Secure Database Commitments and Universal Arguments of Quasi Knowledge
In this paper, the authors focus on a simple database commitment functionality where besides the standard security properties, one would like to hide the size of the input of the sender. Hiding the size of the input of a player is a critical requirement in some applications, and relatively few works have considered it. Notable exceptions are the work on zero-knowledge sets introduced in [MRK03], and recent work on size-hiding private set intersection [ADCT11]. However, neither of these achieves a secure computation (i.e., a reduction of a real-world attack of a malicious adversary into an ideal-world attack) of the proposed functionality.