arXiv subjects

Neha Narula

Publications and source records attributed to Neha Narula.

5 recordsLinked to original sources

arXiv2026

The Hidden Plumbing of Stablecoins: Financial and Technological Risks in the GENIUS Act Era

U.S. dollar stablecoins are increasingly used as payment and settlement instruments beyond cryptocurrency markets. With the enactment of the GENIUS Act in 2025, the United States established the first comprehensive federal framework governing their issuance, backing, and supervision. This paper evaluates the financial, technological, and regulatory risks that may arise as GENIUS-compliant stablecoins scale into mainstream use. We show that maintaining par-value redemption may depend not only on backing-asset quality, but also on the functioning of Treasury and repo markets, the balance-sheet capacity of broker-dealers, and the operational reliability of blockchain-based transaction rails. Even conservatively backed stablecoins can face stress from redemption surges, market-intermediation bottlenecks, or technological disruptions. We argue that durable stability will likely require an integrated approach spanning financial-market infrastructure, prudential regulation, and software governance. While grounded in U.S.\ law, the analysis identifies principles that are relevant for regulators in other jurisdictions developing stablecoin regimes.

econ.GN↗

arXiv2023

A Framework for Programmability in Digital Currency

Programmable money, enabled by digital currencies, facilitates outcomes beyond simple payments by allowing users to attach conditions to the movement of funds through code. However, there is a lack of clarity on defining programmable money, where programmability can be implemented, and the resulting tradeoffs. This paper provides a definition of programmable money with four key components: a format for representing value, a set of programmable instructions, an execution environment providing a coherence guarantee, and rules around permissioning. We discuss programmability primitives, categorizing them into levels based on expressiveness. We outline four locations programmability could be offered - hardcoded into system rules, via client-supplied programs/smart contracts, in client code, or via intermediaries - analyzing benefits and risks of each. For policymakers evaluating central bank digital currencies, we recommend considering these aspects holistically and their interplay with regulation in system design. Our framework and vocabulary enable more nuanced analysis of implementing programmability.

cs.DC↗

arXiv2021

The Power of Random Symmetry-Breaking in Nakamoto Consensus

Nakamoto consensus underlies the security of many of the world's largest cryptocurrencies, such as Bitcoin and Ethereum. Common lore is that Nakamoto consensus only achieves consistency and liveness under a regime where the difficulty of its underlying mining puzzle is very high, negatively impacting overall throughput and latency. In this work, we study Nakamoto consensus under a wide range of puzzle difficulties, including very easy puzzles. We first analyze an adversary-free setting and show that, surprisingly, the common prefix of the blockchain grows quickly even with easy puzzles. In a setting with adversaries, we provide a small backwards-compatible change to Nakamoto consensus to achieve consistency and liveness with easy puzzles. Our insight relies on a careful choice of \emph{symmetry-breaking strategy}, which was significantly underestimated in prior work. We introduce a new method -- \emph{coalescing random walks} -- to analyzing the correctness of Nakamoto consensus under the uniformly-at-random symmetry-breaking strategy. This method is more powerful than existing analysis methods that focus on bounding the number of {\it convergence opportunities}.

cs.DC↗

arXiv2020

A Lower Bound for Byzantine Agreement and Consensus for Adaptive Adversaries using VDFs

Large scale cryptocurrencies require the participation of millions of participants and support economic activity of billions of dollars, which has led to new lines of work in binary Byzantine Agreement (BBA) and consensus. The new work aims to achieve communication-efficiency---given such a large $n$, not everyone can speak during the protocol. Several protocols have achieved consensus with communication-efficiency, even under an adaptive adversary, but they require additional strong assumptions---proof-of-work, memory-erasure, etc. All of these protocols use multicast: every honest replica multicasts messages to all other replicas. Under this model, we provide a new communication-efficient consensus protocol using Verifiable Delay Functions (VDFs) that is secure against adaptive adversaries and does not require the same strong assumptions present in other protocols. A natural question is whether we can extend the synchronous protocols to the partially synchronous setting---in this work, we show that using multicast, we cannot. Furthermore, we cannot achieve always safe communication-efficient protocols (that maintain safety with probability 1) even in the synchronous setting against a static adversary when honest replicas only choose to multicast its messages. Considering these impossibility results, we describe a new communication-efficient BBA protocol in a modified partially synchronous network model which is secure against adaptive adversaries with high probability.

cs.DC↗

arXiv2020

Double-Spend Counterattacks: Threat of Retaliation in Proof-of-Work Systems

Proof-of-Work mining is intended to provide blockchains with robustness against double-spend attacks. However, an economic analysis that follows from Budish (2018), which considers free entry conditions together with the ability to rent sufficient hashrate to conduct an attack, suggests that the resulting block rewards can make an attack cheap. We formalize a defense to double-spend attacks. We show that when the victim can counterattack in the same way as the attacker, this leads to a variation on the classic game-theoretic War of Attrition model. The threat of this kind of counterattack induces a subgame perfect equilibrium in which no attack occurs in the first place.

cs.CR↗