Privately sending payments while offline with BOLT12

The concept discussed involves a novel approach to facilitating payments through encrypted data transfer using onion-message paths. This method allows the payer to securely send necessary messages, such as update_add_htlc, over an onion-message path rather than through the standard BOLT8 tunnel. This process is particularly useful when the mobile phone of the payer serves as the client for a Lightning Service Provider (LSP) or when interacting with a high-uptime home node.

The proposal outlines two key standards aimed at enhancing the efficiency and security of transactions. The first standard suggests a mechanism for remote control communication with a high-uptime home node via BOLT8, ensuring that users can manage their transactions remotely without compromising on security or functionality. The second standard focuses on enabling a high-uptime payee to create a "BOLT8 tunnel" over onion messages. This innovative approach facilitates the payee's assistance in helping the payer contact either its LSP or its high-uptime home node. Subsequently, the LSP or the high-uptime home node converts the received onion messages into BOLT8 messages, treating them as if they were transmitted over a BOLT8 tunnel.

This methodology significantly broadens the applicability of the system, accommodating both scenarios where the payer operates through a remote-controlled home node and where the payer uses a mobile phone connected to an LSP. By implementing these standards, the transaction process becomes more versatile, secure, and user-friendly, catering to a wider range of payment scenarios and user needs.