Network Privacy in Blockchains

2018.06.27 13:00-14:00 - Isis Agora Lovecruft - Part 1

This workshop about the privacy in propagation protocol within blockchain networks and de-anonymization of transactions.

List of papers on blockchain network privacy: https://github.com/isislovecruft/library–/tree/master/anonymity%20&%20circumvention/bitcoin

(Go up the path in the repo for more exciting papers)

Separate groups discussion on the network anonymization protocols (Some are fictional at this point):

  • Dandelion
    • MimbleWimble / Grin
  • Whisper Protocol (Ethereum)
  • Tumblers
  • Noise networks
  • Use Tor / Use Signal
  • Use Wireguard
  • Broadcasted Encryption
  • Randomized Transaction Handling
  • Kovri - used in Monero. Onion routing style like tor but different approach (DHT Node discovery, Uni-directional routing (closer to free route mixnets), designed for low latency networks, probably works well for P2P but may not work well for client-server architecture).
  • Mixnets

Each group posted their proposals on the window and the rest put star stickers on their preferred proposals: Proposals Scored by stars with a view of Montreal under construction

Top Rated:

  • Kovri
  • Dandelion

Research Ideas:

  • Node Random Path selection

2018.06.27 14:10-15:10 - Isis Agora Lovecruft - Part 2

… [missed the beginning of the discussion]

Discussion:

  • Discussion regarding how Dandelion Protocol works, One example: Grin Spec
  • Timing attacks by an entity that runs multiple (many) nodes in the network
  • Issue with being always online on the protocols like Signal
  • Mix networks High latency privacy network, pool up transactions to achieve anonymity
    • Chose a route in advance by the client
    • None of the nodes have access to where the transaction comes from and leaves to
    • Not good when nodes are not consistently online, need more stable networks
    • Cascade mixing
      • At least requires one honest node on a path for everyone to use this one path
    • Traffic Analysis Resistant Messaging: katzenpost
    • Originally designed for e-voting and e-mail
    • If used in Blockchain networks, it can’t be used for miner nodes, as the high latency might lead to network forks and higher rate for orphaned blocks.
  • Some discussion on possible attacks such as eclipse attack, sybil attack, 51% attack.