Bitcoin developers are increasingly frustrated with a griefing attack on testnet that has disrupted its operations, interrupted node syncing and created thousands of new blocks per hour.

Jameson Lopp, cofounder and chief technology officer of Bitcoin security provider Casa, claimed responsibility for the attack.

“My griefing attack on Bitcoin testnet has resulted in over 165,000 blocks (3 years worth) generated in the past week,” said Lopp on decentralized social media platform Nostr. 

“It cost me approximately a dollar worth of electricity,” he added, in response to a user who rhetorically questioned if it was “worth it.”

A griefing attack involves intentionally spamming transactions on the network, increasing its workload, and generally throwing it into a state of disarray, while providing no real economic incentive to the attacker.

Lopp, who is a longtime Bitcoin advocate, suggested that his actions were meant to be beneficial stress test, and something that actually takes place naturally on the testnet several times per year.

“I’ll be publishing an essay next weekend with full details, but it should come as no surprise to anyone who read my email to the development mailing list several weeks ago,” Lopp said in response to one disgruntled Bitcoin developer on X.

Improving Bitcoin’s Testnet?

In that email to the Bitcoin developer mailing list on April 1, Lopp sought feedback on some potential changes to the testnet, including a reset of the network itself, fixing the difficulty reset bug, or simply deprecating the testnet itself in favor of Signet — a proposed new test network that would use digital signatures to validate blocks instead of a proof-of-work system. 

“Testnet3 has been running for 13 years. It’s on block 2.5 million something and the block reward is down to ~0.014 TBTC, so mining is not doing a great job at distributing testnet coins any more,” Lopp said.

He also raised issues with the fact that testnet coins are now being actively bought and sold, breaking the fundamental principle of testnet coins having no value.

Most developers were in favor of maintaining the testnet as is, keeping it as close to the Bitcoin mainnet as possible, but some entertained the idea of fixing the difficulty adjustment to discourage scammers from building on Bitcoin testnets. 

“Unfortunately, the current form of Testnet is doomed to have value, just like BTC. Its scarcity makes it a valuable asset. And no reset will change that. It will only result in repeated resets, multiple versions of testnet, and people never learning,” wrote Bitcoin developer “emsit” in the email chain.

Another developer, who goes by the pseudonym “coinableS,” said that a testnet reset would require hashpower behind it, which may pose a problem if there are entities currently benefiting from the existing chain. 

“The last reset was so long ago the community was much tighter-knit and shared a similar ethos making a reset deploy rather trivial to a point of near centralization, today there are a lot more parties involved that would need to cooperate on a reset,” said the developer.

Meanwhile, Bitcoin developer Matt Corallo, who has also been an active voice in Bitcoin’s mining centralization issues, suggested that the testnet had run its course, now that there is a market for testnet coins.

“It has always been very clearly communicated that if testnet starts being valued or traded it will be reset. There’s some legitimate debate over parameters in a reset here, but in the meantime testnet3 has ceased to serve its intended purpose as a valueless test platform,” said Corallo in the email chain.