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As debate grows over whether quantum computing could one day crack today’s cryptography, analysts are drawing sharper distinctions between how Bitcoin (BTC) and Ethereum (ETH) might fare under a credible quantum threat—arguing that structural design choices could make Ethereum faster to expose, even if the danger remains largely theoretical for now.
The core issue is what security researchers call CRQC—cryptographically relevant quantum computers capable of breaking widely used public-key schemes. While most experts still place CRQC years away, the discussion is increasingly shifting from “can it happen” to “where would it hit first,” as investors and protocol developers weigh long-term resiliency alongside present-day cyber risks.
Public key exposure: why Ethereum may be visible sooner
One of the biggest differences between the two networks lies in how and when public keys become visible. Bitcoin commonly relies on address formats such as ‘P2PKH’, where users publish a hash of the public key rather than the public key itself. In practice, that means a Bitcoin public key often stays hidden until coins are actually spent—making it harder for an attacker to pre-select targets at scale before on-chain activity occurs.
Ethereum, by contrast, uses an account-based model. Once an account has broadcast a transaction, its public key can be inferred from the signature and is widely treated as effectively exposed thereafter. If quantum decryption becomes feasible, that persistent exposure could give attackers a longer runway to catalogue and prioritize targets, analysts argue.
Broader cryptographic footprint: ECDSA plus BLS
Differences also emerge in the signature systems each ecosystem depends on. Bitcoin primarily uses ‘ECDSA’ for transaction signatures. Ethereum uses ECDSA for user accounts as well, but also relies on ‘BLS’ signatures for core proof-of-stake functions tied to validators and staking operations.
Both ECDSA and BLS are considered vulnerable in principle to Shor’s algorithm on sufficiently powerful quantum hardware. However, observers note that BLS is linked to large swaths of Ethereum’s infrastructure: validator keys, staking-related permissions, and critical operational roles. That connection leads some researchers to characterize Ethereum’s potential ‘attack surface’ as broader because multiple cryptographic systems would need to be migrated and secured in parallel.