Fidelity Digital Assets Report on Quantum Threat to Bitcoin ECDSA and Schnorr Signatures
Fidelity report by Daniel Gray reviews CRQC risks to Bitcoin signatures and the SHRINCS BIP soft-fork proposal with noted throughput trade-offs.
Fidelity Digital Assets published a report by senior research analyst Daniel Gray that examines the threat cryptographically relevant quantum computers pose to Bitcoin's ECDSA and Schnorr signatures.
The report states that a soft fork would be required to activate any new signature scheme and identifies the increase in signature size as the central challenge because larger signatures reduce the number of transactions per block.
Throughput trade-offs
The SHRINCS BIP from Blockstream combines quantum-resistant schemes, one for efficiency and one for recovery, to address the size constraint.
Fidelity notes that Bitcoin's currently near-empty mempool may limit near-term throughput effects, though exact impacts under different mempool conditions remain unknown.
Open questions
No timeline is given for the arrival of cryptographically relevant quantum computers, and the report leaves consensus process and activation details unspecified.