Homework on Soft and Hard Forks - Questions

[Ciaran]

1. What is the difference between a softfork and a hardfork?

A soft fork is a tightening of the rule set that makes previously valid blocks invalid. A hard fork is a loosening of the rule set that makes previously invalid blocks valid

2. What are some of the reasons why you would do a hardfork?

To create a clear update that allows people who disagree with the rule changes to stay on their own chain and people who want the rule changes to create their own chain with a different currency

3. What are some of the risks with performing a hardfork?

Split the community and the hash power used for mining the chains (making them both less secure)

[Erik_BTC]

1. What is the difference between a softfork and a hardfork?

If hardfork, previous unvalid blocks become valid, the network split and the 2 block chains keep on living their own life.

If softfork, the losing fork becomes invalid after a while when all miners chose the longest chain as current winning chain.

2. What are some of the reasons why you would do a hardfork?

If a community for example wants to build a new currency, they can make a fork of Bitcoin to become Bitcoin Cash.

If they i.e. want to increase the block size or do other expansive changes. (Change of consensus rules).

3. What are some of the risks with performing a hardfork?

You can split a community.

The new fork can risk not being taken seriously and die out ++.

[jjohnson]

1. What is the difference between a softfork and a hardfork? Softfork is an update that makes previously vaild blocks invalid. Hardfork is an update that split the chains and make previously invalid blocks valid, which can be seen as an expansion.

2. What are some of the reasons why you would do a hardfork? If there is a change in the consensus rules and vision of the nodes.

3. What are some of the risks with performing a hardfork? The community will be split, new currencies will be created, the has power will be split which reduces the security.

[manted]

1. What is the difference between a softfork and a hardfork?
   HF makes previously invalid block valid and SF makes previously valid block invalid

2. What are some of the reasons why you would do a hardfork?
   money, you can create new currency, clear updates - you will update to new set of rules and you carry on on new fork

3. What are some of the risks with performing a hardfork?
   you will split community therefor there is less hash power because some stay and some will go with new fork. Blockchain is not as secured as it used to be due to less miners on it.
   creating competing cryptocurrency

[cincinnato]

In case of soft fork the blocks mined before would not be valid according the new parameters. In case of hard fork they will continue to be valid. For example: for BTC to expand the size of the blocks would be a HARD fork since the previous blocks continue to be valid according the new rules. This is anyway explained by Filip in the lectures.

[Belle3]

1. What is the difference between a softfork and a hardfork?
   Softfork is an update that makes previously valid blocks invalid. While hard fork is an update that makes previously invalid blocks valid.

2. What are some of the reasons why you would do a hardfork?
   With hardfork, you will have democratic updates, new currencies, and it’s clear where you will end up.

3. What are some of the risks with performing a hardfork?
   Hardforks make changes that do not work within the current rule set. They split the hash rates and the community as well.

[vale_dinap]

— My anwers —

1. Softfork is an update that makes the blockchain rules more strict (so part of the originally valid blocks become invalid), hardfork is an update that makes the blockchain rules less strict (in other words blocks originally considered invalid become valid).

2. Avoid confusion, create a new coin, let each member of the community decide independently to accept the new rules or not.

3. Splitting the community, splitting the hash power (therefore reducing the security of the network), creating a new coin (if this is not wanted).

NOTE - In the lesson about pros and cons is said that soft forks are less democratic than hard forks: I believe this is not true by definition, as in a “democracy” the majority decides for all (exactly like it happens in softforks); instead, rather than democracy, what happens in hardforks is more similar to an “anarchic democracy” (where the group splits if decisions are not agreed by 100% of the members).

[Mauro]

@AR.18

2- You would have a hard-fork to have everyone on the same page with a clear update. Either everyone has to get on with the new update or you can’t mine with the new update and continue with the old rules and thus it causes a hard fork.

A split in the chains is caused when a portion of the nodes updates, and a portion does not. If everyone updates or nobody updates, there would be no split in the chain.

[Mauro]

@Erik_BTC

1. What is the difference between a softfork and a hardfork?

If hardfork, previous unvalid blocks become valid, the network split and the 2 block chains keep on living their own life.

If softfork, the losing fork becomes invalid after a while when all miners chose the longest chain as current winning chain.

A hard fork does not necessarily need to cause a network split. A soft fork cannot cause a network split.

[Mauro]

I understand you now. Your answer was correct.

[Mauro]

@Belle3

2. What are some of the reasons why you would do a hardfork?
   With hardfork, you will have democratic updates, new currencies, and it’s clear where you will end up.

Hard fork can be dangerous. We can’t be sure that everyone will want to update. In case they don’t, we will have a split in the community. In case they do everything will be perfect. A hard fork does not have a clear path in my mind.

[a.ekasdornkorn]

1. What is the difference between a softfork and a hardfork?

A soft fork makes previously valid blocks invalid. A hard fork makes previously invalid blocks valid.

2. What are some of the reasons why you would do a hardfork?

Fixing bugs, or correcting (for some reasons) the protocol mechanism. The consequence is that if network splits then we have two currencies; or the other end, no update were honored and things stay put.

3. What are some of the risks with performing a hardfork?

As it can cause network splits, there are potential risks in weakening the security as member nodes will have to choose either staying with old chain or migrate to new chain.

[TrevPeter]

1. Softworks updates are backwards compatible. Hard forks are not backward compatible.
2. It is more clear and democratic.
3. Splitting into 2 coins.

[Marc-C]

1. What is the difference between a softfork and a hardfork?Soft forks make previously valid blocks invalid and hardforks make previously invalid blocks valid.
2. What are some of the reasons why you would do a hardfork? The community sees a change in consensus
3. What are some of the risks with performing a hardfork? Hardforks will spit the chain, split the community, create a new currency, hash power splits as miners go to new chain and this can lower security

[Fabrice]

@TeresaK

Thanks Fabrice. One final question. For those users who have not adopted the soft fork to Segwit; does that mean that they are using the old rules which means security is compromised?

No, it’s just to make it backwards compatible. But most nodes have updated. But not all wallets and users are using segwit native addresses etcetera. For example, If you have recieved bitcoin on a segwit native address (bech32), some wallets will not show this UTXO (yet)

[AliasFresh]

1. What is the difference between a softfork and a hardfork?

A hard fork expands the protocol making more blocks valid (previously invalid blocks included) while a soft fork does the opposite. A hard fork will also split or fragment the chain/community resulting in a new coin.

2. What are some of the reasons why you would do a hardfork?

It’s what the people want is the reason with the most weight. To combat potential fraud is another. To correct an error or make a new coin with a new “vision” to save a projects original vision. However all of these boil down to what the people want aka consensus.

3. What are some of the risks with performing a hardfork?

A hard fork splits the chain, splits the community and affects the hash. All of these will weaken the project. (Particularly the hash rate as this effects the security and efficiency of the chain)

All of these have negative potential but non more than splitting the community.

A deep enough split can kill a project.

RIP

[unwise_guy]

1)The difference between the two is that a soft fork reduces the byte size of accepted blocks making previously accepted blocks invalid, where as a hard fork increases the byte size of accepted blocks and make previously invalid blocks valid.

2)Reasons for a hard fork update are that you get a clear update across the network and create new currency.

3)Cons to having a hard fork update are that it can cause a split in the chain that is permanent, a split in the community as it is a democratic decision to accept the new update and as a result of these cons it can further cause the network to lose some security as the hash power is split.

[Cr1ptoM]

@ivan

• What is the difference between a softfork and a hardfork?
• What are some of the reasons why you would do a hardfork?
• What are some of the risks with performing a hardfork?

1.- Soft Fork makes previous valid blocks invalid and can be considered it makes the rule set for consensus smaller, in the opposite a hard fork makes previous invalid blocks valid, making the rule set larger.

2.- One of the reason it’s you will force all nodes to update and adopt the new rule set, otherwise it will be on a different chain

3.- The major risk it’s you could split the chain with a hardfork, split the community and lose some hash power

[Sintrality]

1. What is the difference between a softfork and a hardfork?

   A softfork makes previously valid blocks invalid. A hardfork makes previously invalid blocks valid.
   

2. What are some of the reasons why you would do a hardfork?

    When you want to change the consensus, sometimes forcing that change on the network.
   

3. What are some of the risks with performing a hardfork?

   Reducing the hashpower/security of the network, community split.

[yestome]

1. Hard forks expand the rule set while soft forks contract the set of rules. Hard forks will always lead to a split of the chain as part of the community will decide not to comply with the new set of rules and continue working on their now forked chain to create a new currency (BitcoinCash, BitcoinSV, etc.). Soft forks will initially split the chain into 2 accepted chains, and over time the chain that adds new blocks more quickly by adding more PoW will become the accepted chain and the other chain will be dropped, the split will disappear.
2. Adoption of novel technologies, plug security risks, add new functionality, (reverse transactions as seen in the DAO hack of Ethereum),
3. a) Miners might decide to leave the original chain and provide their hashing power to the forked chain therewith creating a security issue as reduced hashing power will lead to a decrease is security of the original chain
4. b) It might weaken the consensus and split the community
5. c) It dilutes the value of the original chain as there is a common past and question how the old currency is to be migrated to the new forked chain / currency.