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DTEND:20210727T120000Z
UID:679f0763e42ce79273be2c4118376dea-180
DTSTAMP:19700101T120009Z
DESCRIPTION:Locally Reconstructable Non-Malleable Secret Sharing
URL;VALUE=URI:https://www.csa.iisc.ac.in/newweb/event/180/locally-reconstructable-non-malleable-secret-sharing/
SUMMARY:Non-malleable secret sharing (NMSS) schemes, introduced by Goyal and Kumar (STOC 2018), ensure that a secret m can be distributed into shares m1,...,mn (for some n), such that any t (a parameter <= n) shares can be reconstructed to recover the secret m, any t-1 shares doesnt leak information about m and even if the shares that are used for reconstruction are tampered, it is guaranteed that the reconstruction of these tampered shares will either result in the original m or something independent of m. Since their introduction, non-malleable secret sharing schemes sparked a very impressive line of research.
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In this talk, we present a new feature of local reconstructablility in NMSS, which allows reconstruction of any portion of a secret by reading just a few locations of the shares. This is a useful feature, especially when the secret is long or when the shares are stored in a distributed manner on a communication network. In this talk, we give a compiler that takes in any non-malleable secret sharing scheme and compiles it into a locally reconstructable non-malleable secret sharing scheme. To secret share a message consisting of k blocks of length r each, our scheme would only require reading r + log k  bits (in addition to a few more bits, whose quantity is independent of r and k) from each partys share (of a reconstruction set) to locally reconstruct a single block of the message.  
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Microsoft teams link:
<a href="https://teams.microsoft.com/l/meetup-join/19%3ameeting_MzNjOGVkNzgtNTM5Zi00OWRlLWJkYWItYWNjMjI4ZGI1NzJi%40thread.v2/0?context=%7b%22Tid%22%3a%226f15cd97-f6a7-41e3-b2c5-ad4193976476%22%2c%22Oid%22%3a%225f3273b8-8838-46b7-b675-b1e9eab4d8ef%22%7d">https://teams.microsoft.com/l/meetup-join/19%3ameeting_MzNjOGVkNzgtNTM5Zi00OWRlLWJkYWItYWNjMjI4ZGI1NzJi%40thread.v2/0?context=%7b%22Tid%22%3a%226f15cd97-f6a7-41e3-b2c5-ad4193976476%22%2c%22Oid%22%3a%225f3273b8-8838-46b7-b675-b1e9eab4d8ef%22%7d</a>
DTSTART:20210727T120000Z
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