” <i>Proceedings of the 18th International Conference on Financial Cryptography and Data Security (FC)</i>, 2015, pp. 478--488, doi:<a href=\"https://doi.org/10.1007/978-3-662-47854-7_29\">10.1007/978-3-662-47854-7_29</a>.","apa":"Blömer, J., Juhnke, J., &#38; Kolb, C. (2015). Anonymous and Publicly Linkable Reputation Systems. In <i>Proceedings of the 18th International Conference on Financial Cryptography and Data Security (FC)</i> (pp. 478--488). <a href=\"https://doi.org/10.1007/978-3-662-47854-7_29\">https://doi.org/10.1007/978-3-662-47854-7_29</a>"},"has_accepted_license":"1","doi":"10.1007/978-3-662-47854-7_29","main_file_link":[{"open_access":"1","url":"https://eprint.iacr.org/2014/546"}],"date_updated":"2022-01-06T06:59:05Z","oa":"1","author":[{"first_name":"Johannes","id":"23","full_name":"Blömer, Johannes","last_name":"Blömer"},{"full_name":"Juhnke, Jakob","id":"48090","last_name":"Juhnke","first_name":"Jakob"},{"last_name":"Kolb","full_name":"Kolb, Christina","id":"43647","first_name":"Christina"}],"status":"public","type":"conference","file_date_updated":"2018-03-20T07:39:54Z","_id":"322","project":[{"_id":"1","name":"SFB 901"},{"name":"SFB 901 - Subprojekt C1","_id":"13"},{"_id":"4","name":"SFB 901 - Project Area C"}],"department":[{"_id":"64"}],"series_title":"LNCS","user_id":"48090"},{"has_accepted_license":"1","citation":{"bibtex":"@book{Blömer_Kohn_2015, title={Voronoi Cells of Lattices with Respect to Arbitrary Norms}, publisher={Universität Paderborn}, author={Blömer, Johannes and Kohn, Kathlén}, year={2015} }","mla":"Blömer, Johannes, and Kathlén Kohn. <i>Voronoi Cells of Lattices with Respect to Arbitrary Norms</i>. Universität Paderborn, 2015.","short":"J. Blömer, K. Kohn, Voronoi Cells of Lattices with Respect to Arbitrary Norms, Universität Paderborn, 2015.","apa":"Blömer, J., &#38; Kohn, K. (2015). <i>Voronoi Cells of Lattices with Respect to Arbitrary Norms</i>. Universität Paderborn.","ama":"Blömer J, Kohn K. <i>Voronoi Cells of Lattices with Respect to Arbitrary Norms</i>. Universität Paderborn; 2015.","ieee":"J. Blömer and K. Kohn, <i>Voronoi Cells of Lattices with Respect to Arbitrary Norms</i>. Universität Paderborn, 2015.","chicago":"Blömer, Johannes, and Kathlén Kohn. <i>Voronoi Cells of Lattices with Respect to Arbitrary Norms</i>. Universität Paderborn, 2015."},"year":"2015","date_created":"2017-10-17T12:41:37Z","author":[{"first_name":"Johannes","last_name":"Blömer","id":"23","full_name":"Blömer, Johannes"},{"full_name":"Kohn, Kathlén","last_name":"Kohn","first_name":"Kathlén"}],"oa":"1","publisher":"Universität Paderborn","date_updated":"2022-01-06T06:55:49Z","main_file_link":[{"open_access":"1","url":"http://arxiv.org/pdf/1512.00720v1.pdf"}],"title":"Voronoi Cells of Lattices with Respect to Arbitrary Norms","type":"report","file":[{"content_type":"application/pdf","relation":"main_file","success":1,"creator":"florida","date_created":"2018-03-21T10:30:18Z","date_updated":"2018-03-21T10:30:18Z","access_level":"closed","file_id":"1501","file_name":"233-1512.00720v1.pdf","file_size":1231102}],"status":"public","abstract":[{"lang":"eng","text":"Motivated by the deterministic single exponential time algorithm of Micciancio and Voulgaris for solving the shortest and closest vector problem for the Euclidean norm, we study the geometry and complexity of Voronoi cells of lattices with respect to arbitrary norms.On the positive side, we show that for strictly convex and smooth norms the geometry of Voronoi cells of lattices in any dimension is similar to the Euclidean case, i.e., the Voronoi cells are defined by the so-called Voronoi-relevant vectors and the facets of a Voronoi cell are in one-to-one correspondence with these vectors. On the negative side, we show that combinatorially Voronoi cells for arbitrary strictly convex and smooth norms are much more complicated than in the Euclidean case.In particular, we construct a family of three-dimensional lattices whose number of Voronoi-relevant vectors with respect to the l_3-norm is unbounded.Since the algorithm of Micciancio and Voulgaris and its run time analysis crucially dependonthefactthatfortheEuclidean normthenumber of Voronoi-relevant vectors is single exponential in the lattice dimension, this indicates that the techniques of Micciancio and Voulgaris cannot be extended to achieve deterministic single exponential time algorithms for lattice problems with respect to arbitrary l_p-norms."}],"user_id":"25078","department":[{"_id":"64"}],"project":[{"name":"SFB 901","_id":"1"},{"name":"SFB 901 - Subprojekt C1","_id":"13"},{"_id":"4","name":"SFB 901 - Project Area C"}],"_id":"233","file_date_updated":"2018-03-21T10:30:18Z","ddc":["040"]},{"title":"Tampering attacks in pairing-based cryptography","doi":"10.1109/FDTC.2014.10","date_updated":"2022-01-06T06:59:23Z","author":[{"first_name":"Johannes","id":"23","full_name":"Blömer, Johannes","last_name":"Blömer"},{"first_name":"Peter","last_name":"Günther","full_name":"Günther, Peter"},{"first_name":"Gennadij","last_name":"Liske","full_name":"Liske, Gennadij"}],"date_created":"2017-10-17T12:42:01Z","year":"2014","citation":{"ieee":"J. Blömer, P. Günther, and G. Liske, “Tampering attacks in pairing-based cryptography,” in <i>Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)</i>, 2014, pp. 1--7.","chicago":"Blömer, Johannes, Peter Günther, and Gennadij Liske. “Tampering Attacks in Pairing-Based Cryptography.” In <i>Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)</i>, 1--7, 2014. <a href=\"https://doi.org/10.1109/FDTC.2014.10\">https://doi.org/10.1109/FDTC.2014.10</a>.","ama":"Blömer J, Günther P, Liske G. Tampering attacks in pairing-based cryptography. In: <i>Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)</i>. ; 2014:1--7. doi:<a href=\"https://doi.org/10.1109/FDTC.2014.10\">10.1109/FDTC.2014.10</a>","bibtex":"@inproceedings{Blömer_Günther_Liske_2014, title={Tampering attacks in pairing-based cryptography}, DOI={<a href=\"https://doi.org/10.1109/FDTC.2014.10\">10.1109/FDTC.2014.10</a>}, booktitle={Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)}, author={Blömer, Johannes and Günther, Peter and Liske, Gennadij}, year={2014}, pages={1--7} }","mla":"Blömer, Johannes, et al. “Tampering Attacks in Pairing-Based Cryptography.” <i>Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)</i>, 2014, pp. 1--7, doi:<a href=\"https://doi.org/10.1109/FDTC.2014.10\">10.1109/FDTC.2014.10</a>.","short":"J. Blömer, P. Günther, G. Liske, in: Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC), 2014, pp. 1--7.","apa":"Blömer, J., Günther, P., &#38; Liske, G. (2014). Tampering attacks in pairing-based cryptography. In <i>Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)</i> (pp. 1--7). <a href=\"https://doi.org/10.1109/FDTC.2014.10\">https://doi.org/10.1109/FDTC.2014.10</a>"},"page":"1--7","has_accepted_license":"1","ddc":["040"],"file_date_updated":"2018-03-20T07:22:29Z","project":[{"_id":"1","name":"SFB 901"},{"_id":"13","name":"SFB 901 - Subprojekt C1"},{"name":"SFB 901 - Project Area C","_id":"4"},{"_id":"43","name":"Securing the Financial Cloud"}],"_id":"355","user_id":"25078","department":[{"_id":"64"}],"abstract":[{"lang":"eng","text":"In the last decade pairings have become an important, and often indispensable, ingredient in the construction of identity-based and attribute-based cryptosystems, as well as group signatures and credential systems. Consequently, the applicability of timing, power, or fault attacks to implementations of pairings is an important research topic. We will review some of the known results in this area."}],"file":[{"content_type":"application/pdf","relation":"main_file","success":1,"date_created":"2018-03-20T07:22:29Z","creator":"florida","date_updated":"2018-03-20T07:22:29Z","file_id":"1412","access_level":"closed","file_name":"355-Bloemer2014.pdf","file_size":293394}],"status":"public","type":"conference","publication":"Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)"},{"title":"Analysis of Agglomerative Clustering","doi":"10.1007/s00453-012-9717-4","date_updated":"2022-01-06T06:58:49Z","publisher":"Springer US","volume":69,"author":[{"last_name":"Ackermann","full_name":"Ackermann, Marcel Rudolf","first_name":"Marcel Rudolf"},{"first_name":"Johannes","full_name":"Blömer, Johannes","id":"23","last_name":"Blömer"},{"full_name":"Kuntze, Daniel","last_name":"Kuntze","first_name":"Daniel"},{"first_name":"Christian","last_name":"Sohler","full_name":"Sohler, Christian"}],"date_created":"2018-06-05T07:28:52Z","year":"2014","intvolume":"        69","citation":{"bibtex":"@article{Ackermann_Blömer_Kuntze_Sohler_2014, title={Analysis of Agglomerative Clustering}, volume={69}, DOI={<a href=\"https://doi.org/10.1007/s00453-012-9717-4\">10.1007/s00453-012-9717-4</a>}, journal={Algorithmica}, publisher={Springer US}, author={Ackermann, Marcel Rudolf and Blömer, Johannes and Kuntze, Daniel and Sohler, Christian}, year={2014} }","mla":"Ackermann, Marcel Rudolf, et al. “Analysis of Agglomerative Clustering.” <i>Algorithmica</i>, vol. 69, Springer US, 2014, doi:<a href=\"https://doi.org/10.1007/s00453-012-9717-4\">10.1007/s00453-012-9717-4</a>.","short":"M.R. Ackermann, J. Blömer, D. Kuntze, C. Sohler, Algorithmica 69 (2014).","apa":"Ackermann, M. R., Blömer, J., Kuntze, D., &#38; Sohler, C. (2014). Analysis of Agglomerative Clustering. <i>Algorithmica</i>, <i>69</i>. <a href=\"https://doi.org/10.1007/s00453-012-9717-4\">https://doi.org/10.1007/s00453-012-9717-4</a>","ama":"Ackermann MR, Blömer J, Kuntze D, Sohler C. Analysis of Agglomerative Clustering. <i>Algorithmica</i>. 2014;69. doi:<a href=\"https://doi.org/10.1007/s00453-012-9717-4\">10.1007/s00453-012-9717-4</a>","ieee":"M. R. Ackermann, J. Blömer, D. Kuntze, and C. Sohler, “Analysis of Agglomerative Clustering,” <i>Algorithmica</i>, vol. 69, 2014.","chicago":"Ackermann, Marcel Rudolf, Johannes Blömer, Daniel Kuntze, and Christian Sohler. “Analysis of Agglomerative Clustering.” <i>Algorithmica</i> 69 (2014). <a href=\"https://doi.org/10.1007/s00453-012-9717-4\">https://doi.org/10.1007/s00453-012-9717-4</a>."},"publication_identifier":{"eissn":["0178-4617"]},"publication_status":"published","_id":"2976","department":[{"_id":"64"}],"user_id":"25078","status":"public","publication":"Algorithmica","type":"journal_article"},{"year":"2014","citation":{"ieee":"J. Blömer, K. Bujna, and D. Kuntze, “A Theoretical and Experimental Comparison of the EM and SEM Algorithm,” in <i>2014 22nd International Conference on Pattern Recognition</i>, 2014.","chicago":"Blömer, Johannes, Kathrin Bujna, and Daniel Kuntze. “A Theoretical and Experimental Comparison of the EM and SEM Algorithm.” In <i>2014 22nd International Conference on Pattern Recognition</i>. IEEE, 2014. <a href=\"https://doi.org/10.1109/icpr.2014.253\">https://doi.org/10.1109/icpr.2014.253</a>.","ama":"Blömer J, Bujna K, Kuntze D. A Theoretical and Experimental Comparison of the EM and SEM Algorithm. In: <i>2014 22nd International Conference on Pattern Recognition</i>. IEEE; 2014. doi:<a href=\"https://doi.org/10.1109/icpr.2014.253\">10.1109/icpr.2014.253</a>","apa":"Blömer, J., Bujna, K., &#38; Kuntze, D. (2014). A Theoretical and Experimental Comparison of the EM and SEM Algorithm. In <i>2014 22nd International Conference on Pattern Recognition</i>. IEEE. <a href=\"https://doi.org/10.1109/icpr.2014.253\">https://doi.org/10.1109/icpr.2014.253</a>","mla":"Blömer, Johannes, et al. “A Theoretical and Experimental Comparison of the EM and SEM Algorithm.” <i>2014 22nd International Conference on Pattern Recognition</i>, IEEE, 2014, doi:<a href=\"https://doi.org/10.1109/icpr.2014.253\">10.1109/icpr.2014.253</a>.","short":"J. Blömer, K. Bujna, D. Kuntze, in: 2014 22nd International Conference on Pattern Recognition, IEEE, 2014.","bibtex":"@inproceedings{Blömer_Bujna_Kuntze_2014, title={A Theoretical and Experimental Comparison of the EM and SEM Algorithm}, DOI={<a href=\"https://doi.org/10.1109/icpr.2014.253\">10.1109/icpr.2014.253</a>}, booktitle={2014 22nd International Conference on Pattern Recognition}, publisher={IEEE}, author={Blömer, Johannes and Bujna, Kathrin and Kuntze, Daniel}, year={2014} }"},"publication_status":"published","publication_identifier":{"isbn":["9781479952090"]},"title":"A Theoretical and Experimental Comparison of the EM and SEM Algorithm","doi":"10.1109/icpr.2014.253","date_updated":"2022-01-06T06:58:49Z","publisher":"IEEE","date_created":"2018-06-05T07:29:15Z","author":[{"id":"23","full_name":"Blömer, Johannes","last_name":"Blömer","first_name":"Johannes"},{"full_name":"Bujna, Kathrin","last_name":"Bujna","first_name":"Kathrin"},{"full_name":"Kuntze, Daniel","last_name":"Kuntze","first_name":"Daniel"}],"status":"public","type":"conference","publication":"2014 22nd International Conference on Pattern Recognition","_id":"2977","user_id":"25078","department":[{"_id":"64"}]},{"publisher":"Universität Paderborn","oa":"1","date_updated":"2022-01-06T07:01:03Z","author":[{"last_name":"Blömer","full_name":"Blömer, Johannes","id":"23","first_name":"Johannes"},{"first_name":"Gennadij","last_name":"Liske","full_name":"Liske, Gennadij"}],"date_created":"2017-10-17T12:42:18Z","title":"Constructing CCA-secure predicate encapsulation schemes from CPA-secure schemes and universal one-way hash functions","main_file_link":[{"url":"https://eprint.iacr.org/2014/511.pdf","open_access":"1"}],"has_accepted_license":"1","year":"2014","citation":{"short":"J. Blömer, G. Liske, (2014).","mla":"Blömer, Johannes, and Gennadij Liske. <i>Constructing CCA-Secure Predicate Encapsulation Schemes from CPA-Secure Schemes and Universal One-Way Hash Functions</i>. Universität Paderborn, 2014.","bibtex":"@article{Blömer_Liske_2014, title={Constructing CCA-secure predicate encapsulation schemes from CPA-secure schemes and universal one-way hash functions}, publisher={Universität Paderborn}, author={Blömer, Johannes and Liske, Gennadij}, year={2014} }","apa":"Blömer, J., &#38; Liske, G. (2014). Constructing CCA-secure predicate encapsulation schemes from CPA-secure schemes and universal one-way hash functions. Universität Paderborn.","chicago":"Blömer, Johannes, and Gennadij Liske. “Constructing CCA-Secure Predicate Encapsulation Schemes from CPA-Secure Schemes and Universal One-Way Hash Functions.” Universität Paderborn, 2014.","ieee":"J. Blömer and G. Liske, “Constructing CCA-secure predicate encapsulation schemes from CPA-secure schemes and universal one-way hash functions.” Universität Paderborn, 2014.","ama":"Blömer J, Liske G. Constructing CCA-secure predicate encapsulation schemes from CPA-secure schemes and universal one-way hash functions. 2014."},"_id":"442","project":[{"_id":"1","name":"SFB 901"},{"name":"SFB 901 - Subprojekt C1","_id":"13"},{"name":"SFB 901 - Project Area C","_id":"4"},{"_id":"43","name":"Securing the Financial Cloud"}],"department":[{"_id":"64"}],"user_id":"25078","ddc":["000"],"file_date_updated":"2018-03-16T11:28:34Z","type":"preprint","abstract":[{"text":"We present a new transformation of chosen-plaintext secure predicate encryption schemes with public index into chosen-ciphertext secure schemes. Our construction requires only a universal one-way hash function and is selectively secure in the standard model. The transformation is not generic but can be applied to various existing schemes constructed from bilinear groups. Using common structural properties of these schemes we provide an efficient and simple transformation without overhead in form of one-time signatures or message authentication codes as required in the known generic transformations.","lang":"eng"}],"status":"public","file":[{"access_level":"closed","file_id":"1351","file_name":"442-P-KEM.pdf","file_size":377945,"creator":"florida","date_created":"2018-03-16T11:28:34Z","date_updated":"2018-03-16T11:28:34Z","relation":"main_file","success":1,"content_type":"application/pdf"}]},{"date_updated":"2022-01-06T07:01:16Z","date_created":"2017-10-17T12:42:22Z","author":[{"full_name":"Blömer, Johannes","id":"23","last_name":"Blömer","first_name":"Johannes"},{"first_name":"Ricardo","full_name":"Gomes da Silva, Ricardo","last_name":"Gomes da Silva"},{"first_name":"Peter","last_name":"Günther","full_name":"Günther, Peter"},{"full_name":"Krämer, Juliane","last_name":"Krämer","first_name":"Juliane"},{"first_name":"Jean-Pierre","last_name":"Seifert","full_name":"Seifert, Jean-Pierre"}],"title":"A Practical Second-Order Fault Attack against a Real-World Pairing Implementation","doi":"10.1109/FDTC.2014.22","has_accepted_license":"1","year":"2014","page":"123--136","citation":{"ama":"Blömer J, Gomes da Silva R, Günther P, Krämer J, Seifert J-P. A Practical Second-Order Fault Attack against a Real-World Pairing Implementation. In: <i>Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)</i>. ; 2014:123--136. doi:<a href=\"https://doi.org/10.1109/FDTC.2014.22\">10.1109/FDTC.2014.22</a>","chicago":"Blömer, Johannes, Ricardo Gomes da Silva, Peter Günther, Juliane Krämer, and Jean-Pierre Seifert. “A Practical Second-Order Fault Attack against a Real-World Pairing Implementation.” In <i>Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)</i>, 123--136, 2014. <a href=\"https://doi.org/10.1109/FDTC.2014.22\">https://doi.org/10.1109/FDTC.2014.22</a>.","ieee":"J. Blömer, R. Gomes da Silva, P. Günther, J. Krämer, and J.-P. Seifert, “A Practical Second-Order Fault Attack against a Real-World Pairing Implementation,” in <i>Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)</i>, 2014, pp. 123--136.","apa":"Blömer, J., Gomes da Silva, R., Günther, P., Krämer, J., &#38; Seifert, J.-P. (2014). A Practical Second-Order Fault Attack against a Real-World Pairing Implementation. In <i>Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)</i> (pp. 123--136). <a href=\"https://doi.org/10.1109/FDTC.2014.22\">https://doi.org/10.1109/FDTC.2014.22</a>","bibtex":"@inproceedings{Blömer_Gomes da Silva_Günther_Krämer_Seifert_2014, title={A Practical Second-Order Fault Attack against a Real-World Pairing Implementation}, DOI={<a href=\"https://doi.org/10.1109/FDTC.2014.22\">10.1109/FDTC.2014.22</a>}, booktitle={Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)}, author={Blömer, Johannes and Gomes da Silva, Ricardo and Günther, Peter and Krämer, Juliane and Seifert, Jean-Pierre}, year={2014}, pages={123--136} }","mla":"Blömer, Johannes, et al. “A Practical Second-Order Fault Attack against a Real-World Pairing Implementation.” <i>Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)</i>, 2014, pp. 123--136, doi:<a href=\"https://doi.org/10.1109/FDTC.2014.22\">10.1109/FDTC.2014.22</a>.","short":"J. Blömer, R. Gomes da Silva, P. Günther, J. Krämer, J.-P. Seifert, in: Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC), 2014, pp. 123--136."},"_id":"463","project":[{"_id":"1","name":"SFB 901"},{"name":"SFB 901 - Subprojekt C1","_id":"13"},{"_id":"4","name":"SFB 901 - Project Area C"},{"_id":"43","name":"Securing the Financial Cloud"}],"department":[{"_id":"64"}],"user_id":"25078","ddc":["040"],"file_date_updated":"2018-03-16T11:20:54Z","publication":"Proceedings of Fault Tolerance and Diagnosis in Cryptography(FDTC)","type":"conference","abstract":[{"text":"Several fault attacks against pairing-based cryptography have been described theoretically in recent years. Interestingly, none of these have been practically evaluated. We accomplished this task and prove that fault attacks against pairing-based cryptography are indeed possible and are even practical — thus posing a serious threat. Moreover, we successfully conducted a second-order fault attack against an open source implementation of the eta pairing on an AVR XMEGA A1. We injected the first fault into the computation of the Miller Algorithm and applied the second fault to skip the final exponentiation completely. We introduce a low-cost setup that allowed us to generate multiple independent faults in one computation. The setup implements these faults by clock glitches which induce instruction skips. With this setup we conducted the first practical fault attack against a complete pairing computation.","lang":"eng"}],"status":"public","file":[{"content_type":"application/pdf","success":1,"relation":"main_file","date_updated":"2018-03-16T11:20:54Z","creator":"florida","date_created":"2018-03-16T11:20:54Z","file_size":437518,"file_name":"463-FDTC14.pdf","file_id":"1336","access_level":"closed"}]},{"department":[{"_id":"64"}],"user_id":"25078","_id":"2979","publication":"Constructive Side-Channel Analysis and Secure Design","type":"book_chapter","status":"public","date_created":"2018-06-05T07:33:22Z","author":[{"full_name":"Blömer, Johannes","id":"23","last_name":"Blömer","first_name":"Johannes"},{"first_name":"Peter","last_name":"Günther","full_name":"Günther, Peter"},{"full_name":"Liske, Gennadij","last_name":"Liske","first_name":"Gennadij"}],"date_updated":"2022-01-06T06:58:49Z","publisher":"Springer Berlin Heidelberg","doi":"10.1007/978-3-642-40026-1_10","title":"Improved Side Channel Attacks on Pairing Based Cryptography","publication_identifier":{"issn":["0302-9743","1611-3349"],"isbn":["9783642400254","9783642400261"]},"publication_status":"published","page":"154-168","citation":{"ama":"Blömer J, Günther P, Liske G. Improved Side Channel Attacks on Pairing Based Cryptography. In: <i>Constructive Side-Channel Analysis and Secure Design</i>. Berlin, Heidelberg: Springer Berlin Heidelberg; 2013:154-168. doi:<a href=\"https://doi.org/10.1007/978-3-642-40026-1_10\">10.1007/978-3-642-40026-1_10</a>","ieee":"J. Blömer, P. Günther, and G. Liske, “Improved Side Channel Attacks on Pairing Based Cryptography,” in <i>Constructive Side-Channel Analysis and Secure Design</i>, Berlin, Heidelberg: Springer Berlin Heidelberg, 2013, pp. 154–168.","chicago":"Blömer, Johannes, Peter Günther, and Gennadij Liske. “Improved Side Channel Attacks on Pairing Based Cryptography.” In <i>Constructive Side-Channel Analysis and Secure Design</i>, 154–68. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. <a href=\"https://doi.org/10.1007/978-3-642-40026-1_10\">https://doi.org/10.1007/978-3-642-40026-1_10</a>.","apa":"Blömer, J., Günther, P., &#38; Liske, G. (2013). Improved Side Channel Attacks on Pairing Based Cryptography. In <i>Constructive Side-Channel Analysis and Secure Design</i> (pp. 154–168). Berlin, Heidelberg: Springer Berlin Heidelberg. <a href=\"https://doi.org/10.1007/978-3-642-40026-1_10\">https://doi.org/10.1007/978-3-642-40026-1_10</a>","bibtex":"@inbook{Blömer_Günther_Liske_2013, place={Berlin, Heidelberg}, title={Improved Side Channel Attacks on Pairing Based Cryptography}, DOI={<a href=\"https://doi.org/10.1007/978-3-642-40026-1_10\">10.1007/978-3-642-40026-1_10</a>}, booktitle={Constructive Side-Channel Analysis and Secure Design}, publisher={Springer Berlin Heidelberg}, author={Blömer, Johannes and Günther, Peter and Liske, Gennadij}, year={2013}, pages={154–168} }","mla":"Blömer, Johannes, et al. “Improved Side Channel Attacks on Pairing Based Cryptography.” <i>Constructive Side-Channel Analysis and Secure Design</i>, Springer Berlin Heidelberg, 2013, pp. 154–68, doi:<a href=\"https://doi.org/10.1007/978-3-642-40026-1_10\">10.1007/978-3-642-40026-1_10</a>.","short":"J. Blömer, P. Günther, G. Liske, in: Constructive Side-Channel Analysis and Secure Design, Springer Berlin Heidelberg, Berlin, Heidelberg, 2013, pp. 154–168."},"place":"Berlin, Heidelberg","year":"2013"},{"file_date_updated":"2018-03-15T13:46:52Z","ddc":["040"],"department":[{"_id":"64"}],"user_id":"477","_id":"488","project":[{"_id":"1","name":"SFB 901"},{"name":"SFB 901 - Subprojekt C1","_id":"13"},{"_id":"4","name":"SFB 901 - Project Area C"}],"status":"public","file":[{"date_updated":"2018-03-15T13:46:52Z","creator":"florida","date_created":"2018-03-15T13:46:52Z","file_size":301962,"access_level":"closed","file_id":"1317","file_name":"488-MACIS13.pdf","content_type":"application/pdf","success":1,"relation":"main_file"}],"abstract":[{"text":"Unattended systems are key ingredients of various critical infrastruc-tures like networks of self service terminals or automated teller machines.For cost and efficiency reasons they should mostly run autonomously.Unattended systems are attractive and lucrative targets for various kindsof attacks, including attacks on the integrity of their components and thecommunication between components. In this paper, we propose a gen-eral cryptographic framework to protect unattended systems. We alsodemonstrate that instantiating the framework with techniques from iden-tity based cryptography is particularly well-suited to efficiently secureunattended systems.","lang":"eng"}],"publication":"Proceedings of the 5th International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)","type":"conference","title":"Securing Critical Unattended Systems with Identity Based Cryptography - A Case Study","date_created":"2017-10-17T12:42:27Z","author":[{"last_name":"Blömer","full_name":"Blömer, Johannes","id":"23","first_name":"Johannes"},{"first_name":"Peter","full_name":"Günther, Peter","last_name":"Günther"},{"full_name":"Krummel, Volker","last_name":"Krummel","first_name":"Volker"}],"date_updated":"2022-01-06T07:01:28Z","page":"98-105","citation":{"ieee":"J. Blömer, P. Günther, and V. Krummel, “Securing Critical Unattended Systems with Identity Based Cryptography - A Case Study,” in <i>Proceedings of the 5th International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)</i>, 2013, pp. 98–105.","chicago":"Blömer, Johannes, Peter Günther, and Volker Krummel. “Securing Critical Unattended Systems with Identity Based Cryptography - A Case Study.” In <i>Proceedings of the 5th International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)</i>, 98–105, 2013.","ama":"Blömer J, Günther P, Krummel V. Securing Critical Unattended Systems with Identity Based Cryptography - A Case Study. In: <i>Proceedings of the 5th International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)</i>. ; 2013:98-105.","mla":"Blömer, Johannes, et al. “Securing Critical Unattended Systems with Identity Based Cryptography - A Case Study.” <i>Proceedings of the 5th International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)</i>, 2013, pp. 98–105.","bibtex":"@inproceedings{Blömer_Günther_Krummel_2013, title={Securing Critical Unattended Systems with Identity Based Cryptography - A Case Study}, booktitle={Proceedings of the 5th International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)}, author={Blömer, Johannes and Günther, Peter and Krummel, Volker}, year={2013}, pages={98–105} }","short":"J. Blömer, P. Günther, V. Krummel, in: Proceedings of the 5th International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS), 2013, pp. 98–105.","apa":"Blömer, J., Günther, P., &#38; Krummel, V. (2013). Securing Critical Unattended Systems with Identity Based Cryptography - A Case Study. In <i>Proceedings of the 5th International Conference on Mathematical Aspects of Computer and Information Sciences (MACIS)</i> (pp. 98–105)."},"year":"2013","has_accepted_license":"1"},{"title":"Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles","main_file_link":[{"open_access":"1","url":"https://eprint.iacr.org/2013/646"}],"publisher":"Universität Paderborn","date_updated":"2022-01-06T07:01:51Z","oa":"1","author":[{"last_name":"Blömer","id":"23","full_name":"Blömer, Johannes","first_name":"Johannes"},{"full_name":"Liske, Gennadij","last_name":"Liske","first_name":"Gennadij"}],"date_created":"2017-10-17T12:42:37Z","year":"2013","citation":{"apa":"Blömer, J., &#38; Liske, G. (2013). Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles. Universität Paderborn.","bibtex":"@article{Blömer_Liske_2013, title={Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles}, publisher={Universität Paderborn}, author={Blömer, Johannes and Liske, Gennadij}, year={2013} }","mla":"Blömer, Johannes, and Gennadij Liske. <i>Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles</i>. Universität Paderborn, 2013.","short":"J. Blömer, G. Liske, (2013).","ama":"Blömer J, Liske G. Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles. 2013.","ieee":"J. Blömer and G. Liske, “Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles.” Universität Paderborn, 2013.","chicago":"Blömer, Johannes, and Gennadij Liske. “Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles.” Universität Paderborn, 2013."},"has_accepted_license":"1","ddc":["040"],"file_date_updated":"2018-03-15T10:35:04Z","project":[{"_id":"1","name":"SFB 901"},{"_id":"13","name":"SFB 901 - Subprojekt C1"},{"name":"SFB 901 - Project Area C","_id":"4"},{"name":"Securing the Financial Cloud","_id":"43"}],"_id":"538","user_id":"25078","department":[{"_id":"64"}],"abstract":[{"text":"We present a new technique to realize attribute-based encryption (ABE) schemes secure in the standard model against chosen-ciphertext attacks (CCA-secure). Our approach is to extend certain concrete chosen-plaintext secure (CPA-secure) ABE schemes to achieve more efficient constructions than the known generic constructions of CCA-secure ABE schemes. We restrict ourselves to the construction of attribute-based key encapsulation mechanisms (KEMs) and present two concrete CCA-secure schemes: a key-policy attribute-based KEM that is based on Goyal's key-policy ABE and a ciphertext-policy attribute-based KEM that is based on Waters' ciphertext-policy ABE. To achieve our goals, we use an appropriate hash function and need to extend the public parameters and the ciphertexts of the underlying CPA-secure encryption schemes only by a single group element. Moreover, we use the same hardness assumptions as the underlying CPA-secure encryption schemes.","lang":"eng"}],"file":[{"file_size":389797,"access_level":"closed","file_name":"538-AB-KEM_01.pdf","file_id":"1292","date_updated":"2018-03-15T10:35:04Z","date_created":"2018-03-15T10:35:04Z","creator":"florida","success":1,"relation":"main_file","content_type":"application/pdf"}],"status":"public","type":"preprint"}]