Ledger CTO Warns of Migration Risks for Multi-Signature Wallets with Compromised Coldcard Seeds
Ledger CTO Charles Guillemet pointed out that if a Bitcoin multi-signature wallet can be fully spent using compromised seeds (for example, two of three Coldcard seeds are weak), it is in a critical state.
He stated that if using P2WSH or P2SH-P2WSH, the spending script will not be on-chain before the first spend, providing some protection, as the attacker may only have the compromised keys and might still lack the script; however, the script is not secret and may already exist in wallet databases, backups, and other systems, so it should be migrated to a new secure setup as soon as possible.
Migration transactions will reveal the script in the mempool, and if the attacker already has enough keys and the script, they can initiate conflicting transactions; to reduce risk, avoid broadcasting through the public mempool and instead use trusted private transaction relays to submit directly to miners, such as MARA's Slipstream.
Source: Public Information
ABAB AI Insight
As the security head at Ledger, Charles Guillemet continues to provide technical guidance following the Coldcard seed entropy issue, emphasizing that while multi-signature enhances security, migration itself becomes a new attack window when some keys are compromised.
In terms of capital and security pathways, it is advised to bypass the public mempool through private relays, motivated by the need to reduce the exposure time window of scripts and protect users during the asset migration process after vulnerabilities are disclosed.
This is analogous to the urgent migration wave following past hardware wallet vulnerabilities and discussions on Taproot and script privacy, currently in a "post-vulnerability migration battlefield" practice phase.
Essentially, this is a technical substitution: when seed generation flaws are exposed, multi-signature shifts from static protection to dynamic migration games, with private relays serving as temporary structural tools to reduce the risk of conflicting transactions.
ABAB News · Cognitive Law
Migration itself may become an attack window
Exposure of the script is the last layer of protection
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