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General Discussion / One possible attack to POS mining
« on: March 11, 2014, 03:55:11 am »
Please correct me as I'm not a native speaker and could have some wrong understandings.
Suppose I'm a bad miner, what can I do? I can
1. Exclude some transactions. This doesn't harm much as I can only make few attacks in a short period of time. In fact, you can't even tell whether I'm a bad miner excluding some transactions or I'm a good miner who hasn't received the transactions yet.
2. Roll back some transactions by rolling back some blocks. This is interesting. But how can I do that?
Well, I need some percentage of shares. Let's say I have 10% shares. As the yearly inactivity fees exist, most of shares will have (maybe much) less than 365 coin days. I can easily accumulate my coin days to 50% by not destorying the coin days for 5.x years. Using the coin days I accumulated, I can roll back a large number of blocks. The number can be really large (like 100) as I have 50% of coin days. How many confirmations do you need to feel safe for a transaction? 6, 10? I would say at least 100. Considering I can choose time when large CDD happened one day before and the diversity of the shares, the percentage of shares I need will be much less.
Suppose I'm a bad miner, what can I do? I can
1. Exclude some transactions. This doesn't harm much as I can only make few attacks in a short period of time. In fact, you can't even tell whether I'm a bad miner excluding some transactions or I'm a good miner who hasn't received the transactions yet.
2. Roll back some transactions by rolling back some blocks. This is interesting. But how can I do that?
Well, I need some percentage of shares. Let's say I have 10% shares. As the yearly inactivity fees exist, most of shares will have (maybe much) less than 365 coin days. I can easily accumulate my coin days to 50% by not destorying the coin days for 5.x years. Using the coin days I accumulated, I can roll back a large number of blocks. The number can be really large (like 100) as I have 50% of coin days. How many confirmations do you need to feel safe for a transaction? 6, 10? I would say at least 100. Considering I can choose time when large CDD happened one day before and the diversity of the shares, the percentage of shares I need will be much less.