259 research outputs found
Overview of Polkadot and its Design Considerations
In this paper we describe the design components of the heterogenous
multi-chain protocol Polkadot and explain how these components help Polkadot
address some of the existing shortcomings of blockchain technologies. At
present, a vast number of blockchain projects have been introduced and employed
with various features that are not necessarily designed to work with each
other. This makes it difficult for users to utilise a large number of
applications on different blockchain projects. Moreover, with the increase in
number of projects the security that each one is providing individually becomes
weaker. Polkadot aims to provide a scalable and interoperable framework for
multiple chains with pooled security that is achieved by the collection of
components described in this paper
Polar Coded Merkle Tree: Mitigating Data Availability Attacks in Blockchain Systems Using Informed Polar Code Design
Data availability (DA) attack is a well-known problem in certain blockchains
where users accept an invalid block with unavailable portions. Previous works
have used LDPC and 2-D Reed Solomon (2DRS) codes with Merkle trees to mitigate
DA attacks. These codes perform well across various metrics such as DA
detection probability and communication cost. However, these codes are
difficult to apply to blockchains with large blocks due to large decoding
complexity and coding fraud proof size (2D-RS codes), and intractable code
guarantees for large code lengths (LDPC codes). In this paper, we focus on
large block size applications and address the above challenges by proposing the
novel Polar Coded Merkle Tree (PCMT): a Merkle tree encoded using the encoding
graph of polar codes. We provide a specialized polar code design algorithm
called Sampling Efficient Freezing and an algorithm to prune the polar encoding
graph. We demonstrate that the PCMT built using the above techniques results in
a better DA detection probability and communication cost compared to LDPC
codes, has a lower coding fraud proof size compared to LDPC and 2D-RS codes,
provides tractable code guarantees at large code lengths (similar to 2D-RS
codes), and has comparable decoding complexity to 2D-RS and LDPC codes.Comment: 36 pages, 10 figures, 2 tables, submitted to IEEE Journal on Selected
Areas in Information Theor
Performance-Based Analysis of Blockchain Scalability Metric
Cryptocurrencies like Bitcoin and Ethereum, are widely known applications of blockchain technology, have drawn much attention and are largely recognized in recent years. Initially Bitcoin and Ethereum processed 7 and 15 Transactions Per Second (TPS) respectively, whereas VISA and Paypal process 1700 and 193 TPS respectively. The biggest challenge to blockchain adoption is scalability, defined as the capacity to change the block size to handle the growing amount of load. This paper attempts to present the existing scalability solutions which are broadly classified into three layers: Layer 0 solutions focus on optimization of propagation protocol for transactions and blocks, Layer 1 solutions are based on the consensus algorithms and data structure, and Layer 2 solutions aims to decrease the load of the primary chain by implementing solutions outside the chain. We present a classification and comparison of existing blockchain scalability solutions based on performance along with their pros and cons
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