中央研究院 資訊科學研究所

Threshold cryptography is a standard technique for distributing trust by splitting cryptographic keys into multiple shares held by different parties. Normally, in threshold cryptography, we assume there is a trusted dealer who distributes the shares to different parties or that the parties participate in an interactive distributed key-generation protocol to derive their individual shares. In recent years, several works have proposed a new model where users independently choose their public key, and there is a deterministic function that derives the joint public key associated with a group of users from their individual keys. Schemes with this silent (i.e., non-interactive) setup allow us to have the utility of threshold cryptography without needing a trusted dealer or an interactive setup. In this talk, I will describe a new pairing-based approach for constructing threshold signatures and encryption schemes with silent setup. Our techniques allow us to support expressive policies (including threshold policies) while only relying on simple algebraic tools. This yields constructions with shorter signatures and ciphertexts compared to previous pairing-based constructions. Concretely, the signature size in our threshold signature scheme is 3 group elements and the ciphertext size in our threshold encryption scheme is 4 group elements.

Prof. David Wu 為美國德州大學奧斯汀分校（University of Texas at Austin）電腦科學系助理教授，是密碼學與資訊安全領域具影響力的年輕學者之一。其研究專長為密碼學與安全計算，致力於發展可在不洩露資料內容的情況下進行安全運算的技術，對隱私保護與資料安全具有重要貢獻。Prof. Wu 的研究成果多次發表於國際頂尖學術會議，並獲得多項學術獎項與研究補助。其學術論文已被引用超過七千次，顯示其研究在密碼學與資訊安全領域具有高度影響力。邀請其進行專題演講，將有助於促進相關領域之學術交流與研究發展。

相關榮譽如下：
*      loan Research Fellowship（2025）：國際知名學術獎項，頒給北美最具潛力的年輕學者，被視為未來學術領袖的重要指標。       
*      NSF CAREER Award（2021）：美國國家科學基金會（NSF）頒發給年輕教授最具代表性的研究獎項之一，表彰具高度研究潛力之學者。  
*      Microsoft Research Faculty Fellowship（2021）：由微軟研究院頒發的學術獎助，支持在電腦科學領域具有卓越研究成果的青年學者。 
*      Google Research Scholar Award（2022）：Google 提供之國際研究獎助，表彰在相關研究領域具有創新貢獻的學者。       
*      Best Paper Award, CRYPTO（2022）：CRYPTO 為全球密碼學領域最頂尖的國際會議之一，最佳論文獎代表當年最具影響力的研究成果之一。       
*      U.S./U.K. Privacy-Enhancing Technologies Prize Challenge（2023）：由美國與英國政府主辦之國際競賽，其團隊於兩階段競賽中分別獲得第一名與第二名。