Published on: 2020-04-02T17:42:06+00:00
In discussions surrounding payment systems, particularly in the context of anonymous multi-hop locks, participants have emphasized the importance of privacy and security. They have analyzed potential vulnerabilities, proposed modifications to existing protocols, and explored different approaches to ensure the confidentiality and integrity of transactions.One approach discussed is the use of route blinding to enhance wallet users' privacy. This proposal aims to simplify the scheme by using the same secrets derivation as Sphinx. However, certain aspects of the proposal, such as invoice fields and encrypted blob format, are intentionally left vague to allow for further development based on early prototypes. The goal of the payment secret is to prevent the next-to-last node from discovering it to avoid probing. While some participants question the effectiveness of using blinding to replace the payment secret, others highlight that the secrets established through anonymous multi-hop locks are between the sender and each hop, while in route blinding, the secrets added are between the recipient and the hops. There is uncertainty about whether the recipient can safely contribute to these secrets, but a solution is hoped to be found in the future.Rusty Russell has been exploring a scheme proposed by t-bast for blinded paths that can simplify the rendezvous routing process. Rendezvous routing typically requires single-use, which makes it unsuitable for static and reusable offers. In this scheme, Alice presents Mallory with a path (Carol, Bob, Alice) where Mallory can create an obscured onion that can be unobscured by various nodes, forcing Mallory to use the entire path. To establish shared secrets with Bob and Carol, Alice provides Mallory with two ECDH blobs to place inside the per-hop payload. However, Bob needs the secret before he can unwrap the onion, so the ECDH blob for the next peer needs to be sent alongside the onion itself. Different proposals are made regarding how to encrypt the payload, including using XOR with the secret or encrypting a general payload. The proposed solution introduces new invoice fields and additional fields such as 'blinding' and the 'tlv_payload' field 'encblob'. It also addresses error handling and obfuscation.ZmnSCPxj suggests reusing the secret for each hop instead of using a payment secret, as the blinding scalar for path decorrelation serves the same purpose. It is also proposed that the first 32 bytes of the payment secret could be used for ECDH to decrypt enc1. Notably, the scheme does not include a channel_update.In summary, discussions have emphasized the importance of privacy and security in payment systems. Proposed solutions include route blinding to enhance wallet users' privacy and a scheme for blinded paths to simplify rendezvous routing. Shared secrets and ECDH blobs are used to establish communication between nodes. Reusing the secret for each hop and using a portion of the payment secret for decryption are also suggested. The proposed scheme does not include a channel_update. Further research and analysis are needed to fully understand the implications and effectiveness of these proposals.
Updated on: 2023-07-31T22:44:23.143200+00:00