Certified Randomness with Optimal Rate

The generation of certified random bits is an emerging near-term application of quantum computers. Potential applications, such as randomness beacons and CRS generation, require nearly uniform randomness, whose rate the ratio of min-entropy to bitlength is 1. However, existing protocols for...

Classical Verifier Position Verification from Non-Local Games

Secure position verification certifies that a remote prover occupies a claimed location, a task that is provably impossible with classical resources alone against colluding adversaries. Most existing quantum position verification schemes require transmitting quantum states between verifiers and...

Quantum Time-Lock Puzzles in the Quantum Random Oracle Model

A time-lock puzzle allows a sender to hide a message in a puzzle such that recovering the message requires substantially more sequential computation than the time required to generate the puzzle, even when parallel computation is allowed. Applications of time-lock puzzles include timed-release...