A UASF is the way in which an update is introduced within the blockchain, with users having the decision to activate it or not. Learn here everything you should know about it, its operation and importance. 

LThe acronym UASF stands for User Activated Soft Fork (UASF) or User Activated Soft Fork. This is a mechanism activated by full nodes at a specific time, allowing the system Bitcoin be able to transition or change to a new set of rules consent. All this without causing abysmal changes in the network, such as dividing the chain in two blockchain different.

Un soft fork or soft fork, it is rather a change to the software protocol rules imposed by the complete nodes. Even with these new changes the compatibility with the previous versions of the software is maintained. This allows old full nodes to recognize new ones. blocks y Transactions as valid. And to the rest of the new nodes, work in sync with the rest of the nodes, whether or not they are updated.

To execute a UASF, the soft fork must be produced with the complete nodes in a specific time. That is, at a certain date and time. There, the full nodes must activate the new consensus rules, and reject all those blocks and transactions that do not adhere to the new rules. However, full nodes may accept or reject miner locks based on the new rules. So miners could either stick to the new consensus rules for block mining, or refuse and risk wasting resources if their blocks are rejected.

Functions of a UASF

Smooth forks were created for the purpose of create new features that subtly improve certain functions within the blockchain. Perfecting your protocol without risking the operation of the network. It is the opposite point of hard fork, where the changes can divide the blockchain network into two different chains. 

Initially, these forks are activated by miners, who control the hash power of the network. Deciding whether or not to adopt the proposed changes. But because the opinions around these bifurcations can be very varied on the part of the community. These could agree or disagree with the decisions of the miners, so the UASF concept was implemented. This change allows network participants to activate soft branching. This causes the miners, although they may reject the soft fork, simply do not do so due to the fact that they do not lose the commissions generated by the transactions and the production of blocks. A subtle way to get miners to accept changes. 

In the event that a soft fork is activated, all operations performed on the network that do not comply with the new protocol rules will be rejected. So if the miners ignore it and continue to validate with the previous rules, their mining efforts will be wasted, by approving transactions and blocks that will be invalid before the new consensus rules. Action with which they will not be able to receive any reward for the work they have done, wasting their hash rate.

Therefore, the UASF mechanism allows users to take control over miners and incentivize them to accept the new rules. So it requires a lot of coordination by the community throughout the network to activate it.

What is BIP 148?

The Bitcoin Improvement Proposal 148 BIP is a clear example of UASF, which encourages the network to implement followed in order to improve the use of block space. In order to process a greater number of transactions within the block and much faster. SegWit is a proposed change in the network that allows separating digital signatures in Bitcoin from the original section of the block, achieving better management of the space within the block.

This smooth fork does not cause any division to the Bitcoin network, but rather seeks to incentivize miners to update their software to implement SegWit. Which required at least 95% acceptance by the miners to be fully activated. 

So, as the adoption of SegWit by miners was not reaching the level expected, the developers chose to create another proposal. One that would allow full nodes to activate SegWit in a coordinated way, without the need for approval by most mining nodes. This proposal is User Activated Soft Fork o UASF

Therefore, the UASF mechanism gives power to network participants and not to miners. Hence its name user-activated soft fork

Implications of activating a UASF

As the activation of UASF does not require the approval of the miners, as in the initial case of SegWit which was at least 95%, user-activated soft forks only require community coordination. For example, private users, exchange houses, wallet services and other service providers can activate a UASF within their own Bitcoin client. For this they must specify a certain time in the future for the activation of the soft fork. 

So, with the implementation of a UASF they are encourages or compels miners to participate in the network with the new consensus rules established. Well if they reject them, they run the risk of mining blocks and validating transactions that will be rejected. Since the full nodes have not adhered to the new consensus rules. 

On the other hand, while activating a UASF may sound easy enough for even less experienced or tech-savvy users, implementing a UASF can have unintended negative consequences. For example, the implementation of a UASF is not easy and could result in a division of the Bitcoin chain. Something that is not wanted or wanted for any reason. 

Also, even though full nodes can accept the UASF, they may not activate it at any time. Or that the miners refuse to accept the implementation to some degree. What could leave users exposed to attacks from double spending while the miners accept the update

Likewise, to implement a UASF it is necessary to have at least 50% of the complete nodes, so that they are able to interrupt the transmission of the blocks generated with the old consensus rules in the main network. 

How much do you know, cryptonuta?

Is the main advantage of UASFs its ability to maintain backward compatibility?


The main utility and advantage of UASFs is that their function facilitates backward compatibility in Bitcoin, and one of the main reasons why it is widely used in this project.

Other UASF implementations

One of the best known cases of UASF occurred in the protocol of Ethereum. When a few days after starting the project DAO a hacker stole around $ 55 million from user accounts. As a result of this incident, as expected, many of the community participants were concerned and angry. 

Due to this, three main proposals emerged to solve the incident. The first proposal was simply to accept the theft and continue the project. The second proposal was to revert the blockchain to the moment before the robbery. In this way it could continue from that point as if nothing, since the robbery is as if it did not exist. And the third proposal was to accept as false all the transactions made by the hacker and return the money to the users. 

The second proposal was a hard fork or hard fork which would divide the Ethereum chain into two parts, while the third proposal was about a smooth fork or soft fork

So much of the Ethereum community chose to choose the second option. With this, the chain was reversed and the theft data was eliminated. But another part of the community that did not agree with this proposal, chose to continue with the chain according to the third proposal. This resulted in Ethereum being divided into two chains, the first known as Ethereum (ETH) and the second known as Ethereum Classic (ETC). This is a fact that shows us the scope and importance of this type of action.