Can Bitcoin eventually shift away from SHA256?

[mpattison]

Let's just say the NSA cracks it tomorrow... is that the end, or can the developers shift gears to a different form of encryption?

[Bigeyeone]

The devs can change the hashing protocol with a hard fork (if everyone accepts their new client of course,) but if they change from SHA 256 all the asic miners gonna be real pissed off because that would make their asics worthless over night because their asics cant do anything else, so there would be a lot of resistance.

[mpattison]

The devs can change the hashing protocol with a hard fork (if everyone accepts their new client of course,) but if they change from SHA 256 all the asic miners gonna be real pissed off because that would make their asics worthless over night because their asics cant do anything else, so there would be a lot of resistance.

Gotcha.
Is there no way to change & retain ASICs use?

EDIT: And ultimately, while it would suck for hardware owners, it is a necessity if BTC is to remain viable.

[greenlion]

Gotcha.
Is there no way to change & retain ASICs use?

EDIT: And ultimately, while it would suck for hardware owners, it is a necessity if BTC is to remain viable.

No, ASICs are hard-coded to a specific mining sha256d implementation.

FPGA's however could become relevant again.

[mpattison]

Gotcha.
Is there no way to change & retain ASICs use?

EDIT: And ultimately, while it would suck for hardware owners, it is a necessity if BTC is to remain viable.

No, ASICs are hard-coded to a specific mining sha256d implementation.

FPGA's however could become relevant again.

Very interesting!  Thanks!

[kwoody]

Switching Bitcoin protocol will be extremely difficult and risky. If petaflop power of currently implemented ASIC hardware is lost, the network would become so weak that it'd be vulnerable to anyone who can afford to spend $50ish-million on developing ASICs that use new protocol.

So switching is viable, but dangerous for the network until overall computational power is restored to the point where no single entity can easily amass 51% of hashrate. The 'problem' will worsen as time goes on and more SHA256 ASIC are added to network.

[FenixRD]

Switching Bitcoin protocol will be extremely difficult and risky. If petaflop power of currently implemented ASIC hardware is lost, the network would become so weak that it'd be vulnerable to anyone who can afford to spend $50ish-million on developing ASICs that use new protocol.

So switching is viable, but dangerous for the network until overall computational power is restored to the point where no single entity can easily amass 51% of hashrate. The 'problem' will worsen as time goes on and more SHA256 ASIC are added to network.

Luckily, the market has already created a solution to this. It's called Litecoin (only big non-SHA-256 coin at present). As for ASIC miners, their expected ROI point is usually 3 - 6 months out at most anyway; and most are aware SHA-256 will not live forever. The market will hedge its bets with a big shift to LTC if necessary, but really I doubt the actual cracking of it will be a big issue. It's unlikely to occur and be used in an attack. More likely, it will be published (maybe even with a couple weeks of heads-up lead time to Bitcoin devs, since that's the single biggest implication of it) with the details held secret until the hash function is updated and mining strength is strong (which would happen quickly, as even CPU mining would again be viable, and the circle of life of a crypto's hash function continues).

Also, please explain your logic in thinking a 51% attack is any more viable while a new hash function is in it's infancy, and everyone goes back to CPU, then GPU, etc. It seems to me that this is perhaps actually desirable, for the decentralization and prevention of 51% accumulations. I believe Satoshi would agree with me.

[mcleo]

is Scrypt vulnerable like sha256 though?

[bg002h]

is Scrypt vulnerable like sha256 though?

Neither is vulnerable...

[rarabit]

Switching Bitcoin protocol will be extremely difficult and risky. If petaflop power of currently implemented ASIC hardware is lost, the network would become so weak that it'd be vulnerable to anyone who can afford to spend $50ish-million on developing ASICs that use new protocol.

So switching is viable, but dangerous for the network until overall computational power is restored to the point where no single entity can easily amass 51% of hashrate. The 'problem' will worsen as time goes on and more SHA256 ASIC are added to network.

Luckily, the market has already created a solution to this. It's called Litecoin (only big non-SHA-256 coin at present).

Bitcoin could switch to scryp, most scrypt hashing power goes go
to bitcoin , other scrypt alts lose most of their scrypt hash power.
The biggest danger here is for alts  IMO if sha is broken.

[FenixRD]

Bitcoin could switch to scryp, most scrypt hashing power goes go
to bitcoin , other scrypt alts lose most of their scrypt hash power.
The biggest danger here is for alts  IMO if sha is broken.

You are either very confused about the mining, merged mining, and the relationship between scrypt-based chains and SHA-based chains, or I was unable to make any sense of what you wrote.

is Scrypt vulnerable like sha256 though?

Neither is vulnerable...

Or, put another way, both are just as vulnerable, in that there are not any major weaknesses known for either. Probably more attention is paid to SHA-256 which is used in regular banks and a million other places. If they are equally strong, SHA-256 would probably be broken first, in that case. It is not possible to know which is stronger until both are broken, however.

[Kazimir]

The devs can change the hashing protocol with a hard fork (if everyone accepts their new client of course,) but if they change from SHA 256 all the asic miners gonna be real pissed off because that would make their asics worthless over night because their asics cant do anything else, so there would be a lot of resistance.

Ehhh no, it's the NSA breaking SHA256 that pisses them off, not the devs taking necessary steps to keep Bitcoin alive.

What would piss off those asic miners more: their hardware becoming worthless because Bitcoin switched from SHA256 to something else, or their hardware AND all the precious bitcoins they mind becoming worthless because Bitcoin didn't switch and got effectively killed because SHA256 was broken?

Think. Miners deliberately take a risk by investing in mining hardware that could, theoretically, become worthless over night. To say it's extremely unlikely is still a vast understatement, but it's not impossible. Don't take that out on the devs.

[FenixRD]

The devs can change the hashing protocol with a hard fork (if everyone accepts their new client of course,) but if they change from SHA 256 all the asic miners gonna be real pissed off because that would make their asics worthless over night because their asics cant do anything else, so there would be a lot of resistance.

Ehhh no, it's the NSA breaking SHA256 that pisses them off, not the devs taking necessary steps to keep Bitcoin alive.

What would piss off those asic miners more: their hardware becoming worthless because Bitcoin switched from SHA256 to something else, or their hardware AND all the precious bitcoins they mind becoming worthless because Bitcoin didn't switch and got effectively killed because SHA256 was broken?

Think. Miners deliberately take a risk by investing in mining hardware that could, theoretically, become worthless over night. To say it's extremely unlikely is still a vast understatement, but it's not impossible. Don't take that out on the devs.

The logic is strong with this one.

[Notanon]

The ASICs would then get pointed at altcoins that use SHA-256 protocols, such as Peercoins and Terracoins, provided they themselves don't switch as well.

[justusranvier]

Mining hardware has such a short life cycle that it would not be difficult to schedule a changeover.

1. Pick a suitable replacement hash function and announce it. Give the ASIC designers time to prepare new chips.

2. Pick a block where the changeover happens, far enough in the future that everybody has time to get new hardware and have it ready to go when the switch happens.

It could probably be done in a year without too much disruption. Usually hash functions don't fail all at once so that should be plenty of time.

[wachtwoord]

Switching Bitcoin protocol will be extremely difficult and risky. If petaflop power of currently implemented ASIC hardware is lost, the network would become so weak that it'd be vulnerable to anyone who can afford to spend $50ish-million on developing ASICs that use new protocol.

So switching is viable, but dangerous for the network until overall computational power is restored to the point where no single entity can easily amass 51% of hashrate. The 'problem' will worsen as time goes on and more SHA256 ASIC are added to network.

If this would be neccessary they would switch to a hashing algorithm for which ASICs are already out there. Yes, Litecoin could become Bitcoin's saviour in that (unlikely) scenario. It would probably also mean the (semi-) death of Litecoin because all the hashing power would leave.

Litecoin with Scrypt is kind of the backup redundancy of Bitcoin. I wish altcoins with alternate hashing algorithms be developed (instead of clones) and would gain sufficient popularity for ASICs to be developed. Redundancy's nice, but double redundancy's better

[LiteCoinGuy]

Bitcoin could switch to scryp, most scrypt hashing power goes go
to bitcoin , other scrypt alts lose most of their scrypt hash power.
The biggest danger here is for alts  IMO if sha is broken.

You are either very confused about the mining, merged mining, and the relationship between scrypt-based chains and SHA-based chains, or I was unable to make any sense of what you wrote.

is Scrypt vulnerable like sha256 though?

Neither is vulnerable...

Or, put another way, both are just as vulnerable, in that there are not any major weaknesses known for either. Probably more attention is paid to SHA-256 which is used in regular banks and a million other places. If they are equally strong, SHA-256 would probably be broken first, in that case. It is not possible to know which is stronger until both are broken, however.

good to have some Litecoins 

[wachtwoord]

Bitcoin could switch to scryp, most scrypt hashing power goes go
to bitcoin , other scrypt alts lose most of their scrypt hash power.
The biggest danger here is for alts  IMO if sha is broken.

You are either very confused about the mining, merged mining, and the relationship between scrypt-based chains and SHA-based chains, or I was unable to make any sense of what you wrote.

is Scrypt vulnerable like sha256 though?

Neither is vulnerable...

Or, put another way, both are just as vulnerable, in that there are not any major weaknesses known for either. Probably more attention is paid to SHA-256 which is used in regular banks and a million other places. If they are equally strong, SHA-256 would probably be broken first, in that case. It is not possible to know which is stronger until both are broken, however.

good to have some Litecoins  

Good to have some Scryt ASICs

[lnternet]

To answer the question, Bitcoin can change any part about it's protocol, if enough people accept that change.

To comment on cracking SHA-2, I suspect most people talking about this don't even understand what cracking a hash function means. If this were to happen however, there is a solid chance that all hashes at once get broken, and no Quark or Litecoin offers a solution.

[justusranvier]

To comment on cracking SHA-2, I suspect most people talking about this don't even understand what cracking a hash function means.

First preimage attack just means that mining gets easier. As soon as all the miners adopt the attack as part of their mining process then the difficulty just goes up and the network keeps working.

Second preimage attack is the scary one that opens up the possibility of editing history cheaply.