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It's arguably unethical to mention solidcoin and link to their PR material without at least a little word of warning: Solidcoin is not a decentralized system l

by nullc 15y ago

It's arguably unethical to mention solidcoin and link to their PR material without at least a little word of warning: Solidcoin is not a decentralized system like bitcoin. Every other block must be mined by one of several trusted parties. This has advantages and disadvantages. (Because there are only a few bitcoin clients and only one popular one bitcoin has some centralization problems too, but it's not really comparable) The solidcoin trusted parties have used this ability to change the rules of the system substantially on the users. E.g. the payout per block was recently reduced from 32 SC to 5 SC. Users could not disagree by simply refusing to "upgrade" because the trusted parties stopped issuing blocks on the old network. There is a bunch of other funny business as well. Do your research.

SkyMarshal 15y ago
>It's arguably unethical to mention solidcoin and link to their PR material without at least a little word of warning: True, my bad. I know of the scam accusations, just assumed anyone reading a Bitcoin thread in HN would have as well and that I didn't need to. But in case not... https://www.google.com/search?q=solidcoin+scam https://www.google.com/search?q=solidcoin+scam I still think their FAQ page that explains their criticisms of Bitcoin is instructive, though.
- makomk 15y ago
  Their site isn't an accurate description of Solidcoin or Bitcoin, though. There's actually a worse concentration of Solidcoins in the hands of its early adopters than Bitcoins and Solidcoin is far easier for the Government or a hacker to shutdown - all they have to do is get control of its creator's PCs. The amount given to the CPF account controlled by its creator has always been twice that stated: 10% of the value of an ordinary block, not 5%. The base reward for a block was reduced from the stated 32 Solidcoins to 5 by central fiat a month ago, which is why so many are in the hands of early adopters. The "10 trusted accounts of 1.2 million each" can actually be spent because the creator of Solidcoin designed it so he could transfer their entire contents to the CPF account he controls at will. I've already mentioned the 51% protection is deeply flawed and probably ineffective. It goes on. Some of the criticisms of Bitcoin are valid, but they've already been fixed by other less problematic clones that still never became that popular. In practice they don't actually matter that much; for example, even 2 minutes to confirm a transaction is too long for many things anyway.
makomk 15y ago
The odd thing about Solidcoin is that I'm fairly sure that its centralization doesn't actually provide the claimed security benefits. For those not familiar with Solidcoin, it has two alternating types of blocks. The odd-numbered blocks are mined through a computationally-expensive process similar to that in Bitcoin, though the Solidcoin one doesn't run as well on GPUs. The even blocks are created either by someone with more than a million Solidcoins (which no-one has) or by a node its creator controls that has a special 1.2-million-coin account. The claim is that this prevents an attacker with 51% of the compute power rewriting history and spending the same coins twice because they can't create the modified even blocks required. The trouble is that I can't see anything stopping them. The even blocks are approved by including a special transaction showing ownership of over a million coins, but there's nothing tying that transaction to the contents of that block, or the previous block, or anything except the previous transaction using that account. An attacker should just be able to copy the block-approving transactions from the original even blocks to their malicious replacements. Basically, its creator failed to grasp that if you want to validate something using a digital signature (the one proving ownership of the million coins) you need to make sure modifying that something invalidates the signature. Most of the Bitcoin clones have turned out to be inferior to Bitcoin in some way, actually. (There's some subtle issues around timestamps that'd make this attack a bit harder but I'm not intending to provide a howto guide here.)

by nullc 15y ago

SkyMarshal 15y ago

>It's arguably unethical to mention solidcoin and link to their PR material without at least a little word of warning: True, my bad. I know of the scam accusations, just assumed anyone reading a Bitcoin thread in HN would have as well and that I didn't need to. But in case not... https://www.google.com/search?q=solidcoin+scam https://www.google.com/search?q=solidcoin+scam I still think their FAQ page that explains their criticisms of Bitcoin is instructive, though.

makomk 15y ago
Their site isn't an accurate description of Solidcoin or Bitcoin, though. There's actually a worse concentration of Solidcoins in the hands of its early adopters than Bitcoins and Solidcoin is far easier for the Government or a hacker to shutdown - all they have to do is get control of its creator's PCs. The amount given to the CPF account controlled by its creator has always been twice that stated: 10% of the value of an ordinary block, not 5%. The base reward for a block was reduced from the stated 32 Solidcoins to 5 by central fiat a month ago, which is why so many are in the hands of early adopters. The "10 trusted accounts of 1.2 million each" can actually be spent because the creator of Solidcoin designed it so he could transfer their entire contents to the CPF account he controls at will. I've already mentioned the 51% protection is deeply flawed and probably ineffective. It goes on. Some of the criticisms of Bitcoin are valid, but they've already been fixed by other less problematic clones that still never became that popular. In practice they don't actually matter that much; for example, even 2 minutes to confirm a transaction is too long for many things anyway.

makomk 15y ago

The odd thing about Solidcoin is that I'm fairly sure that its centralization doesn't actually provide the claimed security benefits. For those not familiar with Solidcoin, it has two alternating types of blocks. The odd-numbered blocks are mined through a computationally-expensive process similar to that in Bitcoin, though the Solidcoin one doesn't run as well on GPUs. The even blocks are created either by someone with more than a million Solidcoins (which no-one has) or by a node its creator controls that has a special 1.2-million-coin account. The claim is that this prevents an attacker with 51% of the compute power rewriting history and spending the same coins twice because they can't create the modified even blocks required. The trouble is that I can't see anything stopping them. The even blocks are approved by including a special transaction showing ownership of over a million coins, but there's nothing tying that transaction to the contents of that block, or the previous block, or anything except the previous transaction using that account. An attacker should just be able to copy the block-approving transactions from the original even blocks to their malicious replacements. Basically, its creator failed to grasp that if you want to validate something using a digital signature (the one proving ownership of the million coins) you need to make sure modifying that something invalidates the signature. Most of the Bitcoin clones have turned out to be inferior to Bitcoin in some way, actually. (There's some subtle issues around timestamps that'd make this attack a bit harder but I'm not intending to provide a howto guide here.)