Ethereum developers propose upgrading the deposit contract to support larger validator keys and quantum-resistant BLS signature retirement.
Tech & Launches ·
Ethereum developers submitted a draft proposal Monday to overhaul the validator deposit contract, enabling support for cryptographic keys up to 8,192 bytes and introducing an irreversible retirement mode for the current BLS signature scheme. The existing contract hardcodes BLS12-381 parameters, limiting public keys to 48 bytes—insufficient for post-quantum cryptography—and the redesigned contract accepts variable-length credentials while allowing deposits to specify which signing scheme they employ. Once the system transitions to retirement mode, no mechanism can re-enable BLS onboarding.
The underlying post-quantum cryptography remains unsettled. Draft author Thomas Coratger noted that networks are "heavily leaning" toward hash-based signatures standardized by NIST, which reach approximately 8 kilobytes per signature—matching the contract's ceiling—though compact variants carry a counter that risks exposing private keys if reused. The Ethereum Foundation assembled a dedicated team last year to coordinate the transition, while a quantum security firm's May analysis suggested a better-than-even chance of machines capable of breaking elliptic curve signatures by 2033.
The proposal awaits editor review with multiple critical details unresolved: contract address, deployment code, and activation timestamps remain undecided. Implementation would require a coordinated fork across both execution and consensus layers. The specification of which post-quantum scheme validators will actually use falls to future proposals.