Grin Token 51% Attack

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Grin Token

The Grin token blockchain was 51% attacked after a mining pool managed to gain control of the majority of the hashing power. Transactions were reorganized and it's not clear if any funds were lost.

This is a global/international case not involving a specific country.

About Grin Token

"Electronic transactions for all. Without censorship or restrictions." "Designed for the decades to come, not just for tomorrow. To be used by anyone, anywhere." "Grin was launched on January 15th, 2019." "It's very young and experimental. Use at your own risk!" "Grin, which was the first cryptocurrency to test privacy protocol MimbleWimble and drew an estimated $100 million in venture capital to mine it, was once called “Bitcoin 2.0.”"

"The most recent attack on a proof-of-work cryptocurrency dates back to November 2020. Grin, another privacy coin that suffered a 51% attack on its blockchain network. The Grin team built its token on the Mimblewimble protocol."

"According to a Nov. 7 tweet from crypto mining group 2Miners, an unknown group accumulated 57.4% of the total hash power of the Grin (GRIN) network on Saturday evening. 2Miners only had control of 19.1% of GRIN’s hash power, while sparkpool miners came in third at 18.9%."

"Grin Network Is Under the 51% Attack!" "Payouts are stopped. Please mine at your own risk only because the new blocks could be rejected."

“Important notice,” the web portal’s warning reads. “The Grin network hashrate has increased considerably over a short period of time. Notably, this coincides with the Nicehash rate doubling in this time with well over 50% of the network hashrate currently outside of known pools. Considering these circumstances it is wise to wait for extra confirmations on transactions for payment finality.”

"Data from GrinScan shows the attackers were able to reorganize at least one forked block, at 23:17 UTC on Nov. 7. The unknown mining group has also increased its control since Saturday, commanding 58.1% of GRIN’s hash rate at the time of publication. 2Miners’ has risen to 24.6%, while sparkpool miners’ has dropped to 11.3%."

"When a group of miners controls more than half of a network’s mining power, it can affect the organization of blocks, potentially causing volatility in the token price and disrupting confidence in the blockchain. However, a mining group having control of 51% or more of a network’s hash rate does not necessarily mean it has ill intentions — sparkpool has had up to 60% of the network’s hash power before and reportedly did not interrupt the production of new GRIN blocks."

"GRIN coins were down 2.23% to $0.235 at press time." "Currently, the price of grin is trading for $0.233 per coin, and there’s $3.4 million in global trade volume. The price of grin (GRIN) has lost 2.9% during the last 24 hours of trading. Most of the slide is due to the entire market downturn, as the 51% attack threat hasn’t really affected the price much at all this past weekend."

"Crypto Briefing also learned that the Grin team has notified all exchanges about the situation and is working with them to prevent hackers from spending any forked coins."

This is a global/international case not involving a specific country.

The background of the exchange platform, service, or individuals involved, as it would have been seen or understood at the time of the events.

Include:

• Known history of when and how the service was started.
• What problems does the company or service claim to solve?
• What marketing materials were used by the firm or business?
• Audits performed, and excerpts that may have been included.
• Business registration documents shown (fake or legitimate).
• How were people recruited to participate?
• Public warnings and announcements prior to the event.

Don't Include:

• Any wording which directly states or implies that the business is/was illegitimate, or that a vulnerability existed.
• Anything that wasn't reasonably knowable at the time of the event.

There could be more than one section here. If the same platform is involved with multiple incidents, then it can be linked to a main article page.

The Reality

This sections is included if a case involved deception or information that was unknown at the time. Examples include:

• When the service was actually started (if different than the "official story").
• Who actually ran a service and their own personal history.
• How the service was structured behind the scenes. (For example, there was no "trading bot".)
• Details of what audits reported and how vulnerabilities were missed during auditing.

What Happened

The specific events of the loss and how it came about. What actually happened to cause the loss and some of the events leading up to it.

Key Event Timeline - Grin Token 51% Attack

Date	Event	Description
November 7th, 2020	Main Event	Expand this into a brief description of what happened and the impact. If multiple lines are necessary, add them here.

Technical Details

This section includes specific detailed technical analysis of any security breaches which happened. What specific software vulnerabilities contributed to the problem and how were they exploited?

Total Amount Lost

The total amount lost is unknown.

How much was lost and how was it calculated? If there are conflicting reports, which are accurate and where does the discrepancy lie?

Immediate Reactions

How did the various parties involved (firm, platform, management, and/or affected individual(s)) deal with the events? Were services shut down? Were announcements made? Were groups formed?

Ultimate Outcome

What was the end result? Was any investigation done? Were any individuals prosecuted? Was there a lawsuit? Was any tracing done?

Total Amount Recovered

There do not appear to have been any funds recovered in this case.

What funds were recovered? What funds were reimbursed for those affected users?

Ongoing Developments

What parts of this case are still remaining to be concluded?

General Prevention Policies

51% attacks can be prevented through a mix of increased block confirmation times and setting checkpoints to prevent large-scale reorganizations. This means the exchange will not credit newly deposited funds, and nodes will be prevented from accepting attacking chains.

Individual Prevention Policies

No specific policies for individual prevention have yet been identified in this case.

For the full list of how to protect your funds as an individual, check our Prevention Policies for Individuals guide.

Platform Prevention Policies

Policies for platforms to take to prevent this situation have not yet been selected in this case.

For the full list of how to protect your funds as a financial service, check our Prevention Policies for Platforms guide.

Regulatory Prevention Policies

No specific regulatory policies have yet been identified in this case.

For the full list of regulatory policies that can prevent loss, check our Prevention Policies for Regulators guide.