Haven Protocol will Rollback Chain to Block 886575 (June 27th)

Haven Protocol
3 min readJul 9, 2021

Do not conduct any on-chain transactions until further notice (Exchange transactions should be unaffected).

Beginning on June 22, 2021, malicious hackers attacked Haven Protocol, exploiting several related vulnerabilities. Following an extensive investigation, we conducted a wide-ranging review of the protocol and processes to ensure as smooth as possible recovery from the exploit.

We proposed a chain rollback to remove most of the inflation caused by specific exploits, particularly those with an unknown amount.

Our investigation determined that the optimal rollback point is block 886575 (June 27, 2021 at 22:21:08 UTC). We conducted a 24-hour ballot on July 8, 2021 to gain consensus from the Haven Protocol community, which voted 95% in favor of a rollback.

As a result, work has already started to include this rollback into the upcoming fork.

Details of the investigation and plan can be found here.

A rollback is where a blockchain is cut as part of a hard fork. Any transaction after the point where the chain is rolled back would be lost, and in effect reversed. It would be as if the ledger is rolled back in time.

While this is an extreme response that would typically impact a large number of users, in this case, we significantly mitigated the exploits by closing deposits and withdrawals on exchanges to minimize the movement of funds on the chain. Transactions within an exchange’s closed system are managed on each exchange’s database, not on the chain, so they should not be affected by the rollback. We are working with mining pools to distribute compensation from the Haven Protocol development fund to miners who support the network after block 886575.

The development team is now working on completing the patches for each exploit, designing an extension to the ringCT proofs and validation to strengthen the protocol’s transaction and conversion verification, test these new systems, and conduct third-party audits. The new codebase will be reviewed, vetted, and validated by experts with deep experience in cryptography and specialization in Monero before being deployed to mainnet.

The team is working as quickly as possible to complete this work. However, this process cannot be rushed, and time will be taken where needed to ensure it is robust and properly checked and tested. We will continue to share regular updates as this work progresses. When it is complete, we will share a date for the hard fork and rollback.

Once the fork and rollback are deployed, we will ask exchanges to update and re-open deposits and withdrawals.

The team and community recognize that many of the mitigation actions taken are reflective of centralized protocols. As outlined in The Path Ahead this past April, Haven Protocol’s goal has and continues to be to move towards an entirely decentralized future.

In the meantime, the team and community elected to make difficult decisions to secure the chain and protect new and old investors alike. These actions will make it possible to achieve Haven Protocol’s mission while giving community members the highest degree of confidence in the integrity of their holdings. The team continues to be greatly appreciative of the support and assistance received from the Haven Protocol community. We remain more committed than ever to building the future of private money.



Haven Protocol

Ecosystem of private stable assets. Based on Monero. The world's first private stablecoin xUSD is now live.