caa a22 4500 47582704X CHVBK 20180406123831.0 cr unu---uuuuu 170329e20000101xx s 000 0 eng 10.1007/s001459910004 doi (NATIONALLICENCE)springer-10.1007/s001459910004 Maintaining Authenticated Communication in the Presence of Break-Ins [Elektronische Daten] [Ran Canetti, Shai Halevi, Amir Herzberg] Abstract. : We study the problem of maintaining authenticated communication over untrusted communication channels, in a scenario where the communicating parties may be occasionally and repeatedly broken into for transient periods of time. Once a party is broken into, its cryptographic keys are exposed and perhaps modified. Yet, when aided by other parties it should be able to regain its ability to communicate in an authenticated way. We present a mathematical model for this highly adversarial setting, exhibiting salient properties and parameters, and then describe a practically appealing protocol for solving this problem. A key element in our solution is devising a proactive distributed signature (PDS) scheme in our model. The PDS schemes known in the literature are designed for a model where authenticated communication is available. We therefore show how these schemes can be modified to work in our model, where no such primitives are available a priori. In the process of devising these schemes, we also present a new definition of PDS schemes (and of distributed signature schemes in general). This definition may be of independent interest. International Association for Cryptologic Research, 2000 Key words. Authentication protocols, Break-ins, Recovery, Distributed signatures, Proactive signatures, Proactive protocols nationallicence Canetti Ran IBM T.J. Watson Research, Yorktown Heights, PO Box 704, 10598, NY, U.S.A. aut Halevi Shai IBM T.J. Watson Research, Yorktown Heights, PO Box 704, 10598, NY, U.S.A. aut Herzberg Amir IBM Haifa Research Lab - Tel Aviv Annex 2, Weizmann Institute, Tel Aviv, Israel aut Journal of Cryptology Springer New York 13/1(2000-01-01), 61-105 0933-2790 13:1<61 2000 13 145 https://doi.org/10.1007/s001459910004 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s001459910004 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Canetti Ran IBM T.J. Watson Research, Yorktown Heights, PO Box 704, 10598, NY, U.S.A aut NATIONALLICENCE 700 1- Halevi Shai IBM T.J. Watson Research, Yorktown Heights, PO Box 704, 10598, NY, U.S.A aut NATIONALLICENCE 700 1- Herzberg Amir IBM Haifa Research Lab - Tel Aviv Annex 2, Weizmann Institute, Tel Aviv, Israel aut NATIONALLICENCE 773 0- Journal of Cryptology Springer New York 13/1(2000-01-01), 61-105 0933-2790 13:1<61 2000 13 145 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer