Bitfinex Bitcoin Gold 51% Attack

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Bitfinex

In 2018, a string of Bitcoin Gold 51% attacks targeted multiple platforms including Bitfinex. In response to these attacks, the block confirmation times were increased.

This exchange or platform is based in Hong Kong, or the incident targeted people primarily in Hong Kong.

About Bitfinex

"Bitfinex is a Hong Kong-based cryptocurrency exchange owned and operated by iFinex Inc., which is headquartered in Hong Kong and registered in the British Virgin Islands." "The Bitfinex exchange is a popular platform for exchanging cryptocurrencies, also hosting spot and derivatives trading as well as certain lending, borrowing and staking features. Bitfinex came into existence in 2012." "BitFinex offers three main functions - it is a pure bitcoin to fiat exchange, a margin trading exchange and a liquidity provider. The platform offers a number of features available that expand the financial positions you can take - for example, the ability to short Bitcoin via margin trading."

"Bitcoin Gold was the second fork of Bitcoin when it went live in November 2017 (amidst a few technical issues that occurred pre-launch). Albeit being marketed as a cryptocurrency supporting decentralized mining through an ASIC-resistant mining algorithm, critics of the cryptocurrency called it a “cash grab.” Yet, most bitcoin holders were given free BCG coins relative to their holdings of Bitcoin, so most welcomed the “free money.”"

"In a May 11th blog post, the Bitcoin Gold team made Bitcoin Gold (BTG) holders aware of attempts to attack the Bitcoin Gold network. Exchanges were also asked to guard against the attack since potential attackers were likely to profit by double spending coins in exchange transactions. The blog post was updated on the 24th of May to announce that a dreaded 51% attack occurred on the network between the 16th and the 19th of May 2018. The attack on Bitcoin Gold also involved rented hashpower from cloud mining services."

"Traders of the coin, established in 2017 through a hard fork of the main Bitcoin (BTC) network, have been tracing the attack since last week."

"Scrutiny of unusual activity on the network has revealed the scheme, in which "double spending" attacks have been launched against cryptocurrency exchanges trading the virtual currency."

"A Bitcoin Gold wallet linked to the double spend scheme has received over 388,000 BTG, which is currently worth about $18 million, according to data from CryptoCompare. Most of the coins have now been transferred to various other addresses and only about 13,000 BTG are left in it."

"Bitcoin Gold—already one of the worst performing cryptocurrencies in 2018—faced even more problems after the attack. Bittrex delisted BTG following the BTG team’s refusal to pay compensation of 12,372 BTG. Exchanges including Bittrex, Binance, Bithumb, Bitinka, and Bitfinex lost an estimated $18 million worth of coins due to the double spend attack. Bittrex blamed the Bitcoin Gold team for negligence and demanded compensation in order to keep the cryptocurrency listed."

"In response, the Bitcoin Gold team stated that 51% attacks are a known risk in the ecosystem. They added that the BTG organization was not responsible for the attack since it was not caused by flaws in the Bitcoin Gold blockchain or code. Additionally, the team cited warnings it gave prior to the attack as well as the assistance it gave exchanges for defending themselves."

"The BTG team also claimed that the network upgrade carried out in July 2018 will reduce the likelihood of another attack on the network. Bittrex ended up delisting the coin, along with several others. Bitcoin Gold still survived as the 27th most capitalized coins on CoinMarketCap."

This exchange or platform is based in Hong Kong, or the incident targeted people primarily in Hong Kong.

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 - Bitfinex Bitcoin Gold 51% Attack

Date	Event	Description
May 11th, 2018	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 rollbacks. This means the exchange will not credit deposited funds, or nodes will be prevented from accepting the attacking chain.

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.