International Association
for Cryptologic Research

Non-Interactive Timed Commitment schemes (NITC) allow to open any commitment after a specified delay $t_{\mathrm{fd}}$ . This is useful for sealed bid auctions and as primitive for more complex protocols. We present the first NITC without repeated squaring or theoretical black box algorithms like NIZK proofs or one-way functions. It has fast verification, almost arbitrary delay and satisfies IND-CCA hiding and perfect binding. Additionally, it needs no trusted setup. Our protocol is based on isogenies between supersingular elliptic curves making it presumably quantum secure, and all algorithms have been implemented as part of SQISign or other well-known isogeny-based cryptosystems.