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Zcash Bug Prevents Private Transactions Soon After Launch

Last Updated March 4, 2021 4:52 PM
Andrew Quentson
Last Updated March 4, 2021 4:52 PM

Just after Zcash launched, the anonymous new digital currency that has taken the crypto world by storm, a bug  was found that apparently prevents private transactions from being mined.


Zcash’s official website states :

“There is one known bug, which causes private transactions (those in which all of the inputs and outputs are shielded addresses) to not get mined. We’re going to release v1.0.1 shortly to fix it.”


The Zcash Mining Pool  currently has a big red banner which states: “Because of a critical Zcash wallet bug we are unable to send any payments to z addresses at the moment. Please only use t addresses for now. We will resume payments to z addresses once the Zcash wallet bug has been resolved!”

Zcash allows for two type of addresses: z-addr transactions, which are fully private, and t-addr transactions, which are transparent, like bitcoin’s transactions. Z-addr transactions are meant to look as in the image below:

A Theoretical Zcash Private Transaction
A Theoretical Zcash Private Transaction

The public address is meant to be hashed for both sender and receiver with no zec amount shown, making it impossible to gather any information regarding the transaction. From some preliminary research, however, we were unable to find a z-add transaction on the live main-net block explorer. It may well be the case, therefore, that no such transaction has ever occurred, yet.

If so, then private Zcash has not, practically, launched, as the technology is not currently operating in a live environment. It has not yet been proven, therefore, that such transactions can occur in the manner described.

The technology behind Zcash, zero-knowledge Succinct Non-interactive Arguments of Knowledge (zk-SNARKs) or zero knowledge proofs, is a very recent invention. Although Zcash’s development team is impeccable with numerous hackers, scientists and researchers from John Hopkins University, Tel Aviv University and MIT, including a number of worldwide renown cryptographic researchers, Zcash’s promise of absolute privacy were previously made by Bitcoin and Monero.

As such, we will have to wait until we can see a hash on hash transaction without revealing any other information in a live environment, before we can be in anyway confident of Zcash’s strong privacy guarantees.

Images from Shutterstock and Zcash.