At press time, Zcash miners had verified a block with four shielded transaction outputs at a block height of 1832666, according to the blockchain’s explorer tool.
Zcash spammer’s motive still unclear
Twitter user xenumonero first pointed out the spammer’s activity:
At press time, at least two out of five blocks had been maximally spammed with shielded transaction outputs, having sizes close to the two-megabyte limit. The size of the most recent block was roughly 1.4 megabytes.
While the motive of the attack has not yet been determined, bax1337 of Convex Labs believes that the goal is to bring Zcash into disrepute through nodes failing because of memory, performance, and synchronization issues. Additionally, potential node operators could be discouraged from participating in the network, making the blockchain susceptible to surveillance or so-called Eclipse attacks.
Eclipse attacks occur when a hacker fools a network node by creating an artificial environment around it to make it receive bogus transaction confirmations, amongst other things. The success of an Eclipse attack depends very much on the structure of the underlying blockchain, and often the inherent blockchain structure is enough to frustrate these attacks.
Monero is another privacy-focused crypto project that uses so-called ring signatures to obscure the identities of the sender and receiver in a transaction. Ring signatures combine a sender’s signature or permission for a transaction with other signatures. This combination makes it difficult to determine which signature belongs to the sender.
Zcash, on the other hand, uses a cryptographic proof called Zero-Knowledge Succinct Non-Interactive Argument of Knowledge, or zk-SNARK, for its shielded transactions. It allows a transacting party, for example, to convince a verifier that a number exists for a given cryptographic hash without letting on what that number is.
Zcash was founded by a group of scientists who forked the Bitcoin software to create a cryptocurrency called Zerocash. The scientists founded Zerocoin in 2015, later becoming the Electric Coin Company.
Is Zcash secure?
According to the Zcash blog, both Electric Coin and the Zcash Foundation conduct regular audits to assess the security of the blockchain. The blockchain is also routinely upgraded to accommodate present and future use cases.