22 research outputs found
Cryptocurrencies and Bitcoin: Charting the Research Landscape
This systematic literature review examines cryptocurrencies (CCs) and Bitcoin. Because cryptocurrency research has not gained much attention from Information Systems (IS) researchers and needs a more vivid discussion, this review summarizes the main concepts of 42 papers and aligns them to IS Research. Although, cryptocurrency research has not reached IS mainstream yet, there is massive potential for multifaceted research ranging from protocol development to designing alternative digital currency schemes. Cryptocurrencies entail a core digital artifact and present a rich phenomenon based on the intertwining of technological artifacts and social contexts. We argue that cryptocurrencies are an alternative payment method that may replace intermediaries with cryptographic methods and should be embedded in the research areas of SIGeBIZ and SIGSEC. At the end of this literature review, we discuss some open research gaps like new business models based on cryptocurrencies or the influence of culture on cryptocurrencies and Bitcoin
Coded Merkle Tree: Solving Data Availability Attacks in Blockchains
In this paper, we propose coded Merkle tree (CMT), a novel hash accumulator
that offers a constant-cost protection against data availability attacks in
blockchains, even if the majority of the network nodes are malicious. A CMT is
constructed using a family of sparse erasure codes on each layer, and is
recovered by iteratively applying a peeling-decoding technique that enables a
compact proof for data availability attack on any layer. Our algorithm enables
any node to verify the full availability of any data block generated by the
system by just downloading a byte block hash commitment and
randomly sampling bytes, where is the size of the data
block. With the help of only one connected honest node in the system, our
method also allows any node to verify any tampering of the coded Merkle tree by
just downloading bytes. We provide a modular library for CMT
in Rust and Python and demonstrate its efficacy inside the Parity Bitcoin
client.Comment: To appear in Financial Cryptography and Data Security (FC) 202
Applying Private Information Retrieval to Lightweight Bitcoin Clients
Lightweight Bitcoin clients execute a Simple Payment Verification (SPV)
protocol to verify the validity of transactions related to a particular user.
Currently, lightweight clients use Bloom filters to significantly reduce the
amount of bandwidth required to validate a particular transaction. This is
despite the fact that research has shown that Bloom filters are insufficient at
preserving the privacy of clients' queries.
In this paper we describe our design of an SPV protocol that leverages
Private Information Retrieval (PIR) to create fully private and performant
queries. We show that our protocol has a low bandwidth and latency cost;
properties that make our protocol a viable alternative for lightweight Bitcoin
clients and other cryptocurrencies with a similar SPV model. In contract to
Bloom filters, our PIR-based approach offers deterministic privacy to the user.
Among our results, we show that in the worst case, clients who would like to
verify 100 transactions occurring in the past week incurs a bandwidth cost of
33.54 MB with an associated latency of approximately 4.8 minutes, when using
our protocol. The same query executed using the Bloom-filter-based SPV protocol
incurs a bandwidth cost of 12.85 MB; this is a modest overhead considering the
privacy guarantees it provides
No Transaction Fees? No Problem! Achieving Fairness in Transaction Fee Mechanism Design
The recently proposed Transaction Fee Mechanism (TFM) literature studies the
strategic interaction between the miner of a block and the transaction creators
(or users) in a blockchain. In a TFM, the miner includes transactions that
maximize its utility while users submit fees for a slot in the block. The
existing TFM literature focuses on satisfying standard incentive properties --
which may limit widespread adoption. We argue that a TFM is "fair" to the
transaction creators if it satisfies specific notions, namely Zero-fee
Transaction Inclusion and Monotonicity. First, we prove that one generally
cannot ensure both these properties and prevent a miner's strategic
manipulation. We also show that existing TFMs either do not satisfy these
notions or do so at a high cost to the miners' utility. As such, we introduce a
novel TFM using on-chain randomness -- rTFM. We prove that rTFM guarantees
incentive compatibility for miners and users while satisfying our novel
fairness constraints.Comment: Extended Abstract (AAMAS '24