BCH Devs Discuss Securing Instant Transactions With the Avalanche Protocol

Over the last couple of weeks, the Bitcoin Cash (BCH) community has been talking fervently about zero-confirmation transactions and a new pre-consensus mechanism called Avalanche. On Monday, Openbazaar developer Chris Pacia published a comprehensive description of the pre-consensus protocol that could theoretically bolster secure zero-confirmation BCH transactions.

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A Pre-Consensus Concept Called Avalanche Could Bolster Zeroconf BCH Transactions

Since the hard fork in November, BCH developers have been exploring an idea called Avalanche, a concept that could hypothetically add a double-spend protection mechanism to zero-confirmation transactions. These types of instant transactions are broadcast to the network before they are confirmed and some people believe there is still an open double-spend attack vector for unconfirmed transactions. Essentially, Chris Pacia’s recent post, called “Making Zeroconf Secure”, describes how the Avalanche protocol could protect unconfirmed transactions by having a group of participating nodes come to pre-consensus.

“Avalanche is a new consensus protocol that was first introduced earlier this year — It provides a novel way for nodes on a network to choose between two conflicting transactions and come to a consensus about which one should be included in the next block,” explained Pacia.

The Openbazaar developer continued:

Using Avalanche in Bitcoin Cash for miner coordination provides a very elegant, decentralized coordination mechanism that can potentially prevent miners from accepting double spend bribes and when combined with double spend notifications, make zeroconf transactions very secure.

Proof-of-Work: The Anti-Sybil Mechanism

The developer further explained that each node participating in the pre-consensus method will query or poll each other in order to validate the transaction. However, rather than using nodes that can be easily ‘sybiled,’ the Avalanche system would use the pools of BCH miners already securing the network. In a sybil attack, nodes in a network are easily spoofed and the software is hijacked by a variety of manipulative phony nodes.

“Proof-of-work is used as the anti-sybil mechanism. The miners of the last 100 blocks form the consensus group and participate in Avalanche. This is a rolling membership group. Each new block a new miner is added to the group and the miner who mined block n-100 gets booted,” Pacia detailed in his post.

The Avalanche discussion heated up even more so when a video demonstration and a descriptive editorial was published showing an alleged double-spend vector on the BSV network. A BCH proponent named Reizu confessed, “I’ve done many double-spends on the Bitcoin SV network.” Pacia believes the BCH network, on the other hand, is very close to making zero confirmation transactions secure. The Openbazaar developer believes there’s a better solution to the problem than orphaning blocks and suing people when things go wrong.

“The difference in the quality of research, proposal, and implementation between BCH and BSV really isn’t even comparable,” Pacia concluded.

What do you think about the Avalanche protocol and pre-consensus methods? Let us know what you think in the comments section below.

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