Bitcoin Mempool Growing Due to Low-Fee Transactions

The number of unconfirmed transactions is quickly mounting once again. Some are asserting this to be a spam attack by BCH supporters, although there is no proof to back that up. Luckily, it seems that network fees have not been affected in a significant manner so far.

Bitcoin Mempool Fills Up Quickly

It seems that in the case of Bitcoin, the mempool will hardly ever be empty. That is a positive sign showing that people are broadcasting transactions on the network. Once SegWit locks in, an increasing number of transactions will become less and less of a problem. Until then, we may have another mempool issue on our hands if the number of unconfirmed transactions continues to increase at the current rate.

At the time of writing, there were over 13,000 unconfirmed Bitcoin transactions. That number is not all that large, considering the network had to deal with nearly 200,000 such transactions just a few months ago. However, it is rather odd that there were very few unconfirmed transfers 24 hours ago and things have been slowly picking up. It is possible that the mounting Bitcoin price may have something to do with this.

As one might expect, people have been moving their coins to and from exchanges when the price has moved in either direction. Although these transactions normally do not create noticeable backlogs, in this case they will be intermixed with other unconfirmed transactions. According to Reddit, we are witnessing another “spam attack” on the network due to someone — or perhaps multiple entities — sending dust transactions back and forth to clog up network blocks. If that is indeed the case, it would not be the first time it has happened.

It is hard to blame this issue on people who may not even have anything to do with it. Considering the mempool has been filling up a lot slower than it could have if this were a proper spam attack, it is hard to figure out what is really going on. That being said, the mounting number of unconfirmed transfers has been accelerating. We started writing this article at 13,000 and are now up to 14,000 a few paragraphs later.

There are a lot of transactions with fees of less than 5 satoshi per byte. This has drawn some parallels to the previous spam attacks Bitcoin users have been having to deal with in recent months. It is possible someone else is behind this new attack as well. Once the “attack vector” is known publicly, it only takes one or two individuals with malicious intent to recreate the scenario and flood the network.

It seems that network blocks clear out approximately 10% of the waiting transactions right now, indicating that this is only a minor issue at best. If the problem persists, however, it may portend another major spam attack against the Bitcoin network. Doing so would not make much economic sense, but it never has in the past either.