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. 2023 Apr 6;13(1):5664.
doi: 10.1038/s41598-023-32701-6.

Quantum-resistance in blockchain networks

Marcos Allende  1   2 , Diego López León  1   2 , Sergio Cerón  1   2 , Adrián Pareja  1   2 , Erick Pacheco  1   2 , Antonio Leal  1   2 , Marcelo Da Silva  1   2 , Alejandro Pardo  1   2 , Duncan Jones  3 , David J Worrall  3 , Ben Merriman  3 , Jonathan Gilmore  3 , Nick Kitchener  3 , Salvador E Venegas-Andraca  4
Affiliations

Quantum-resistance in blockchain networks

Marcos Allende et al. Sci Rep. .

Abstract

The advent of quantum computing threatens blockchain protocols and networks because they utilize non-quantum resistant cryptographic algorithms. When quantum computers become robust enough to run Shor's algorithm on a large scale, the most used asymmetric algorithms, utilized for digital signatures and message encryption, such as RSA, (EC)DSA, and (EC)DH, will be no longer secure. Quantum computers will be able to break them within a short period of time. Similarly, Grover's algorithm concedes a quadratic advantage for mining blocks in certain consensus protocols such as proof of work. Today, there are hundreds of billions of dollars denominated in cryptocurrencies and other digital assets that rely on blockchain ledgers as well as thousands of blockchain-based applications storing value in blockchain networks. Cryptocurrencies and blockchain-based applications require solutions that guarantee quantum resistance in order to preserve the integrity of data and assets in these public and immutable ledgers. The quantum threat and some potential solutions are well understood and presented in the literature. However, most proposals are theoretical, require large QKD networks, or propose new quantum-resistant blockchain networks to be built from scratch. Our work, which is presented in this paper, is pioneer in proposing an end-to-end framework for post-quantum blockchain networks that can be applied to existing blockchain to achieve quantum-resistance. We have developed an open-source implementation in an Ethereum-based (i.e., EVM compatible) network that can be extended to other existing blockchains. For the implementation we have (i) used quantum entropy to generate post-quantum key pairs, (ii) established post-quantum TLS connections and X.509 certificates to secure the exchange of information between blockchain nodes over the internet without needing a large QKD network, (iii) introduced a post-quantum second signature in transactions using Falcon-512 post-quantum keys, and (iv) developed the first on-chain verification of post-quantum signatures using three different mechanisms that are compared and analyzed: Solidity smart-contracts run by the validators for each transaction, modified EVM Opcode, and precompiled smart contracts.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
High-level schema of the first connection between the remote source of entropy and the blockchain node.
Figure 2
Figure 2
Detailed flows describing the generation and consumption of entropy on demand by the Open SSL.
Figure 3
Figure 3
Comparison between Falcon and crystals-dilithium algorithms.
Figure 4
Figure 4
High level diagram of the post-quantum certification and on-chain registration of an entity.
Figure 5
Figure 5
High level diagram of the post-quantum certification and on-chain registration of an entity.
Figure 6
Figure 6
Bytes per package.
Figure 7
Figure 7
High level diagram presenting the different components from the DApp (it can also be an app or any application connected to the writer node and generating transactions) and the smart contract that it is calling.
Figure 8
Figure 8
High level diagram illustrating the flows from the generation of a transaction to the incorporation of that transaction to the transaction pool of a node, after validating the post-quantum signature.
Figure 9
Figure 9
High level function hierarchy of Falcon highlighting the necessary calls for verification.
Figure 10
Figure 10
Gas consumption by the on-chain verification of Falcon-512 using the Solidity smart contract.
Figure 11
Figure 11
EVM virtual machine-based signature validation support.
Figure 12
Figure 12
Pros and Cons of Pure Solidity, EVM Opcode, and Precompiled contract.
Figure 13
Figure 13
Comparison between the use of memory in the classical and post-quantum scenarios when sending 5 tx/s.
Figure 14
Figure 14
Comparison between the average use of memory in the classical and post-quantum scenarios when sending 3, 5, and 10 tx/s.
Figure 15
Figure 15
Comparison between the use of CPU in the classical and post-quantum scenarios when sending 5 tx/s.
Figure 16
Figure 16
Comparison between the average use of CPU in the classical and post-quantum scenarios when sending 3, 5, and 10 tx/s.
See this image and copyright information in PMC

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