Stacks Tests Post-Quantum Signing in Mainnet sBTC Transfer

Stacks completed a mainnet sBTC vault withdrawal using a Lamport one-time signature to authorize release, testing post-quantum signing in the vault flow.

The test did not upgrade ordinary sBTC wallets or the Bitcoin backing the token.

The test touches a broader design issue for Bitcoin. Bitcoin uses ECDSA and Schnorr signatures, which a sufficiently powerful quantum computer could threaten. Post-quantum alternatives may require larger signatures, adding transaction data.

Stacks co-founder Muneeb Ali has estimated that larger signatures could cut Bitcoin block capacity by as much as 10-fold, a tradeoff described in Ali’s estimate of the capacity impact.