--- _id: '1668' abstract: - lang: eng text: "We revisit the security (as a pseudorandom permutation) of cascading-based constructions for block-cipher key-length extension. Previous works typically considered the extreme case where the adversary is given the entire codebook of the construction, the only complexity measure being the number qe of queries to the underlying ideal block cipher, representing adversary’s secret-key-independent computation. Here, we initiate a systematic study of the more natural case of an adversary restricted to adaptively learning a number qc of plaintext/ciphertext pairs that is less than the entire codebook. For any such qc, we aim to determine the highest number of block-cipher queries qe the adversary can issue without being able to successfully distinguish the construction (under a secret key) from a random permutation.\r\nMore concretely, we show the following results for key-length extension schemes using a block cipher with n-bit blocks and κ-bit keys:\r\nPlain cascades of length ℓ=2r+1 are secure whenever qcqre≪2r(κ+n), qc≪2κ and qe≪22κ. The bound for r=1 also applies to two-key triple encryption (as used within Triple DES).\r\nThe r-round XOR-cascade is secure as long as qcqre≪2r(κ+n), matching an attack by Gaži (CRYPTO 2013).\r\nWe fully characterize the security of Gaži and Tessaro’s two-call " alternative_title: - LNCS author: - first_name: Peter full_name: Gazi, Peter id: 3E0BFE38-F248-11E8-B48F-1D18A9856A87 last_name: Gazi - first_name: Jooyoung full_name: Lee, Jooyoung last_name: Lee - first_name: Yannick full_name: Seurin, Yannick last_name: Seurin - first_name: John full_name: Steinberger, John last_name: Steinberger - first_name: Stefano full_name: Tessaro, Stefano last_name: Tessaro citation: ama: 'Gazi P, Lee J, Seurin Y, Steinberger J, Tessaro S. Relaxing full-codebook security: A refined analysis of key-length extension schemes. 2015;9054:319-341. doi:10.1007/978-3-662-48116-5_16' apa: 'Gazi, P., Lee, J., Seurin, Y., Steinberger, J., & Tessaro, S. (2015). Relaxing full-codebook security: A refined analysis of key-length extension schemes. Presented at the FSE: Fast Software Encryption, Istanbul, Turkey: Springer. https://doi.org/10.1007/978-3-662-48116-5_16' chicago: 'Gazi, Peter, Jooyoung Lee, Yannick Seurin, John Steinberger, and Stefano Tessaro. “Relaxing Full-Codebook Security: A Refined Analysis of Key-Length Extension Schemes.” Lecture Notes in Computer Science. Springer, 2015. https://doi.org/10.1007/978-3-662-48116-5_16.' ieee: 'P. Gazi, J. Lee, Y. Seurin, J. Steinberger, and S. Tessaro, “Relaxing full-codebook security: A refined analysis of key-length extension schemes,” vol. 9054. Springer, pp. 319–341, 2015.' ista: 'Gazi P, Lee J, Seurin Y, Steinberger J, Tessaro S. 2015. Relaxing full-codebook security: A refined analysis of key-length extension schemes. 9054, 319–341.' mla: 'Gazi, Peter, et al. Relaxing Full-Codebook Security: A Refined Analysis of Key-Length Extension Schemes. Vol. 9054, Springer, 2015, pp. 319–41, doi:10.1007/978-3-662-48116-5_16.' short: P. Gazi, J. Lee, Y. Seurin, J. Steinberger, S. Tessaro, 9054 (2015) 319–341. conference: end_date: 2015-03-11 location: Istanbul, Turkey name: 'FSE: Fast Software Encryption' start_date: 2015-03-08 date_created: 2018-12-11T11:53:22Z date_published: 2015-08-12T00:00:00Z date_updated: 2020-08-11T10:09:26Z day: '12' department: - _id: KrPi doi: 10.1007/978-3-662-48116-5_16 ec_funded: 1 intvolume: ' 9054' language: - iso: eng main_file_link: - open_access: '1' url: http://eprint.iacr.org/2015/397 month: '08' oa: 1 oa_version: Submitted Version page: 319 - 341 project: - _id: 258C570E-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '259668' name: Provable Security for Physical Cryptography publication_status: published publisher: Springer publist_id: '5481' quality_controlled: '1' scopus_import: 1 series_title: Lecture Notes in Computer Science status: public title: 'Relaxing full-codebook security: A refined analysis of key-length extension schemes' type: conference user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 9054 year: '2015' ...