Forwardable Peerswap Incentives, And Closing Surreptitious Communications Tunnels

In the realm of cryptocurrency transactions, particularly involving the Lightning Network, there are specific pieces of data that cannot be completely obscured by forwarders during peerswaps. These include the transaction amount and the timelock duration for the Spilman channel, which facilitates the "onchain" hop. The transaction amount, compared to node identifiers, provides significant information potentially revealing the identity of the Initiator due to its high bit availability.

To mitigate the risk of identity exposure through these data points, a strategy can be implemented where onchain transaction amounts are standardized. A limited set of predefined amounts—10 BTC, 1.0 BTC, 0.1 BTC, 0.01 BTC, 0.001 BTC, and 0.0001 BTC—can be used. This approach helps in masking the exact transaction details, therefore reducing the bits of information available for potential identity inference.

For timelocks, it is proposed to standardize the duration to extend +2016 blocks from the current block height. Additionally, a tolerance range from +2012 to +2016 blocks should be maintained to account for any new blocks that may be added during the initial negotiation phase. This standardization aids in further obfuscating the transaction details from malicious entities aiming to track transaction specifics or user identities.

Regarding onchain fee rates, another potential leakage point of sensitive information, it is suggested that these could be deferred or omitted from the protocol. By utilizing a zero-feerate transaction for the initial in-Spilman Hash Time Locked Contract (HTLC) offer, followed by possible adjustments through child transactions by either the Acceptor or the Initiator as necessary, the need to communicate feerates directly in the transaction protocol can be effectively eliminated. This step ensures that fee rates do not become a conduit for hidden data exchange that could compromise user anonymity.