Ledger CTO Charles Guillemet has highlighted the potential risk quantum computing poses to cryptocurrency security, particularly through its ability to break Elliptic Curve Cryptography. This cryptographic method is crucial for securing blockchain transactions via public and private keys. Although quantum computers capable of such feats do not yet exist, Guillemet stresses the importance of preparing for this eventuality. Guillemet notes that public keys, often exposed during transactions, could be vulnerable if quantum computers advance sufficiently. He emphasizes the need for post-quantum cryptography, which offers quantum-resistant signature schemes, to safeguard against future threats. Ledger is actively experimenting with these cryptographic solutions, despite challenges like RAM pressure and compute costs. The potential risk extends to approximately seven million Bitcoin, including those attributed to Satoshi Nakamoto, due to early transaction methods that exposed public keys. Meanwhile, Ethereum co-founder Vitalik Buterin is also working on securing the Ethereum blockchain against quantum threats, underscoring the industry's proactive stance on this issue.