Theory Seminar
Welcome to the Fall 2026 series of the University of Massachusetts Computer Science Theory Seminar. The seminar is noon-1 pm on Wednesdays in Room 140, in the Computer Science Building (CSB) at UMass Amherst, and is free and open to the public. The faculty host this semester is Andrew McGregor. If you are interested in giving a talk, please email the faculty host, or Adam Lechowicz. Note that in addition to being a public lecture series, this is also a one-credit graduate seminar (CompSci 891M) that can be taken repeatedly for credit.
Fall 2026 Schedule of Speakers
NOTE: In order to ensure you get weekly updates for all the talks, please make sure you are part of the seminars@cs.umass.edu mailing list. If you wish to give a talk, or would like to nominate someone to give one, please email us to let us know!
Organizational Meeting
Wednesday, September 9th @ noon
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TBA (TBA) – Wednesday, September 16 @ noon
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Distance-Preserving Encryption for Natural-Language Embedding Vectors
Charanjit S. Jutla (IBM T. J. Watson Research Center) – Wednesday, September 23 @ noon
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We study symmetric encryption of high-dimensional embedding vectors that preserves enough geometric structure to support (approximate) nearest-neighbor search on ciphertexts. Since usual chosen-plaintext attack (CPA) model security is unlikely, we focus on restricted attacks such as single snapshot attacks with limited known plaintexts. Our scheme encrypts a vector by sending it through a secret Isometric transform followed by adding noise, a la LWE. Because a rotation preserves all pairwise distances, the residual structure available to a snapshot adversary is exactly a distance-labeled graph, so plain- text recovery reduces to a constrained, average-case subgraph-isomorphism problem. Our main technical contribution is evidence that this problem resists the dominant algorithmic paradigm, i.e. Ullman’s pruning-and-backtracking.
Bio
Charanjit Jutla received his PhD in Computer Science from the University of Texas at Austin in 1990. Since then he has been a Research Staff Member at the IBM T. J. Watson Research Center. His research focuses in the fields of Cryptography, Coding Theory and Complexity Theory. Among his various contributions to cryptography, he invented the first single-pass Authenticated Encryption Scheme. He is the author of several papers and patents in the field of cryptography. He has been on the program committee of various international cryptography conferences.
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Margalit Glasgow (MIT) – Wednesday, September 30 @ noon
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TBA (TBA) – Wednesday, October 7 @ noon
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TBA (TBA) – Wednesday, October 14 @ noon
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TBA (TBA) – Wednesday, October 21 @ noon
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TBA (TBA) – Wednesday, October 28 @ noon
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TBA (TBA) – Wednesday, November 4 @ noon
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TBA (TBA) – Wednesday, November 11 @ noon
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TBA (TBA) – Wednesday, November 18 @ noon
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No Meeting – Thanksgiving Break
Wednesday, November 25 @ noon
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TBA (TBA) – Wednesday, December 2 @ noon
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TBA (TBA) – Wednesday, December 9 @ noon
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