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Author Topic: Solidcoin and Coinhunter Planning 51% Attack on Litecoin  (Read 3316 times)
DeathAndTaxes
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November 01, 2011, 03:32:52 PM
 #21

True, I didn't mean completely different hashing algorithms but different SHA-2 implementations. Sisoft Sandra benchmark also uses SHA256 and the performance is completely different:
http://www.sisoftware.net/?d=qa&f=cpu_vs_gpu_crypto

Even old SHA-1 can be extensively optimized:
http://software.intel.com/en-us/articles/improving-the-performance-of-the-secure-hash-algorithm-1/

If it is just an issue of implementation then one could simply make a better CUDA miner.  The reality is that Nvidia has critical "flaws" (or maybe design decisions is better way to say it) that limit throughput on their existing hardware.

Bitcoin doesn't require any specific implementation.  Any method that produces valid SHA-256 hash is fine.

sisoft throughput is horrible which would indicate a non-optimized solution (likely masking inferiority of Nvidia GPU).

For example: HD 6970 3649 MB/s
3649 MB/s *8 = 29192 Mbps
29192 / 512 = 51.6 MH/s (512 bits in SHA-256 hash)

Bitcoin MH is actually SHA-256(SHA-256(block header))
51.6MH/s /2 = 25.8 Bitcoin MH/s

There has been a lot of work in optimizing bitcoin hashing performance.  Things like vectors, workgroup sizes, BFI, etc.  Sisoft may have simply decided on an implementation and stuck with it to provide comparable performance but their results don't indicate the peak of what AMD cards can do.


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November 01, 2011, 05:40:49 PM
 #22

True but as you state it wasn't intentional.  There is no guarantee SHA-256 will be efficient on the new 79xx series card which use a new architecutre.  Nvidia has indicated they intend to improve GPGPU integer performance so future cards may close the performance gap.  There is no way to know how well algorithms will work on future FPGA or Structured ASIC designs.
From the currently available information, it's looking like 79xx should be at least as efficient at it as previous generations of AMD cards; all the parts still seem to be there. No idea about NVidia though. FPGA and structured ASIC is more dependent on what kind of pricing you can get than anything else.

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November 01, 2011, 05:58:37 PM
 #23

The point they seem to be discussing is, with the availability of cloud computing rental services, if you want to generate a few blocks in a row on any of these ponzicoins for nefarious purposes, all you have to do is rent the horsepower to do it. However, you can just wait for the creators of any of these faulternate blockchains to let them fizzle after they pump-and-dump, and then you can be the only one mining anyway (that is, if it's not completely broken by poorly informed implementation.)

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November 01, 2011, 06:01:58 PM
 #24

True but as you state it wasn't intentional.  There is no guarantee SHA-256 will be efficient on the new 79xx series card which use a new architecutre.  Nvidia has indicated they intend to improve GPGPU integer performance so future cards may close the performance gap.  There is no way to know how well algorithms will work on future FPGA or Structured ASIC designs.
From the currently available information, it's looking like 79xx should be at least as efficient at it as previous generations of AMD cards; all the parts still seem to be there. No idea about NVidia though. FPGA and structured ASIC is more dependent on what kind of pricing you can get than anything else.

The next gen is going to be different.

AMD is keeping the 78xx series card the "same".  It is simply a die shrink.  Same GPU, more shaders, smaller, cooler, faster, cheaper.  We can make pretty good gueses as to performance per watt and performance per $.

The 79xx however is a completely new architecture (code named "graphics core next", with new instruction set, and shader design.  There are also signficant hardware changes both inside and outside the GPU.  The cards will move to higher cost but lower latency XDR2 ram for example.

How well it stacks up on both MH/w and MH/$ remains to be seen.  

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November 01, 2011, 06:03:03 PM
 #25

The point they seem to be discussing is, with the availability of cloud computing rental services, if you want to generate a few blocks in a row on any of these ponzicoins for nefarious purposes, all you have to do is rent the horsepower to do it. However, you can just wait for the creators of any of these faulternate blockchains to let them fizzle after they pump-and-dump, and then you can be the only one mining anyway (that is, if it's not completely broken by poorly informed implementation.)

How dare you to be rational when it doesn't fit douchebagexpress agenda? Roll Eyes

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November 01, 2011, 07:23:11 PM
 #26

The point they seem to be discussing is, with the availability of cloud computing rental services, if you want to generate a few blocks in a row on any of these ponzicoins for nefarious purposes, all you have to do is rent the horsepower to do it. However, you can just wait for the creators of any of these faulternate blockchains to let them fizzle after they pump-and-dump, and then you can be the only one mining anyway (that is, if it's not completely broken by poorly informed implementation.)

How dare you to be rational when it doesn't fit douchebagexpress agenda? Roll Eyes

Not sure what your point is Psy.

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November 01, 2011, 07:35:46 PM
 #27

The point they seem to be discussing is, with the availability of cloud computing rental services, if you want to generate a few blocks in a row on any of these ponzicoins for nefarious purposes, all you have to do is rent the horsepower to do it. However, you can just wait for the creators of any of these faulternate blockchains to let them fizzle after they pump-and-dump, and then you can be the only one mining anyway (that is, if it's not completely broken by poorly informed implementation.)

How dare you to be rational when it doesn't fit douchebagexpress agenda? Roll Eyes

Not sure what your point is Psy.

Then you should put your brain to work.

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November 01, 2011, 07:45:07 PM
 #28

The point they seem to be discussing is, with the availability of cloud computing rental services, if you want to generate a few blocks in a row on any of these ponzicoins for nefarious purposes, all you have to do is rent the horsepower to do it. However, you can just wait for the creators of any of these faulternate blockchains to let them fizzle after they pump-and-dump, and then you can be the only one mining anyway (that is, if it's not completely broken by poorly informed implementation.)

How dare you to be rational when it doesn't fit douchebagexpress agenda? Roll Eyes

Not sure what your point is Psy.

Then you should put your brain to work.


Far as I can tell you're implying that only BEX would rent CPU power to attack a CPU coin when there is actually an exchange, and it would be far smarter to mine once the exchanges are all closed?

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November 01, 2011, 08:07:33 PM
 #29

The point they seem to be discussing is, with the availability of cloud computing rental services, if you want to generate a few blocks in a row on any of these ponzicoins for nefarious purposes, all you have to do is rent the horsepower to do it. However, you can just wait for the creators of any of these faulternate blockchains to let them fizzle after they pump-and-dump, and then you can be the only one mining anyway (that is, if it's not completely broken by poorly informed implementation.)

How dare you to be rational when it doesn't fit douchebagexpress agenda? Roll Eyes

Not sure what your point is Psy.

Then you should put your brain to work.


Far as I can tell you're implying that only BEX would rent CPU power to attack a CPU coin when there is actually an exchange, and it would be far smarter to mine once the exchanges are all closed?

Not really... I was just implying that deepceleron was being rational and that his reasoning wasn't what BCX intended when he posted this thread with the title he used and incomplete logs that could be wrongly interpreted by people who don't pay much attention to details.
I guess I could've told you this in my previous post... sorry.


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November 01, 2011, 09:26:28 PM
 #30

The 79xx however is a completely new architecture (code named "graphics core next", with new instruction set, and shader design.  There are also signficant hardware changes both inside and outside the GPU.  The cards will move to higher cost but lower latency XDR2 ram for example.

How well it stacks up on both MH/w and MH/$ remains to be seen.  
Information about the new instruction set actually leaked ages ago, and it looks promising on paper.

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November 01, 2011, 09:48:27 PM
 #31

The 79xx however is a completely new architecture (code named "graphics core next", with new instruction set, and shader design.  There are also signficant hardware changes both inside and outside the GPU.  The cards will move to higher cost but lower latency XDR2 ram for example.

How well it stacks up on both MH/w and MH/$ remains to be seen.  
Information about the new instruction set actually leaked ages ago, and it looks promising on paper.

Please provide a cite.

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November 01, 2011, 10:11:41 PM
 #32

Just read this transcript and the only mention of them doing an attack is the title of this post.  Wish I hadn't unignored BCX to read this garbage, should have expected more lies :-(

Found this for you.

Quote
<@Ten98> but yeah, if u pay amazon money, it cost u $700 per hour to 51% LTC
...
[15:52] <@RealSolid> Ten98: right, pretty cheap to end a coin

You can pay me a dollar for finding those.  Don't worry if you keep mining ScamCoins for a week or so you might have enough (assumming the price doesn't go lower)  Grin.

If you don't/know/understand what 51% is a reference to then I recommend you just uninstall your miner and delete the ScamCoin code now.  

You are the height of dumb.... saying something costs X amount of money to achieve indicates a planned attack?  Were you dropped on your head as a child?  About a dozen or so times?


Discussing the cost and the way to do it sure sounds like a plan to me.
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November 01, 2011, 11:18:34 PM
 #33

[sigh]  Can't tell if they are just talking shit or actually making a plan to execute.

Who cares.  Bunch of retards in that camp anyway.   LTC is doing well and it sounds like they're feeling threatened to me.  So they should be Smiley

Quote
Regardless, it's further demonstration of why any reasonable people should stay as far away from RS/CH and SolidCoin as possible.

Yup.

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November 02, 2011, 12:48:18 AM
 #34

The hashrate of the litecoin network just shot up from 8 Mhash/s to 13 Mhash/s.

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November 02, 2011, 01:32:13 AM
 #35

The hashrate of the litecoin network just shot up from 8 Mhash/s to 13 Mhash/s.

That is close to the botnet scum that show up every day around this time...

The fact that it is the same time makes me think system admin.  Either rouge or authorized.  When users go home he has x thousands of machines that can hash.  Hopefully it is a rogue admin so eventually he gets caught.

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November 02, 2011, 01:34:21 AM
 #36

The hashrate of the litecoin network just shot up from 8 Mhash/s to 13 Mhash/s.

Now it is up to around 15, right around half the network.  And all of it in the "other" category, not in one of the pools.  It could be an attack, or it could be a user with a lot of cpu's.  Should make for an interesting couple of hourse.
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November 02, 2011, 01:41:41 AM
 #37



Quite interesting.

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November 02, 2011, 01:50:30 AM
 #38

That's not a 51%, that's a 66%  Grin

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November 02, 2011, 01:53:35 AM
 #39

Well the unknown wasn't '0' before hand, so much of that unknown is probably honest solo miners.

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November 02, 2011, 01:54:58 AM
 #40

Well the unknown wasn't '0' before hand, so much of that unknown is probably honest solo miners.

There's no way to find out that  Grin

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