Multi-key Security: The Even-Mansour Construction Revisited

International audienceAt ASIACRYPT 1991, Even and Mansour introduced a block cipher construction based on a single permutation. Their construction has since been lauded for its simplicity, yet also criticized for not providing the same security as other block ciphers against generic attacks. In this paper, we prove that if a small number of plaintexts are encrypted under multiple independent keys, the Even-Mansour construction surprisingly offers similar security as an ideal block cipher with the same block and key size. Note that this multi-key setting is of high practical relevance, as real-world implementations often allow frequent rekeying. We hope that the results in this paper will further encourage the use of the Even-Mansour construction, especially when a secure and efficient implementation of a key schedule would result in significant overhead

A hybrid nanosensor for TNT vapor detection

Real-time detection of trace chemicals, such as explosives, in a complex environment containing various interferents has been a difficult challenge. We describe here a hybrid nanosensor based on the electrochemical reduction of TNT and the interaction of the reduction products with conducting polymer nanojunctions in an ionic liquid. The sensor simultaneously measures the electrochemical current from the reduction of TNT and the conductance change of the polymer nanojunction caused from the reduction product. The hybrid detection mechanism, together with the unique selective preconcentration capability of the ionic liquid, provides a selective, fast, and sensitive detection of TNT. The sensor, in its current form, is capable of detecting parts-per-trillion level TNT in the presence of various interferents within a few minutes.Fil: Aguilar, Alvaro Díaz. Arizona State University; Estados UnidosFil: Forzani, Erica S.. Arizona State University; Estados UnidosFil: Leright, Mathew. Arizona State University; Estados UnidosFil: Tsow, Francis. Arizona State University; Estados UnidosFil: Cagan, Avi. Arizona State University; Estados UnidosFil: Iglesias, Rodrigo Alejandro. Arizona State University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Nagahara, Larry A.. Motorola Laboratories; Estados UnidosFil: Amlani, Islamshah. Motorola Laboratories; Estados UnidosFil: Tsui, Raymond. Motorola Laboratories; Estados UnidosFil: Tao, N.J.. Arizona State University; Estados Unido