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DTSTART;TZID=America/Toronto:20251003T153000
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URL:https://uwaterloo.ca/combinatorics-and-optimization/events/tutte-colloq
 uium-mojtaba-fadavi
SUMMARY:Tutte Colloquium - Mojtaba Fadavi
CLASS:PUBLIC
DESCRIPTION:TITLE: Hash-Based Digital Signatures: An Overview with a Focus
  on\nGroup Signature Schemes\n\nSPEAKER:\n Mojtaba Fadavi\n\nAFFILIATION:\
 n University of Waterloo\n\nLOCATION:\n MC 5501\n\nABSTRACT: Digital sign
 ature schemes are crucial for secure\ncommunication\, authentication\, and
  data integrity in applications like\nsecure email\, financial transaction
 s\, and blockchain systems. However\,\nclassical schemes (e.g.\, RSA\, ECD
 SA\, Schnorr) are vulnerable to\nquantum attacks\, driving the shift to po
 st-quantum cryptographic\nalternatives.\n\nHash-based signature schemes ar
 e key because their security relies on\ncryptographic hash functions\, not
  number-theoretic problems\, making\nthem more robust for post-quantum sec
 urity. These schemes are\ncategorized into one-time\, few-time\, and many-
 time signatures. To\ndate\, NIST has standardized three many-time hash-bas
 ed schemes: LMS\,\nXMSS\, and SPHINCS+.\n\nGroup Signature Schemes (GSS) e
 nable anonymous message signing on\nbehalf of a group\, with a designated 
 authority able to reveal the\nsigner's identity when necessary. This featu
 re is critical in\nprivacy-preserving applications like anonymous attestat
 ions and\nreputation systems. Fully dynamic GSSs are particularly valuable
  as\nthey allow users to join or be revoked without system-wide updates. 
 \n\nIn this talk\, I will review key hash-based group signature schemes\,\
 nincluding G-Merkle\, DGM\, DGMT\, and SPHINX-in-the-Head\, discussing\nth
 eir limitations in scalability and efficiency. I will then introduce\nDGSP
 \, our new scalable and efficient fully dynamic GSS\, and compare it\nwith
  existing post-quantum alternatives to highlight its advantages.
DTSTAMP:20260402T151807Z
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