Hash Algorithm AND BIP | Bitcointalksearch.org

RandomQ

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Quote from: jgarzik on July 14, 2012, 07:28:19 PM

Quote from: RandomQ on July 14, 2012, 06:51:59 PM

Would it be possible to force a blockchain change without having the processing power to backup that block chain switch?

There is no "force", there is choice. Each user chooses the software they run to validate the chain. If a majority of users choose to switch to SHA-512, that is what will happen, regardless of the number of miners who switch.

51% hashing power, or even 90%, means nothing if clients collectively refuse to accept and relay your blocks.

I was thinking it terms of miners/hardware/etc. 51% computing Power.

But I should be thinking about clients, because it all depends on the amount of clients that switched and computer power doesn't matter.

jgarzik

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Quote from: RandomQ on July 14, 2012, 06:51:59 PM

Would it be possible to force a blockchain change without having the processing power to backup that block chain switch?

There is no "force", there is choice. Each user chooses the software they run to validate the chain. If a majority of users choose to switch to SHA-512, that is what will happen, regardless of the number of miners who switch.

51% hashing power, or even 90%, means nothing if clients collectively refuse to accept and relay your blocks.

RandomQ

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Quote from: jgarzik on July 14, 2012, 06:27:50 PM

Well, for one, SHA-3 does not exist.

Not till the end of the year.... Go JH! lol

But you can throw any algorithm name in the title...whirlpool

I was just using SHA-3 as an example

I edited the orginal post title from SHA-3 to Hash Algorithm

RandomQ

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Quote from: theymos on July 14, 2012, 06:35:00 PM

Quote from: maaku on July 14, 2012, 05:52:10 PM

Ultimately there should be a set of procedures for switching the community from one hash algorithm to another

https://en.bitcoin.it/wiki/Contingency_plans#SHA-256_is_broken

BIP34 creates Version 2 of the blockchain and the process of switching from Version 1 to Version 2

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Lets say we are at 95% of miners using blockchain version 2

Lets say there is a weakness found in SHA-256

Lets just say 51% of the network uses devices that can only DO SHA-256.

And its in there best interest to not change the algorithm because there hardware would no longer work with a changed algorithm.

Would it be possible to force a blockchain change without having the processing power to backup that block chain switch?

theymos

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Quote from: maaku on July 14, 2012, 05:52:10 PM

Ultimately there should be a set of procedures for switching the community from one hash algorithm to another

https://en.bitcoin.it/wiki/Contingency_plans#SHA-256_is_broken

theymos

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Quote from: satoshi on June 14, 2010, 03:39:50 PM

SHA-256 is very strong. It's not like the incremental step from MD5 to SHA1. It can last several decades unless there's some massive breakthrough attack.

If SHA-256 became completely broken, I think we could come to some agreement about what the honest block chain was before the trouble started, lock that in and continue from there with a new hash function.

If the hash breakdown came gradually, we could transition to a new hash in an orderly way. The software would be programmed to start using a new hash after a certain block number. Everyone would have to upgrade by that time. The software could save the new hash of all the old blocks to make sure a different block with the same old hash can't be used.

jgarzik

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Well, for one, SHA-3 does not exist.

In general, bitcoin users and miners may collectively choose to do anything they wish.

Changing the hash algorithm is a "hard fork" that makes new bitcoins unspendable by old clients, and therefore, is a change only undertaken under the most dire of circumstances.

RandomQ

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SHA-0 was published in 1993
SHA-1 was published in 1995
SHA-2 was published in 2001

How long before SHA-2 was published was it designed? 1.3,5,10 years?
How long before it was published was it cracked?

But back to the topic on hand.

Quote

Ultimately there should be a set of procedures for switching the community from one hash algorithm to another, but there's really no reason to do it proactively.

Do you think it should be done proactively to increase the bit count IE 256 to 512 to 1024?
IE SHA 256 to SHA 512?

A quote I found online about this topic

"I don’t have much to say about Bitcoin, but I do find it interesting that, however briefly, there exists a direct monetary incentive to break SHA-256. To my knowledge, there is no provision for changing the cryptographic hash function for Bitcoin."

maaku

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Quote

I've been reading a few post about people thinking SHA-256 is going to last another 10 years?

Not sure where you heard that. SHA-2 will last a thousand years if it is secure. It could be dethroned overnight if a new attack is found. Though unlikely, it could end up that SHA-3 is attacked before SHA-2.

Ultimately there should be a set of procedures for switching the community from one hash algorithm to another, but there's really no reason to do it proactively.

RandomQ

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Can the BIP Process be used to switch the client from SHA-2(SHA-256) to SHA-3 in the future( Go JH!) ? or any other algorithm.

I've been reading a few post about people thinking SHA-256 is going to last another 10 years?

I wanted to see what other people think?

I edited the orginal post title from SHA-3 to Hash Algorithm

Topic: Hash Algorithm AND BIP (Read 1742 times)