Sergei Tikhomirov and Lightning privacy

Postdoc Researcher Sergei joins Murch and Jonas to talk about channel balance probing in Lightning, privacy concerns in general, and the importance of researcher-developer collaboration.

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We discuss:

  • Sergei’s background (1:50)
  • Lightning basics (2:50)
  • Why LN payments fail (3:40)
  • Why privacy is important (5:30)
  • Privacy potential of Lightning vs L1 Bitcoin (6:40)
  • How probing works (8:40)
  • Why is balance discovery bad? (11:30)
  • Persistent identities in Lightning (13:00)
  • Multi-vector security model and trade-offs (17:45)
  • The danger of overestimating Bitcoin’s privacy (21:00)
  • Lightning integrations and walled gardens (22:00)
  • Lightning Service Providers and LN’s centralized topology (23:05)
  • LNBIG booth in El Salvador (25:30)
  • Potential oligopoly of large nodes (27:15)
  • Probing parallel channels (28:30)
  • Combining probing with jamming (33:00)
  • The limit on in-flight payments (36:00)
  • Bad and good probing (41:20)
  • Countermeasures and reputation (44:00)
  • Hub-and-spoke terminology and aviation analogy (49:00)
  • Doing research in Bitcoin and Lightning (53:10)
  • Why Bitcoin is unique (55:10)
  • Researcher-developer collaboration (58:00)

Related research:

Thanks to Justin for the sound engineering.