Cox Invites Developers to Assist with BCH Code Development & Review

There have been Bitcoin Cash (BCH) developer discussions ahead of the scheduled upgrade in May. In a recent video meeting, they acknowledged the need to determine the amount of BCH stuck in P2SH SegWit addresses. Jason Cox also extended an open invitation for assistance with BCH code development and review.

David R Allen moderated the BCH developer meeting, which consisted of Bitcoin Unlimited developer Andrea Suisani, Bitcoin ABC developers Antony Zegers and Jason B. Cox, Bitcoin ABC Amaury Sechet, CTO Emil Oldenburg, BCH developer Mark Lundeberg, and Openbazaar developer Chris Pacia.

The meeting started with conversations on BIP 62. Zegers noted that several BCH users failed to retrieve their funds because they are transferring BCH to BTC SegWit P2SH addresses. Cox then inquired if they can determine the extent of the issue. Oldenburg responded by suggesting indexing every SegWit address, then checking the UTXOs.

Lunderberg recommended a way to address third-party malleability by utilizing the clean stack rule to Pay-to-Script-Hash multisig and Pay-to-Public-Key-Hash. With that, other scripts need to check itself manually via OP_DEPTH. He added that his solution would necessitate another hard fork in addition to the May 2019 upgrade.

The developers concluded that they have to identify how much coins are locked in P2SH SegWit addresses before moving on BIP 62.

Lunderberg noted that after the hard fork in August 2017, there were in the ballpark of ten transactions which were under 100 bytes. He suggested relaxing it to 64 bytes as a 100-byte limit could impact certain transactions.

According to Cox, reducing the byte transaction size limit is easier than raising it. Suisani added that increasing the byte transaction size limit need to be implemented through a hard fork. The developer volunteered to lead the second agenda by keeping a communication stream among developers.

Regarding Schnorr signatures, Sechet said Schnorr possesses cost benefits because of batch validation. He also emphasized that it is better for the Bitcoin network and will help with user privacy. The Bitcoin ABC lead developer warned that the code needs to be reviewed and implemented carefully to prevent the network from being susceptible to side-channel attacks through the cache hierarchy and the branch predictor of the CPU.

Lunderberg agreed to review Sechet’s code within one and a half month. Cox is inviting developers and cryptographers to help in the development and review of the BCH code.

In response, Suisani said he would ask other Bitcoin Unlimited developers if they want to work on the old opcodes. He explained that these developers were the logical option since they had included Nchain implementation in their SV client.

Per Oldenburg, the 25 unconfirmed transaction chain limit affects different protocols and requires fixing. He added that was presently working on its on-chain dice game like Satoshidice. The firm reached out to Oldenburg for some closing thoughts.’s CTO was positive on the developers meeting, particularly since the “limitation of unconfirmed chained transactions will be removed long term.”