BitBet Falls Victim To Strange Bitcoin Double-Spend Behavior -

BitBet Falls Victim To Strange Bitcoin Double-Spend Behavior


Double-spending in the Bitcoin world is becoming a very rare occurrence, but that doesn’t mean it is impossible to pull off this type of attack. BitBet, an online gambling platform, fell victim to such an attack earlier today as a result of several of their transactions not being included in the Bitcoin Node mempool. This entire situation is sparking a lot of debate and conspiracy theories as to why one particular transaction was broadcasted twice on the network, although it is rather a stretch to claim malicious intent at this stage.

Also read: Bitcoin Gains Smart Contract Functionality With Zero Knowledge Contingent Payments

BitBet Transactions Not Picked Up By Bitcoin Nodes

Bitcoinist_Strange Bitbet

The goal of online gambling platforms such as BitBet is to pay out winnings as soon as possible. In this particular event, the company sent out a Bitcoin transaction with no fee attached, which is not a good way to ensure the information is picked up by Bitcoin Nodes and put into the mempool queue.

That BitBet transaction was not included in any of the mined blocks on the network, forcing the company to send a new transaction with a small fee. However, that fee amount was still too small to be noticed by the Bitcoin network, and the second transaction remained unconfirmed as well. Do keep in mind this delay had nothing to do with the kerfuffle going on with the Bitcoin network in the past 48 hours.

Increasing the fee in a third transaction seemed to be a right call at that time, but even that transfer was not included in any of the mined blocks on the Bitcoin network. Quite a strange situation, considering how a fee of over ten satoshis per byte should warrant inclusion in one of the next network blocks. Unfortunately, no dice for BitBet, forcing them to broadcast transaction number four.

What is of particular interest is how, according to the report, transaction number four included the same inputs as all of the previous three transactions.  However, that did not yield many results either, and BitBet decided to try a different approach. Five times is the charm, as some sayings go.

This fifth Bitcoin transaction used different inputs, yet the same outputs as all of the four previous transactions. Lo and behold, this transaction was picked up by Bitcoin nodes rather quickly and confirmed within thirty minutes. The issue got finally sorted, and the winners got their payouts as promised, albeit with a slight delay.

Imagine their surprise when they received a second transaction shortly afterwards, which was the very first transfer sent by BitBet. That transfer had gone unconfirmed for close to a week now, and suddenly got broadcasted by Bitcoin Nodes. It remains unknown as to why this transaction was re-broadcasted, or who was responsible for this event, but it has cost BitBet a fair amount of money.

Possible Explanations And Conspiracy Theories

Bitcoinist_Strange Bitbet Bitcoin

It didn’t take long until the first versions of a conspiracy theory started appearing. One theory is how large entities control most of the Bitcoin nodes, which would give them the power to refuse individual transactions for any reason they see fit. Such a process is called “transaction nuking” and could pose a significant threat to the Bitcoin network if this were to be the case.

Another possibility is how Bitcoin miners are forming a cartel to deliberately withhold blocks for a particular interval of time. This seems to be quite an outrageous statement, as it would require a ton of coordination to pull off these types of schemes. Last but not last, some remarks were made of how Antpool and F2pool could form a cartel and control over 51% of the mining power, allowing them to pull off these kinds of stunts.

What are your thoughts on this mysterious re-broadcasting of a week-old transaction? Let us know in the comments below!

Source: Qntra

Images courtesy of BitBet, Shutterstock

Jp Buntinx

Jp Buntinx

JP Buntinx is a freelance Bitcoin writer and Bitcoin journalist for various digital currency news outlets around the world. In other notes, Jean-Pierre is an active member of the Belgian Bitcoin Association, and occasionally attends various Bitcoin Meetups in Ghent and Brussels

  • Jonathan Cross

    They should have used Opt-in RBF :-)
    No, seriously, what were they thinking?
    No transaction fee!?

    Zero fee transactions are basically dead as of Bitcoin Core 0.12.0.

    Then sending transactions with different inputs? They should have cleared out the first inputs before signing the last transaction… This is not really a double-spend, but rather BitBet paying someone twice.

  • thirdalbum

    The original set of transactions must have had one or more unconfirmed parent inputs, and hence they did not confirm until the parents confirmed, which happened to be after the final transaction (with different inputs) confirmed.

    So why did the free transaction confirm? Miners sometimes make 750kb blocks because of old default settings in their software. Those same old settings could reserve some space for old, free transactions.

    So why the free transaction and not the later fee-paying transactions? When nodes saw the later transactions they recognised them as a double-spend and did not relay them. Some XT nodes relayed them enough to leave a record (they relay double-spends) but not enough to get them confirmed.

  • Tom Harding

    This story describes a situation that cannot possibly be the case.

    No bitcoin nodes will relay a transaction that is a double-spend of another transaction already confirmed in the blockchain.

    The XT double-spend-relay feature only applies when both transactions are unconfirmed.

  • Ashley Fulks – Bitcoin Broker

    It’s a messy state bitcoin is in right now. It’s kind of sad that many saw slow transactions coming down the pipe, but couldn’t do anything fast enough to stop it. Mike Hearn might be right, bitcoin has some serious problems to deal with. Fast transactions is a core feature of cryptocurrencies. Take that away and bitcoin becomes the ACH clearing house while faster and smarter coins like Ethereum and litecoin steal away traffic…and market cap.

  • Bruce

    It’s not a double spend. The 2 spends came from different inputs.

  • Bruce

    It’s not a double spend. The 2 spends came from different inputs.