Private transaction services represent a potentially complementary or orthogonal migration
strategy that specifically addresses short-range attacks during the window of vulnerability
between transaction broadcast and confirmation. These services, such as existing private
mempools like MARA’s Slipstream [MDH24], allow users to submit transactions directly to
trusted miners rather than broadcasting them publicly, preventing quantum adversaries
from observing and hijacking transactions before confirmation. While this approach doesn’t
eliminate the need for protocol-level quantum-resistant signature schemes, it could reduce,
but not eliminate19, risks during the transition period after such schemes are implemented.
It’s worth noting that even today, such services are contentious in the community as they are
often leveraged to include non-financial data storage transactions in the blockchain, and they
create a two-tier system for transaction broadcast.
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https://chaincode.com/bitcoin-post-quantum.pdfFrom the report, private transaction services like MARA's Slipstream let users send transactions directly to trusted miners instead of broadcasting them publicly. This helps prevent quantum adversaries from seeing and hijacking transactions before they're confirmed. But it doesn't replace the need for quantum-resistant signatures at the protocol level. However, during the transition period after implementing those signatures, this approach can reduce risks. The text also mentions that these services are contentious now because they're used for non-financial data storage and create a two-tier system. This is supposed to help against quantum attacks because a quantum computer could potentially steal the transaction details (like the signature) and create a conflicting transaction if they can see it in the mempool before confirmation.