According to blockchain data, miners in the network verified a block with four “shielded transaction outputs” at 1832666 block height. Twitter user ‘xenumonero’ was the first one to detect the blow-up in the size of the chain. The activity appeared to have maxed each 2 MB block every 75 seconds.
Interestingly, each of the transactions cost less than a cent. Jameson Lopp, the co-founder of Bitcoin security provider Casa, estimated that the attack is costing the scammer roughly $10 a day in transaction fees.
Who is to Blame?
While the motive behind the spamming activity is currently unknown, some users speculated it could be a pseudonymous Twitter user known as ‘fiatjaf,’ to be behind the attack. The user had previously tweeted that the “giant organizations” should attack Ethereum and Monero and crash these two networks if they want to ensure Bitcoin’s success. ‘fiatjaf,’ on the other hand, maintained that the spam was “certainly done by Monero enthusiasts.”
Both Monero and Zcash focus on privacy but follow different approaches to achieve the same. Monero, for one, leverages ring signatures and has a larger anonymity set. All of its transactions are private. Zcash uses zero-knowledge privacy protocol, a.k.a “zk-SNARKS” that enables users to remain anonymous. But unlike Monero, users on the Zcash network can choose between transparent and shielded transactions, allowing them to execute transparent transactions or make them completely private.
The latest spamming attack has caused the Zcash blockchain to bloat in size. This has resulted in the failure of nodes due to memory and performance issues with syncing this influx of shielded outputs, according to ‘xenumonero.’
Nick Bax, the head of research at Convex Labs, said that the spammer may have targeted Zcash to disrupt its nodes, drive investors to short its native token ZEC, or even discourage people from running nodes, thereby making network-level surveillance or even eclipse attacks more viable.
Bitcoin dev Peter Todd believes that Zcash and Monero are “particularly vulnerable to spam attacks because, unlike Bitcoin, they can’t do the pruning.” He said,
“All nodes need to maintain a list of spent coins indefinitely.”
ZEC’s price remained unfazed by the spamming on its blockchain and was currently trading at $56.23.
Earlier this year, the famed NSA whistleblower Edward Snowden revealed being the sixth participant, pseudonym “John Dobbertin,” that played a role in the creation of Zcash. During the revelation, Snowden confirmed that he received no compensation for the same and his involvement was just for the public interest.