Performance Goals and the Role of Tachyon
The reason for building all this is arithmetic.
Mastercard and Visa process more than 50,000 transactions per second, and the team calls that number “their floor, not their target.” Zcash’s current cryptography would require a node to receive and verify more than 500 megabytes of data every second to keep up, because every private transaction carries a proof, and the proofs are big.
This is about a full DVD of data arriving every ten seconds, continuously, and no current Zcash software runs anywhere near that. But the missing piece is the reason each bottleneck exists.
Bowe’s Tachyon Project is addressing this by working on recursive proofs, in which one proof attests to the validity of thousands of others, dramatically reducing the amount of data that must be verified in the consensus.
Under Tachyon, a node verifies a single proof instead of thousands, which the team says reduces the consensus data requirement from 100 megabytes per second to 500 megabytes, a level they say is technically achievable with careful engineering.
Wallet Bottlenecks and Valar PIR Solution
Wallets have a different problem. Because Zcash hides who a transaction is for, a wallet cannot ask a server which transactions belong to it without revealing itself. It downloads everything and tries each one, which is why the wallet software maxes out at about one transaction per second.
