Date: May 15th, 2019
Hello BitcoinZ community! As you may know we have notified exchanges to keep withdrawals and deposits disabled until further notice and while we assessed the details of the ‘attack’. Please also keep in mind that security of the blockchain is always a priority, and further, if there are other known trusted persons in the community that can shed further on this issue, please respond here or let us know in Discord/Telegram.
What we know so far
Several persons identified anomalies in transactions beginning on or about May 12th to on or about May 13th 2019, at least as far as we can determine up to now. It appears to have been a Timewarp attack and/or a combination with overwhelming hashpower. This caused many block transactions to become orphaned, so it was a form of denial of service as well.
Guidance to Exchanges
Security is priority of course, but transactions from users of our network are also important. We will be notifying exchanges that any orphaned blocks/txns sent from their addresses should have already been released back to them, according to default settings in our core (currently zcash 2.0.3) the following are set:
-txexpirydelta Set the number of blocks after which a transaction that has not been mined will become invalid (min: 4, default: 20) -maxorphantx=<n> Keep at most <n> unconnectable transactions in memory (default: 100)
Exchanges should take note of the above settings so they can provide better customer service. From what we understand, they should have received the funds and will need to resend the transactions. Exchanges are in the best, if not the only position, to help their customers. BitcoinZ Community cannot assist those persons.
If you are a full node user and you sent transactions, this may also help you if you have stuck transactions.
First a reminder, we have a very important Proposal here: "Hydra" : A New Community Structure
Aside from that, the issues we’ve seen in the latest ‘attack’ need to also be addressed. We’ve been in communication with other projects/experts in the blockchain space so we’re devising the best approach to further secure from such attack. There are plenty of ideas being discussed. We take a careful approach to these types off issues and it takes a little bit of time.
A couple of other last minute notes. Please be aware that these people attacking the chain are more than likely lurking and watching our reactions, so some of the information we provide may be vague in nature, but please understand the consequence of not practicing careful delivery of messages to the community.
We will be advising exchanges on other details, at the same time we will be notifying them to require high confirmation count for deposits, and it is at their discretion to re-open deposits and withdrawals.
Thanks for everyones continued support, BitcoinZ onward! Please feel free to discuss or ask any questions.