On Scaling LT-Coded Blockchains in Heterogeneous Networks and their Vulnerabilities to DoS Threats

2024-02-08

AI Summary

LT-coded blockchains in heterogeneous networks face dual scalability and security challenges: conventional decoders (e.g., belief propagation, Gaussian elimination) cannot adapt to diverse node computational/download capabilities, and existing works lack security modeling of capability-aware denial-of-service (DoS) attacks. Method: We propose the first hybrid LT decoder family for heterogeneous networks, dynamically combining BP and Gaussian elimination; systematically characterize and model non-blind DoS attacks targeting decoding-weak nodes; and integrate blockchain archival analysis with selective block-level interference. Contribution/Results: Our approach significantly reduces average decoding overhead across heterogeneous nodes and achieves network-access blocking efficacy comparable to blind DoS attacks—yet with substantially lower resource consumption—thereby filling a critical gap in coded blockchain security modeling.

Technology Category

• Search and Optimization: Distributed Search
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Machine Learning: Hardware-aware ML

Application Category

• Security and Privacy: Blockchains and distributed ledgers
• Economics, Online Markets and Human Computation: Economic aspects of blockchain and cryptocurrencies
• Graph Algorithms and Modeling for the Web: Algorithms and analysis for incomplete, noisy, or partially observed Web-related graphs

Abstract

Coded blockchains have acquired prominence as a promising solution to reduce storage costs and facilitate scalability. Within this class, Luby Transform (LT) coded blockchains are an appealing choice for scalability owing to the availability of a wide range of low-complexity decoders. In the first part of this work, we identify that traditional LT decoders like Belief Propagation and On-the-Fly Gaussian Elimination may not be optimal for heterogeneous networks with nodes that have varying computational and download capabilities. To address this, we introduce a family of hybrid decoders for LT codes and propose optimal operating regimes for them to recover the blockchain at the lowest decoding cost. While LT coded blockchain architecture has been studied from the aspects of storage savings and scalability, not much is known in terms of its security vulnerabilities. Pointing at this research gap, in the second part, we present novel denial-of-service threats on LT coded blockchains that target nodes with specific decoding capabilities, preventing them from joining the network. Our proposed threats are non-oblivious in nature, wherein adversaries gain access to the archived blocks, and choose to execute their attack on a subset of them based on underlying coding scheme. We show that our optimized threats can achieve the same level of damage as that of blind attacks, however, with limited amount of resources. Overall, this is the first work of its kind that opens up new questions on designing coded blockchains to jointly provide storage savings, scalability and also resilience to optimized threats.

Problem

• Optimizing LT decoders for heterogeneous networks with varying node capabilities
• Identifying novel DoS threats targeting specific nodes in LT coded blockchains
• Developing resilient coded blockchain designs against optimized resource-efficient attacks

Innovation

• Hybrid decoders optimize LT codes for heterogeneous networks
• Non-oblivious DoS threats target specific decoding capabilities
• Optimized attacks achieve high damage with limited resources