bitcoin-dev
Trivial QC signatures with clean upgrade path
Posted on: January 1, 2025 08:37 UTC
In an engaging discussion on enhancing the security of wallets against potential quantum computing threats, Matt Corallo introduces a concept centered on the use of QC-secure commitments within wallet construction.
He references the innovative approach of Guy Fawkes signatures, as initially outlined by Tim Ruffing, to augment both regular and alternative spending conditions. This method involves incorporating a specific scriptpath that integrates a key with a cryptographic check sequence, which effectively serves as a backup mechanism for keypath spending. The proposed technique, while promising in terms of preemptive security measures against quantum computing capabilities, carries certain drawbacks that merit attention.
One significant concern highlighted is the necessity of a blockchain fork to implement this security feature, should the threat of quantum computers materialize. This requirement signals potential challenges in terms of network consensus and compatibility, particularly affecting nodes that have been pruned and are then forced to re-download and re-scan historical blocks post-activation of such a fork. Another notable trade-off discussed is the delay in the spending of taproot outputs in the wake of a quantum computing crisis, estimated at a minimum of 100 blocks. Despite these challenges, the advantage of this approach lies in its avoidance of immediate specification work or consensus changes, appealing to developers wary of the complexities associated with post-quantum cryptosystems.
For further details, the original discussions and expansion on this topic can be explored through the provided links: link 1 and link 2. These resources offer in-depth insights into the technical underpinnings and implications of adopting Guy Fawkes signatures within the context of taproot outputs and quantum-resistant cryptographic strategies.