{"id":7372,"date":"2021-07-14T03:07:32","date_gmt":"2021-07-14T03:07:32","guid":{"rendered":"https:\/\/3.26.50.104\/?page_id=7372"},"modified":"2021-08-05T04:23:01","modified_gmt":"2021-08-05T04:23:01","slug":"what-is-double-spending","status":"publish","type":"page","link":"http:\/\/3.26.50.104\/education\/what-is-double-spending\/","title":{"rendered":"What is double spending?"},"content":{"rendered":"\t\t
\n\t\t\t\t\t\t\t
\n\t\t\t\t\t\t\t
\n\t\t\t\t\t\t
\n\t\t\t\t\t
\n\t\t\t
\n\t\t\t\t\t\t\t\t
\n\t\t\t\t\t\t
\n\t\t\t\t\t
\n\t\t\t
\n\t\t\t\t\t\t\t\t
\n\t\t\t\t
\n\t\t\t\u2190 Back<\/a>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t
\n\t\t\t

What is double spending?<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t
\n\t\t\t
\n\t\t\t\t\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\"\"\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
\n\t\t\t\t\t\t
\n\t\t\t\t\t
\n\t\t\t
\n\t\t\t\t\t\t\t\t
\n\t\t\t\t
\n\t\t\t
Definition<\/h6>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\t\t\t\t

Double spending\u00a0is the risk that a digital currency\u00a0can\u00a0be spent twice, undermining trust in the network and essentially making the currency worthless.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

\n\t\t\t\t\t\t
\n\t\t\t\t\t
\n\t\t\t
\n\t\t\t\t\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\"\"\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t
\n\t\t\t

Understanding the problem of Double Spending<\/h4>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\t\t\t\t

Double spending is one of the main challenges faced by all cryptocurrencies<\/a>. It is essentially where a unit of crypto can potentially be spent twice, meaning false and illegitimate transactions could occur.

If double spending was to occur successfully, it would completely undermine the security & trust of the entire network, destroying any value that digital currency had.<\/p>

This problem is why digital currencies<\/a> like Bitcoin use Blockchain technology<\/a> combined with complex cryptographic algorithms to secure and uphold their ledger of transactions & balances. In order to fully understand how cryptocurrency solves the double spending problem, it helps to have a grasp of what the Blockchain is, which you can learn about here<\/a>.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

\n\t\t\t\t
\n\t\t\t
Why is double spending a problem?<\/h5>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\t\t\t\t

Since Bitcoin and other cryptocurrencies are actually digital files, they are easier to duplicate than money, and theoretically someone could pay for two separate things with the same unit of cryptocurrency.<\/p>

Bitcoin was the first digital currency to solve the problem of double spending through its Blockchain\u2019s Proof of Work<\/a> mechanism, more commonly known as \u2018Bitcoin mining<\/a>\u2019.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

\n\t\t\t\t
\n\t\t\t
A simplified explanation of solving double spending<\/h5>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\t\t\t\t

To understand how Bitcoin\u2019s Blockchain\u2019s solves the problem of double spending, a basic knowledge of Bitcoin mining, timestamps and hash functions is recommended. However, if you just want a high-level overview of how it works, here\u2019s a very simplified explanation:<\/p>

  1. On any Blockchain, there are many nodes (computers) constantly communicating with each other, creating a\u00a0peer-to-peer<\/strong> network

    <\/strong><\/li>
  2. If I send you 0.2 of one Bitcoin, for example, that information (and the time of the transaction) is sent to all the nodes on the Bitcoin network

    <\/li>
  3. Every node on the network will then save the information that you now have 0.2 Bitcoin, and I no longer possess it

    <\/li>
  4. If I was to try to spend that 0.2 Bitcoin I just gave you again (double spending), the network would block this transaction as it knows that I already gave you that 0.2 Bitcoin BEFORE I made the second transaction

    <\/li>
  5. Thus, the double spending problem is solved through the magic of Blockchain\u2019s peer-to-peer network!<\/li><\/ol>

    While this is a highly simplified version of how double spending is solved, it\u2019s enough to get a basic understanding of how it works. For a slightly deeper dive into how it all works, let\u2019s see what goes on behind the scenes.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

    \n\t\t\t\t
    \n\t\t\t
    Bitcoin Mining \u2013 the ingenious solution to double spending<\/h5>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
    \n\t\t\t\t
    \n\t\t\t\t\t\t\t\t

    Bitcoin Mining<\/a> involves \u2018miners\u2019 all around the world solving complex mathematical puzzles with powerful computers in order to serve two<\/strong> primary purposes<\/strong>:<\/p>

    1. To validate the legitimacy of a transaction, helping to avoid fraudulent transactions & the problem of double spending

      <\/li>
    2. To create new Bitcoin, rewarding miners in newly created Bitcoin for performing the previous task<\/li><\/ol>

      Whichever miner solves this puzzle (and validates their group of transactions) first<\/strong> will be allowed to bundle their transactions into a \u2018block\u2019<\/strong> and broadcast their solution or \u2018Proof of Work\u2019 to the entire network<\/strong>, so it can be checked by everyone else.<\/p>

      If the majority<\/strong> of nodes\/miners in the network agree that the solution to the puzzle is correct and the transactions are valid and coherent with the previous version<\/strong> of the ledger, the block of validated transactions are cryptographically hashed to the previous block and added to the ledger.<\/p>

      I know this can be a little confusing, so let\u2019s breakdown exactly how the problem of double spending is solved by the Blockchain\u2019s Proof of Work system.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

      \n\t\t\t\t
      \n\t\t\t
      How does Blockchain prevent double spending?<\/h5>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
      \n\t\t\t\t
      \n\t\t\t\t\t\t\t\t

      To prove that no attempts to double spend have occurred, Bitcoin\u2019s Blockchain provides a way for all<\/strong> miners\/nodes in the network to be aware of every transaction<\/strong>. With a network like Bitcoin\u2019s, all transactions are publicly announced to everyone in the network so they can then agree on a single history<\/strong> of the ledger and the order<\/strong> in which transactions were received. The order<\/strong> is key here.<\/p>