How Quantum Computing Threatens Cryptocurrency

Current mainstream cryptocurrencies, such as Bitcoin and Ethereum, primarily rely on hash functions (such as SHA-256) and public key cryptography (such as ECDSA elliptic curve signatures) to ensure security. However, the development of quantum computing poses a serious threat to these two cornerstones.

First, Shor's algorithm in quantum computing can efficiently break elliptic curve encryption, directly deriving the private key from the public key. This means that once the public key is exposed, attackers can forge transactions and steal assets. In on-chain historical data like Bitcoin, many early accounts' public keys have already been made public, and once quantum computing matures, these assets can easily be stolen.

Second, Grover's algorithm can enhance the efficiency of brute-forcing hash functions to the square root level of classical computers. Although the direct threat to standard hash functions like SHA-256 is limited in the short term, in scenarios such as mining competition and attacking old transaction data, quantum miners will gain a significant advantage.

Overall, the threats posed by quantum computing to cryptocurrency are mainly reflected in the destruction of transaction signatures, unfair competition in mining, and the potential for on-chain data tampering.

Currently, although truly threatening quantum computers have not yet emerged, major blockchain projects around the world are actively researching quantum-resistant cryptographic technologies, such as lattice-based cryptography and hash signatures, to proactively address future challenges.

In short, quantum computing is a major test that the cryptocurrency sector cannot avoid in the future. Those who can plan ahead will be able to survive in the crisis.