(DailyHodl) Big Four accounting firm Deloitte says 4 million Bitcoin worth about $28.6 billion are especially vulnerable to attack from quantum computers.
BTC that’s held in “pay to public key” (p2pk) addresses are at a higher risk of quantum attack because their public keys – which could theoretically be used to derive a private key – are exposed on the ledger by default. These types of addresses were utilized in the early days of Bitcoin, before a new standard was implemented.
That new standard is called p2pkh (pay to a public key hash), and only exposes public keys the moment any amount of BTC is sent from an address. The analysis indicates that BTC that has been sent to a new, modern p2pkh address with zero outgoing transactions is inherently far less susceptible to attack.
Deloitte also highlights ongoing attempts to create new methods of cryptography that are resistant to quantum attack and could one day be integrated into the leading crypto assets. “The only solution in this case is to transition to a new type of cryptography called ‘post-quantum cryptography’, which is considered to be inherently resistant to quantum attacks. These types of algorithms present other challenges to the usability of blockchains and are being investigated by cryptographers around the world.”