International Association for Cryptologic Research

International Association
for Cryptologic Research


Monotone-Policy Aggregate Signatures

Maya Farber Brodsky , Tel Aviv University
Arka Rai Choudhuri , NTT Research
Abhishek Jain , NTT Research and Johns Hopkins University
Omer Paneth , Tel Aviv University
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Conference: EUROCRYPT 2024
Abstract: The notion of aggregate signatures allows for combining signatures from different parties into a short certificate that attests that *all* parties signed a message. In this work, we lift this notion to capture different, more expressive signing policies. For example, we can certify that a message was signed by a (weighted) threshold of signers. We present the first constructions of aggregate signatures for monotone policies based on standard polynomial-time cryptographic assumptions. The aggregate signatures in our schemes are succinct, i.e., their size is *independent* of the number of signers. Moreover, verification is also succinct if all parties sign the same message (or if the messages have a succinct representation). All prior work requires either interaction between the parties or non-standard assumptions (that imply SNARKs for NP). Our signature schemes are based on non-interactive batch arguments (BARGs) for monotone policies [Brakerski-Brodsky-Kalai-Lombardi-Paneth, Crypto'23]. In contrast to previous constructions, our BARGs satisfy a new notion of *adaptive* security which is instrumental to our application. Our new BARGs for monotone policies can be constructed from standard BARGs and other standard assumptions.
  title={Monotone-Policy Aggregate Signatures},
  author={Maya Farber Brodsky and Arka Rai Choudhuri and Abhishek Jain and Omer Paneth},