Is Bitcoin's mempool corrupted?

Bitcoin’s mempool has become bloated with transactions, resulting in slower transactions, higher charges, and numerous other issues. Consequently, Steam has stopped using Bitcoin for payments, as more and more users are complaining about the higher transaction costs.

Consider mempool a region of space where transactions pass through before being accepted. Here, the transactions are verified by miners. Therefore, a transaction cannot be successfully carried out unless it quickly passes through mempool.

However, in the recent weeks it has been noticed that the size of mempool has significantly increased, as more than 100,000 transactions are waiting in the mempool at any given moment. The slowing down of transactions has already been discussed in a previous article and here we will only be discussing the possible reasons behind this stagnancy.

Currently, there are two possible reasons behind this behavior of the mempool. Either, the recent surge in price of bitcoin has significantly increased the number of users carrying out transactions, or the mempool is suffering from a spam attack consisting of low-fee transactions.

The suspicion of a spam attack has not been raised out of thin air. In fact, Bitcoin’s mempool has been hit by spam attacks previously. Just a month ago, in November, a coordinated spam attack was carried out against the mempool, resulting in halted transactions and higher fees.

The current attack is even worse than that of November and has grinded the Bitcoin network to a standstill. Others suggest that the surge in price could be the reason behind the bloated transaction volume of bitcoin.

The result is an increase in the price of transactions. For large-scale transactions comprising of thousands of dollars worth of bitcoin, the transaction cost may not matter. However, for small-scale transactions, a $10 fee is just too much.

On December 7th, the mempool’s size increased to almost 120 million bytes from the usual 70 million. This resulted in transaction costs surging to almost $30. This is a clear indication that Bitcoin needs to develop a solution to handle their large volumes of transaction.