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We present ShorTor, a protocol for reducing latency on the Tor network. ShorTor uses multi-hop overlay routing, a technique typically employed by content delivery networks, to influence the route Tor traffic takes across the internet. ShorTor functions as an overlay on top of onion routing-Tor's existing routing protocol and is run by Tor relays, making it independent of the path selection performed by Tor clients. As such, ShorTor reduces latency while preserving Tor's existing security properties. Specifically, the routes taken in ShorTor are in no way correlated to either the Tor user or their destination, including the geographic location of either party. We analyze the security of ShorTor using the AnoA framework, showing that ShorTor maintains all of Tor's anonymity guarantees. We augment our theoretical claims with an empirical analysis. To evaluate ShorTor's performance, we collect a real-world dataset of over 400,000 latency measurements between the 1,000 most popular Tor relays, which collectively see the vast majority of Tor traffic. With this data, we identify pairs of relays that could benefit from ShorTor: that is, two relays where introducing an additional intermediate network hop results in lower latency than the direct route between them. We use our measurement dataset to simulate the impact on end users by applying ShorTor to two million Tor circuits chosen according to Tor's specification. ShorTor reduces the latency for the 99th percentile of relay pairs in Tor by 148 ms. Similarly, ShorTor reduces the latency of Tor circuits by 122 ms at the 99th percentile. In practice, this translates to ShorTor truncating tail latencies for Tor which has a direct impact on page load times and, consequently, user experience on the Tor browser.

We present Judge, Jury and Encryptioner (JJE) an exceptional access scheme for unlocking devices that does not give unilateral power to any single authority. JJE achieves this by placing final approval to unlock a device in the hands of peer devices. JJE distributes maintenance of the protocol across a network of "custodians" such as courts, government agencies, civil rights watchdogs, and academic institutions. Unlock requests, however, can only be approved by a randomly selected set of recently active peer devices that must be physically located by law enforcement in order to gain access to the locked device. This requires that law enforcement expend both human and monetary resources and pay a "social cost" in order to find and request the participation of random device owners in the unlock process. Compared to other proposed exceptional access schemes, we believe that JJE mitigates the risk of mass surveillance, law enforcement abuse, and vulnerability to unlawful attackers. While we propose a concrete construction, our primary goal with JJE is to spur discussion on ethical exceptional access schemes that balance privacy of individuals and the desires for law enforcement. JJE transparently reveals the use of exceptional access to the public and enforces a fixed social cost that, we believe, can be an effective deterrent to mass surveillance and abuse.

We present STAR: a novel system aimed at solving the complex issue of "p-hacking" and false discoveries in scientific studies. STAR provides a concrete way for ensuring the application of false discovery control procedures in hypothesis testing, using mathematically provable guarantees, with the goal of reducing the risk of data dredging. STAR generates an efficiently auditable certificate which attests to the validity of each statistical test performed on a dataset. STAR achieves this by using several cryptographic techniques which are combined specifically for this purpose. Under-the-hood, STAR uses a decentralized set of authorities (e.g., research institutions), secure computation techniques, and an append-only ledger which together enable auditing of scientific claims by 3rd parties and matches real world trust assumptions. We implement and evaluate a construction of STAR using the Microsoft SEAL encryption library and SPDZ multi-party computation protocol. Our experimental evaluation demonstrates the practicality of STAR in multiple real world scenarios as a system for certifying scientific discoveries in a tamper-proof way.