On today\u2019s open computing platforms, attackers can often
\nextract sensitive data from a program\u2019s stack, heap, or files. To address
\nthis problem, we designed and implemented a new primitive that helps
\nprovide better security for ciphers that use keys stored in easily accessible
\nlocations. Given a particular symmetric key, our approach generates two
\nfunctions for encryption and decryption: The short-key function uses the
\noriginal key, while the functionally equivalent long-key version works with
\nan arbitrarily long key derived from the short key. On common PC architectures,
\nsuch a long key normally does not fit in stack frames or cache
\nblocks, forcing an attacker to search memory space. Even if extracted
\nfrom memory, the long key is neither easily compressible nor useful in
\nrecovering the short key. Using a pseudorandom generator and additional
\nnovel software-protection techniques, we show how to implement
\nthis construction securely for AES. Potential applications include whitebox
\nciphers, DRM schemes, software smartcards, and challenge-response
\nauthentication, as well as any scenario where a key of controllable length
\nis useful to enforce desired security properties.<\/p>\n","protected":false},"excerpt":{"rendered":"
On today\u2019s open computing platforms, attackers can often extract sensitive data from a program\u2019s stack, heap, or files. To address this problem, we designed and implemented a new primitive that helps provide better security for ciphers that use keys stored in easily accessible locations. Given a particular symmetric key, our approach generates two functions for […]<\/p>\n","protected":false},"featured_media":0,"template":"","meta":{"msr-url-field":"","msr-podcast-episode":"","msrModifiedDate":"","msrModifiedDateEnabled":false,"ep_exclude_from_search":false,"footnotes":""},"msr-content-type":[3],"msr-research-highlight":[],"research-area":[],"msr-publication-type":[193716],"msr-product-type":[],"msr-focus-area":[],"msr-platform":[],"msr-download-source":[],"msr-locale":[268875],"msr-field-of-study":[],"msr-conference":[],"msr-journal":[],"msr-impact-theme":[],"msr-pillar":[],"class_list":["post-155750","msr-research-item","type-msr-research-item","status-publish","hentry","msr-locale-en_us"],"msr_publishername":"","msr_edition":"3rd International Workshop on Security (IWSEC 2008)","msr_affiliation":"","msr_published_date":"2008-11-01","msr_host":"","msr_duration":"","msr_version":"","msr_speaker":"","msr_other_contributors":"","msr_booktitle":"3rd International Workshop 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