Post-Quantum Blockchain

Baah Kusi
Coinmonks
Published in
3 min readJun 7, 2023

--

Photo by Anton Maksimov 5642.su on Unsplash

Summary

A post-quantum blockchain distinguishes itself by utilizing quantum-resistant cryptography instead of the currently standardized cryptographic schemes such as elliptic curves cryptography, RSA, and DSA.

Quantum-resistant cryptography ensures that the security of the blockchain cannot be compromised by future quantum computers. Although the arrival of such computers might be a decade away or more, it is imperative that prominent blockchains like Ethereum and Bitcoin begin considering the migration to quantum-safe cryptographic schemes.

One crucial factor to consider is that the process of migrating to quantum-resistant cryptography might span several years. Apart from the technical challenges associated with transitioning the network to a new cryptographic scheme, there are also logistical obstacles related to ensuring that all users switch over.

By proactively addressing these challenges, blockchain platforms can fortify their security and guarantee the integrity of transactions in the face of potential quantum threats.

How Quantum Computers Break Blockchain?

To underscore the gravity of the quantum threat, the National Institute of Standards and Technology (NIST) has taken proactive steps by initiating the standardization of post-quantum cryptography. NIST has called upon the cryptographic mathematics community to propose novel cryptographic schemes that can withstand quantum computer attacks. In fact, significant progress has been made, with NIST nearing the standardization of mathematically proven quantum-safe schemes.

This standardization process holds immense relevance for blockchain technology since it heavily relies on cryptography. For instance, popular blockchain platforms like Bitcoin and Ethereum currently employ Elliptic Curve Cryptography for crucial functions such as account and wallet creation, as well as transaction signing. The image below, extracted from a NIST paper, illustrates the cryptographic algorithms that are rendered insecure in a post-quantum world.

Since 2016, significant advancements have been made in the development of highly promising quantum-safe cryptographic algorithms, which are now nearing standardization. It is crucial that all blockchain networks intending to exist in the long term take immediate action to explore and experiment with these new algorithms, assessing their feasibility for network-wide adoption.

By embracing quantum-safe cryptographic schemes, blockchain platforms can ensure the long-term security and viability of their systems. Failure to address this critical concern now could lead to potential vulnerabilities in the future, jeopardizing the integrity and trustworthiness of decentralized transactions. The time to act is now, as we prepare for a quantum-resistant future.

How Migrating to New Cryptographic Schemes for Blockchain might play out.

In a post-quantum world, a critical consideration arises: the private keys corresponding to exposed public keys on the blockchain become common knowledge, assuming the presence of a sufficiently powerful quantum computer. Consequently, the existing private keys must be discarded, and new ones generated under a new cryptographic scheme. This process would typically occur within a designated migration period, during which users would manually create new private keys and associate them with their accounts.

To facilitate this transition, blockchains may need to implement flexible account access models that allow users to attach multiple private keys under different cryptographic schemes. Once the migration period concludes, the old cryptosystem, including all previous private keys, would no longer be valid on the network. However, it is crucial to acknowledge that delays could occur if not all users migrate within the specified timeframe.

The ultimate goal is to complete the migration before the advent of sufficiently powerful quantum computers. Smooth execution would ensure that users do not lose funds while upholding data integrity throughout the process.

--

--

Baah Kusi
Coinmonks

Blockchain Architect | Distributed Systems Engineer