Zimand [24] presented simple constructions of locally computable strong extractors whose analysis relies on the direct product theorem for one-way functions and on the Blum-Micali-Yao generator. For N -bit sources of entropy γN , his extractor has seed O(logN) and extracts N random bits. We show that his construction can be analyzed based solely on the direct product theorem for general functio...

An extractor is a function that receives some randomness and either “improves” it or produces “new” randomness. There are statistical and algorithmical specifications of this notion. We study an algorithmical one called Kolmogorov extractors and modify it to resourcebounded version of Kolmogorov complexity. Following Zimand we prove the existence of such objects with certain parameters. The uti...

Fuzzy extractors derive strong keys from noisy sources. Their security is defined informationtheoretically, which limits the length of the derived key, sometimes making it too short to be useful. We ask whether it is possible to obtain longer keys by considering computational security, and show the following. • Negative Result: Noise tolerance in fuzzy extractors is usually achieved using an in...

We study the suitability of common pseudorandomness modes associated with cryptographic hash functions and block ciphers (CBCMAC, Cascade and HMAC) for the task of “randomness extraction”, namely, the derivation of keying material from semi-secret and/or semirandom sources. Important applications for such extractors include the derivation of strong cryptographic keys from non-uniform sources of...

Fuzzy extractors (Dodis et al., Eurocrypt 2004) convert repeated noisy readings of a high-entropy secret into the same uniformly distributed key. To eliminate noise, they require an initial enrollment phase that takes the first noisy reading of the secret and produces a nonsecret helper string to be used in subsequent readings. This helper string reduces the entropy of the original secret—in th...

Information Extraction (IE) is the key technology enabling analytics over unstructured and semi-structured data. Not surprisingly, it is becoming a critical building block for a wide range of emerging applications. To satisfy the rising demands for information extraction in real-world applications, it is crucial to lower the barrier to entry for IE development and enable users with general comp...

We show a reduction from explicit two-source extractors with small error and arbitrarily small constant entropy rate to the existence of explicit t-non-malleable extractors with a small seed length. Previously, such a reduction was known either when one source had entropy rate above half [Raz05] or for general entropy rates but only for large error [CZ16]. As in previous reductions we start wit...