On the Adaptive Security of Key-Unique Threshold Signatures
summary
Proves two impossibility results about key-unique threshold signatures using metareduction arguments: under any non-interactive computational assumption one cannot get adaptively secure reductions with better tightness than trivial guessing; a case study on FROST shows static security from the algebraic one‑more DL but adaptive security up to t/2 corruptions uses the same model while full t corruptions requires the algebraic group model plus a new low‑dimensional vector representation assumption.
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chapters (9)
- 0:00Adaptive security in threshold sigs
- 1:28Threshold signatures and uses
- 3:58Static vs adaptive security
- 7:03Adaptive security in practice
- 12:48FROST threshold sigs case study
- 18:09Key-unique threshold sigs
- 22:07Impossibility results for proofs
- 27:35Key-unique vs non-key-unique schemes
- 29:50Summary and future directions
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