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SCP Security Seminar

SCP Title Card

Speaker: Akshaya Kumar, Ph.D. Student 

Title: Memory-Tight Multi-Challenge Security of Public-Key Encryption


Abstract: We give the first examples of public-key encryption schemes which can be proven to achieve multi-challenge, multi-user CCA security via reductions that are tight in time, advantage, and memory. Our constructions are obtained by applying the KEM-DEM paradigm to variants of Hashed ElGamal and the Fujisaki-Okamoto transformation that are augmented by adding uniformly random strings to their ciphertexts and/or keys. Our proofs for the augmented ECIES version of Hashed-ElGamal make use of a new computational Diffie-Hellman assumption wherein the adversary is given access to a pairing to a random group, which we believe may be of independent interest.


Bio: Akshaya Kumar is a first-year Ph.D. student in Computer Science at the Georgia Institute of Technology's School of Cybersecurity and Privacy where she is advised by Professor Joseph Jaeger. Her research interests include cryptography, information security, and generally, theoretical computer science. Her most recent work focuses on provable security in the memory-aware setting. Her paper on memory-tight proofs for public key encryption schemes was recently accepted at Asiacrypt 2022. She is a part of The Association for Women in Mathematics (AWM), an initiative that promotes women in mathematics.