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Author Topic: Cheap way to attack blockchain  (Read 27798 times)
hetecon
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December 01, 2015, 04:29:47 PM
 #121

So this will be able to have a fix but requires convincing of the largest pools.

Yes. Miners are able to immediately require higher fees for these transactions or to ignore these transactions when they create blocks.

To me this means it is not a problem with bitcoin concept, but a problem with certain versions of the wallet/mining wallet systems.
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mezzomix
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December 01, 2015, 05:45:31 PM
 #122

It's not limited to the miners. I operate several relay nodes and patched my nodes to reject those transactions before they are stored in the mempool. With this change my nodes no longer forward transactions with a high number of SIGOPS.

With a mining node I would not reject those transactions but require a high fee.
hetecon
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December 01, 2015, 05:47:44 PM
 #123

It's not limited to the miners. I operate several relay nodes and patched my nodes to reject those transactions before they are stored in the mempool. With this change my nodes no longer forward transactions with a high number of SIGOPS.

With a mining node I would not reject those transactions but require a high fee.


Do you have a github commit for me to look at?
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December 01, 2015, 06:21:22 PM
 #124

Do you have a github commit for me to look at?
this link have been posted a number of times in this topic
https://github.com/bitcoin/bitcoin/pull/7081
hetecon
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December 01, 2015, 06:35:32 PM
 #125

Do you have a github commit for me to look at?
this link have been posted a number of times in this topic
https://github.com/bitcoin/bitcoin/pull/7081

much simpler then expected :0
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December 01, 2015, 10:18:59 PM
 #126

Do you have a github commit for me to look at?
this link have been posted a number of times in this topic
https://github.com/bitcoin/bitcoin/pull/7081

I use a hard coded limit but this pull request will be more flexible.
basil00
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December 02, 2015, 04:03:04 AM
 #127

This attack can be made more effective by exploiting this.  That is, instead of a vanilla OP_RETURN you use the script:

Code:
   OP_RETURN OP_CHECKMULTISIG

This counts as a extra 20 sigOps.  This bug is fixed in 0.12.0 (by making this script non-standard).
hetecon
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December 04, 2015, 06:19:51 AM
 #128

This attack can be made more effective by exploiting this.  That is, instead of a vanilla OP_RETURN you use the script:

Code:
   OP_RETURN OP_CHECKMULTISIG

This counts as a extra 20 sigOps.  This bug is fixed in 0.12.0 (by making this script non-standard).

interesting thing to see here. i trying to get this script lang down lol
DuddlyDoRight
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December 16, 2015, 02:58:58 AM
 #129

Problem is fees are already arbritrary creating usability issues.. Add more add more problems..

Oh cool I just put my savings in to bitcoin!! Hey what happen to 0.005% of it or why does it get no confirmations.. No refunds wtf?

Bitcoin is suppose to be a currency not a quick-profit-scheme for people who buy the hardware or learn the internals..

I have faith that one day this forum will get threads where people won't just repeat their previous posts or what others have already stated in the same thread. Also that people will stop acting like BTC is toy-money and start holding vendors accountable. Naive? Maybe.
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December 17, 2015, 03:00:01 AM
 #130

WOW,The day bitcoin starts blacklisting will be the end.

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DuddlyDoRight
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December 20, 2015, 01:17:01 AM
 #131

WOW,The day bitcoin starts blacklisting will be the end.

Never blacklist. Just whitelist. I'm not sure why basic reputation scares people here so bad..

There is nothing built in to the block-chain that says a bank is a bank and again, BTC is a currency not a profit system..

I have faith that one day this forum will get threads where people won't just repeat their previous posts or what others have already stated in the same thread. Also that people will stop acting like BTC is toy-money and start holding vendors accountable. Naive? Maybe.
amaclin
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December 20, 2015, 01:24:06 AM
 #132

WOW,The day bitcoin starts blacklisting will be the end.

https://gitlab.com/bitcoin/luke-jr-bitcoin/commit/5f8e7180c4b34d5f46c61a6dd2242f4249b5f79a
oakpacific
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January 26, 2016, 10:25:29 PM
 #133

Isn't transaction selection already a NP-hard knapsack problem? What kind of a beast it will become if we throw....computational complexity itself into the mix? "Hmmm, let me  estimate  if I am gonna spend more time processing these transactions or more time doing the estimation..." Roll Eyes

https://tlsnotary.org/ Fraud proofing decentralized fiat-Bitcoin trading.
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January 31, 2016, 01:27:25 PM
 #134

This attack can be made more effective by exploiting this.  That is, instead of a vanilla OP_RETURN you use the script:

Code:
   OP_RETURN OP_CHECKMULTISIG

This counts as a extra 20 sigOps.  This bug is fixed in 0.12.0 (by making this script non-standard).

Will have a read of this.
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