Author Topic: Does publishing feeds too frequently harm the network?(喂价太快会伤害网络吗?)  (Read 4188 times)

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Offline theoretical

The "provocative" post [1] raises an interesting point.  Does publishing feeds with high frequency harm the network?

The idea is if everyone's publishing price feeds very frequently, the cost to manipulate the feed is small -- the attacker can simply dump BTS on exchanges, causing a dip in the price feed, then sell much larger BitUSD holdings into margin calls at artificially high prices.  A relatively small manipulation -- only needing to clear out the order book depth immediately available on the exchanges -- can be amplified into a much larger manipulation -- margin calls to force covering at inflated prices by the entire short float.

OTOH if you have a random update interval (with some known expected value), the attack is much more expensive.  E.g. if average feed publish interval is 8 hours, then (assuming all delegates are online and honestly reporting prices) it takes 4 hours to update the median feed, so the attacker would have to sustain his dump for 4 hours, making it more expensive.

Also, "reactive" publishing -- publishing after a sudden price movement -- would also have a downside, it would mean a lot of delegates would update at the moment the attack commences.

I think we should consider the possibility that feed updates need to be done more slowly so that traders have time to move funds into / across exchanges and force any dump to break through the all the actively trading capital in the ecosystem, not just whatever happened to be immediately available on the exchange(s) when the dump occurred.

The main cost is that if there's a news event at a single discrete point in time that causes a quick price change, margin positions may not immediately be liquidated and the price would have time to fall further before the feed caught up and the positions started to unwind.

Thoughts?

[1] https://bitsharestalk.org/index.php?topic=13865.0

Translation:
总的来说,是讨论受托人喂价是否应该频繁和即时的问题。如果受托人喂价是频繁的,那么在外盘就很容易通过砸穿外盘来带动内盘的实时连环反应。但如果受托人喂价是随机的、不及时的、受托人之间频率相差很大的话,那么在外盘砸盘就需要持续很久才能达到这个目的,也增大了恶意砸盘的成本。

楼主还感觉,如果喂价变化速度慢点,那么就有利于搬砖、套利等行为,从而制约恶意砸盘。

不过,楼主认为这个方法可能有一个缺陷,如果价格变化得太快,空头仓位不能及时被平仓,等缓慢节奏的喂价改变后,这时候空头仓位的抵押品可能就没有那么充足了。 大家有啥想法?
« Last Edit: February 02, 2015, 06:01:24 pm by cn-members »
BTS- theoretical / PTS- PZxpdC8RqWsdU3pVJeobZY7JFKVPfNpy5z / BTC- 1NfGejohzoVGffAD1CnCRgo9vApjCU2viY / the delegate formerly known as drltc / Nothing said on these forums is intended to be legally binding / All opinions are my own unless otherwise noted / Take action due to my posts at your own risk