BLAKE2b Chain Listing Hesitation Amid Replay Attack Concerns

The listing of the BLAKE2b-based blockchain, which forked from Bitcoin (BTC), has become contentious due to concerns over transaction replay attacks and chain integration. Exchanges and wallets face the challenge of accurately distinguishing between the two chains.

David Schwartz, Ripple's former CTO, reportedly cited technical safety issues as a reason why exchanges that supported past Bitcoin forks have been hesitant to support the BLAKE2b-based chain. U.Today reported on Schwartz's comments, though his original X post could not be verified.

The BLAKE2b chain replaces Bitcoin's SHA-256 proof-of-work with BLAKE2b, a change implemented at block height 961640 on August 30, 2026. The official FAQ states that pre-fork transaction history and keys remain intact, but post-fork validation uses the new proof-of-work method, treating it as a separate chain.

Key concerns for exchanges include the risk of shared transaction history between chains, where a transaction signed on one chain could be processed on another, leading to unintended fund movement. A replay attack occurs when a valid transaction from one chain is repeatedly submitted to another. To prevent this, exchanges may temporarily halt deposits and withdrawals, segregate assets by chain, and verify that wallets and nodes correctly distinguish between chains.

The official FAQ notes that standard signatures can be replicated across chains, though the optional 'SIGHASH_UNIFIED' signature method offers limited protection for non-supporting chains. Exchanges are advised to clearly state which chain they recognize and suspend deposits/withdrawals if necessary.

As of September 8, no listing was found on Coinbase ($COIN), with major exchanges also not confirming support. However, this does not necessarily indicate formal rejection; Coinbase reviews technical security and regulatory requirements for assets, noting that new asset types may require additional integration work.

Market reactions are mixed: some community members argue that listings on Coinbase or Kraken could signal asset credibility, while others express concerns about hash rate and chain stability. These views reflect social media and community sentiment, not official positions from exchanges or development teams.

The hesitation in listing is unclear whether it stems from simple disinterest or thorough verification for replay attack prevention and wallet/node integration. Schwartz's comments were interpreted as highlighting technical possibilities rather than an official reason from exchanges.