Homework on Soft and Hard Forks - Questions

[zinovsky]

1. What is the difference between a softfork and a hardfork?
   Softfork is when an update of the chain makes the previous valid blocks invalid
   Hard fork is when an update of the chain makes the previous invalid blocks valid

2. What are some of the reasons why you would do a hardfork?
   Total agreement of the nodes for the update - Democraty-

3. What are some of the risks with performing a hardfork?
   The main risks if there is no total agreements of the nodes, that will split the network which will result in spliting the hash rate between the old chain and the new one, this split of hash rate will decrease security in the old chain

[Nick]

1. A hardfork makes previously invalid blocks valid. A softfork makes previously valid blocks invalid.
2. To change the consensus rules or improve performance
3. Reduced hashpower and potentially split community

[David_Walsh]

@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. Softforks make previously valid blocks invalid by contracting the rule set for block validation with an update. Hardforks make previously invalid blocks valid by expanding the rule set for block validation with an update. These updates are not retroactive so blocks appended to the blockchain before the update are unaffected.

2. A hardfork update can be done to expand the rule set to give the blockchain more functionality and to create a new consensus by splitting the blockchain into 2 separate blockchains permanently, creating a new Bitcoin like Bitcoin Cash.

3. A hardfork update is deemed to be more difficult to do than a softfork because a softfork only needs <50% of the network’s hashing power to accept it to update without causing a permanent split in the chain but a hardfork can be caused by a minority of nodes who choose to not follow the majority resulting in the hashing power being split between the 2 chains reducing security and confidence in Bitcoin.

[Mauro]

@Srdjan_Vlatkovic

With hardfork there is a new chain being created,with softfork all nodes eventually comply to the new rule chain

@frabosce

1. What is the difference between a softfork and a hardfork?
   The main difference is that with a hard fork the blockchain and the community are splitted in two and with soft forks it doesn’t.

@Lisalazuli

1. What is the difference between a softfork and a hardfork? A hard fork results in a permanent fork in the chain as two valid branches arise, as a result of a rule change, which creates in effect a new currency like bitcoin gold or bitcoin cash. Both forks are valid. A soft fork is usually created when the rules get tighter IE mB size of a block reduced. Once over 50% of the network adopts the rule change, one of the forks created will be rejected and the single strand chain is restored. Soft forks are usually resolved and don’t result in a permanent fork.

A hard fork will cause a new chain, but it does not mean it will create 2. If everyone updates then we will only have 1 chain, and if everyone declines we will also have 1 chain. The problem comes when there is a disagreement between nodes on the update. This causes a chain split, and all the things you mentioned in the third answer. An example: If we proposed an update to increase the supply of bitcoin. This would never be accepted by any node, meaning we will not have 2 chains, but only 1. It would be like nothing happened.

A soft fork may or may not be adopted over time. We cannot be sure if all nodes will eventually comply. For example: If we pushed a soft fork that decreases the block size from 1mb to 0.5mb. This would never be adopted, as miners are driven by incentives.

@Lisalazuli A soft fork cannot cause a chain split since its a contraction of the rules. If you don’t udnerstand why. feel free to message me. I will try my best to explain it.

[Mauro]

@MarkM

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

So that every node is following the same set of rules after an update. A hardfork gives a “clear” update.

Any examples? My example: Changing the blockchain consensus from POW (Proof of Work) to POS (Proof of Stake). Do you think you could post a different example that would require a hard fork?

[Mauro]

@zinovsky

2. What are some of the reasons why you would do a hardfork?
   Total agreement of the nodes for the update - Democraty-

Can you give an example? What kind of an update would need a hard fork?

[Mauro]

@Nick

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

Its the opposite. A softfork makes previously valid blocks invalid, and a hard fork makes previously invalid block valid.

Here is an example:

Current block size is 1MB.

Soft Fork (We are decreasing the block size to 0.5MB) - This means that the update will make blocks larger than 0.5MB invalid. A block that was previously valid is now invalid. That’s why we say that a soft fork makes previously valid blocks invalid.

Hard Fork (We are increasing the block size to 2MB) This means that the nodes will accepting block larger than 1MB. What before was invalid will now be valid. That’s why we say that a hard fork makes previously invalid block valid.

If you are still struggling to understand, feel free to message me. I will try my best to explain it to you.

[zinovsky]

Example of an update is the augmentation of the size of the block

[Mauro]

@David_Walsh

3. A hardfork update is deemed to be more difficult to do than a softfork because a softfork only needs <50% of the network’s hashing power to accept it to update without causing a permanent split in the chain but a hardfork can be caused by a minority of nodes who choose to not follow the majority resulting in the hashing power being split between the 2 chains reducing security and confidence in Bitcoin.

A soft fork can’t cause a chain split. It either gets adopted or not. If we have a hard fork and only a couple of percent don’t update we shouldn’t worry too much about it. The problem comes when we have a hard fork and 50% decide to update and 50% don’t want to. 60/40 70/30 80/20 are also pretty bad.

[Mauro]

Correct. Keep up the great work.

[cryptomarls]

Thanks for the feedback. That’s a very good point i should have elaborated…

[CryptoTube]

1. Hard forks make invalid blocks valid and Soft forks make valid blocks invalid.
2. A Hard fork can occur when they want change the consensus rules.
3. There is a possibility that the community could split and not accept it causing the security to lower.

[tanyiakandohla]

• What is the difference between a softfork and a hardfork?

Hard forks make previously invalid blocks valid and vice versa.
Hard forks require 100% adoption by the node network and soft forks require a majority
Hard forks create a chain split, power split and new currency but they are a clear update. Soft forks could cause some confusion which may effect security.

• What are some of the reasons why you would do a hardfork?
  Fundamental philosophy shift

• What are some of the risks with performing a hardfork?
  Chain split
  Hash power split and weakened security
  Community split

[MarkM]

To add new functionality. Bitcoin Cash was made using a Hard Fork. Also if i wanted to reverse a transaction, but that would cost more money to do than just sticking with the existing blockchain. Are those good examples?

[David_Walsh]

Ok thanks for clarifying. I forgot that the longer chain with the most proof of work will be the one that continues and the shorter chain will be discarded like with an accidental fork. So there wont be any alternative for people who aren’t happy with the update or the lack of an update depending on which way it went.

[CocoaCrypto]

1- There are many differences between soft and hard forks. For example, a hard fork means there will definitely be a split chain, therefore splitting the hash power between the chain with the previous version and the chain with the update. For a hard fork to occur, not all nodes need to be in agreement about the new rule, thus it is more democratic.

A hard fork is an expansion of a rule set and it makes previously invalid blocks valid. Because it takes time for all of the nodes to get the update, some would still be rejecting blocks that were considered invalid before the new rule while adding blocks that do fit the new rule, thus creating 2 different versions of the chain.

A soft fork is a contraction of the rule set, so it makes previously valid block invalid. In this case, there is not always a fork. It depends on hash power. If there is > 50% hash power, there won’t be a fork. However, if there is < 50% hash power, a fork will occur. So majority rule and the other nodes are forced to stay on the main chain.

2- Perhaps you would do a hard fork because you want to create a new crypto currency with a different set of rules.

3- There is a split in hash power and a split in the community. The hash power is how quickly computers on the network can perform hash functions, so any decrease in power can cause an issue.

This topic was quite confusing to me actually! My question is, if there is a fork because of the less than 50% of the hash power rule, why did Filip (instructor) state that all the nodes are forced to stay on the main chain in a soft fork??

[Lacho]

[ *** What is the difference between a softfork and a hardfork?**
Softfork : Makes previous valid blocks invalid.
Hard Forks:previous invalid blocks valid.
*** What are some of the reasons why you would do a hardfork?**
To make the size of the block bigger.And consensus need to be changed.
***** What are some of the risks with performing a hardfork?**
The chain can be split.
The community can be split as well.
Hash power split and has a security risk.

[Lacho]

[ *** What is the difference between a softfork and a hardfork?**
Softfor : Makes previous valid blocks invalid.
Ward Forks:previous invalid blocks valid.
*** What are some of the reasons why you would do a hardfork?**
To make the size of the fork bigger.And consensus need to be changed.
***** What are some of the risks with performing a hardfork?**
The chain can be split.
The community can be split as well.
Hash power split and has a security risck.

[kenn.eth]

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

Hardfork is a expansion of the rule set and cause a split of the blockchain, a softfork do not make split, only modify the rule set of the current blockchain, is a contraction

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

To create a new coin with a new community that follow an ideal. Because some people believe it could be better.

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

A important risk is the reduction of hashpower, this reduce the security of the network.Also split of community and lower performance.

[wafflemakr]

@Lacho

fork

Did you mean the block?