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Proof of Stake has yet to demonstrate as much resistence to adversarial attacks as Proof of Work. An expert in the space, Andreas Antonopoulos, speaks to this

Proof of Stake has yet to demonstrate as much resistence to adversarial attacks as Proof of Work. An expert in the space, Andreas Antonopoulos, speaks to this topic here: https://www.youtube.com/watch?v=U0T49duRt74&t=2720s https://www.youtube.com/watch?v=U0T49duRt74&t=2720s

cryptica 5y ago
There is a very strong incentive for Bitcoin proponents to push this narrative but it doesn't stand up to scrutiny. Proof of Stake is more secure than Proof of Work because it's not possible to use external resources to take control of the system. The cost of hijacking PoS is exponential, not linear. With PoW, someone who has no stake in the network could buy or rent mining hardware using fiat and take control of the network for a linear cost - This is because, unlike cryptocurrency tokens, hardware is not a scarce resource; it's always possible to produce more of it. With PoS, the only way to take control of the network is to buy more than 50% of all tokens. The cost of acquiring 50% of all tokens is non-linear since tokens become more expensive as the attacker purchases more. This is because the attacker will generate continuous demand against fixed supply of tokens; in accordance with the law of supply and demand, the price will keep increasing as they buy more tokens. Also, the incentive to follow through on the attack decreases as the attacker accumulates more tokens.
- cryptica 5y ago
  Also, most of the drawbacks that Andreas mentioned in the video are not related to PoS in general; perhaps it is more specific to certain older implementations of it. Most current PoS blockchains do provide guarantees of immutability since all transactions must be signed and the signatures must match sender public keys.
- swensel 5y ago
  This is interesting. I am curious, which PoS coin implementations do you like? If an attacker wanted to not raise the price of a coin, couldn't they use crypto OTC markets to buy large amounts while not raising the price (i've seen OTC at least marketed that way)? Aren't cryptocurrencies also only a scarce resource if they have a hard supply cap? Or do you figure in something like inflation vs coin burning to this as well? I do understand your point that the incentive to follow through on the attack decreases as the attacker accumulates more tokens, since it would be in their interest for the network to function properly at that point due to how many tokens / how much stake they have in the network. The only reason I could see the attack making financial sense at that point would be if it was a competitor who was trying to kill a competing PoS network and it was worth it to them to do so in order to promote their own network (or maybe it could be a government trying to protect their fiat currency)?
  - cryptica 5y ago
    >> This is interesting. I am curious, which PoS coin implementations do you like? I've been involved with Lisk (LSK) for several years. It's Delegated Proof of Stake though so you can use your LSK to vote for block forgers who offer a good % share of their block rewards and earn interest that way. >> If an attacker wanted to not raise the price of a coin, couldn't they use crypto OTC markets to buy large amounts while not raising the price Yes, that can happen in theory but in practice it's not feasible. In DPoS especially, whales would rarely agree to sell more than 50% of their own stake because if they did they could lose their forging delegate spot (which yields higher rewards than just voting). Because the blockchain is public, delegates all watch each other's on-chain activity and they can lose votes if they try to sell too many tokens (doesn't matter if it's OTC or exchange). >> Aren't cryptocurrencies also only a scarce resource if they have a hard supply cap? Or do you figure in something like inflation vs coin burning to this as well? If there is inflation, it doesn't affect the security of the blockchain because the attacker must acquire 50% of all tokens in any case. The more tokens there are in total, the more tokens the attacker needs to buy to get to 50%. >> The only reason I could see the attack making financial sense at that point would be if it was a competitor who was trying to kill a competing PoS network and it was worth it to them to do so in order to promote their own network Early days of any blockchain are always more risky. That said, the early days of most PoW blockchains are even more precarious than those of PoS. This is because with PoW, the community has no say over who can start forging blocks on its new blockchain (anyone who owns some crypto mining hardware can compete to produce blocks on potentially any PoW blockchain). If just a tiny % of Bitcoin's miners were temporarily repurposed (e.g. minor software changes) to mine any new PoW blockchain, those miners could easily take over the new blockchain and create any transaction they want. With PoS, in the early days, the community gets to decide who will receive the initial tokens; so outsiders cannot highjack the network unless then find a way to buy more than 50% of the tokens from existing token holders.

cryptica 5y ago

There is a very strong incentive for Bitcoin proponents to push this narrative but it doesn't stand up to scrutiny. Proof of Stake is more secure than Proof of Work because it's not possible to use external resources to take control of the system. The cost of hijacking PoS is exponential, not linear. With PoW, someone who has no stake in the network could buy or rent mining hardware using fiat and take control of the network for a linear cost - This is because, unlike cryptocurrency tokens, hardware is not a scarce resource; it's always possible to produce more of it. With PoS, the only way to take control of the network is to buy more than 50% of all tokens. The cost of acquiring 50% of all tokens is non-linear since tokens become more expensive as the attacker purchases more. This is because the attacker will generate continuous demand against fixed supply of tokens; in accordance with the law of supply and demand, the price will keep increasing as they buy more tokens. Also, the incentive to follow through on the attack decreases as the attacker accumulates more tokens.

cryptica 5y ago
Also, most of the drawbacks that Andreas mentioned in the video are not related to PoS in general; perhaps it is more specific to certain older implementations of it. Most current PoS blockchains do provide guarantees of immutability since all transactions must be signed and the signatures must match sender public keys.
swensel 5y ago
This is interesting. I am curious, which PoS coin implementations do you like? If an attacker wanted to not raise the price of a coin, couldn't they use crypto OTC markets to buy large amounts while not raising the price (i've seen OTC at least marketed that way)? Aren't cryptocurrencies also only a scarce resource if they have a hard supply cap? Or do you figure in something like inflation vs coin burning to this as well? I do understand your point that the incentive to follow through on the attack decreases as the attacker accumulates more tokens, since it would be in their interest for the network to function properly at that point due to how many tokens / how much stake they have in the network. The only reason I could see the attack making financial sense at that point would be if it was a competitor who was trying to kill a competing PoS network and it was worth it to them to do so in order to promote their own network (or maybe it could be a government trying to protect their fiat currency)?
- cryptica 5y ago
  >> This is interesting. I am curious, which PoS coin implementations do you like? I've been involved with Lisk (LSK) for several years. It's Delegated Proof of Stake though so you can use your LSK to vote for block forgers who offer a good % share of their block rewards and earn interest that way. >> If an attacker wanted to not raise the price of a coin, couldn't they use crypto OTC markets to buy large amounts while not raising the price Yes, that can happen in theory but in practice it's not feasible. In DPoS especially, whales would rarely agree to sell more than 50% of their own stake because if they did they could lose their forging delegate spot (which yields higher rewards than just voting). Because the blockchain is public, delegates all watch each other's on-chain activity and they can lose votes if they try to sell too many tokens (doesn't matter if it's OTC or exchange). >> Aren't cryptocurrencies also only a scarce resource if they have a hard supply cap? Or do you figure in something like inflation vs coin burning to this as well? If there is inflation, it doesn't affect the security of the blockchain because the attacker must acquire 50% of all tokens in any case. The more tokens there are in total, the more tokens the attacker needs to buy to get to 50%. >> The only reason I could see the attack making financial sense at that point would be if it was a competitor who was trying to kill a competing PoS network and it was worth it to them to do so in order to promote their own network Early days of any blockchain are always more risky. That said, the early days of most PoW blockchains are even more precarious than those of PoS. This is because with PoW, the community has no say over who can start forging blocks on its new blockchain (anyone who owns some crypto mining hardware can compete to produce blocks on potentially any PoW blockchain). If just a tiny % of Bitcoin's miners were temporarily repurposed (e.g. minor software changes) to mine any new PoW blockchain, those miners could easily take over the new blockchain and create any transaction they want. With PoS, in the early days, the community gets to decide who will receive the initial tokens; so outsiders cannot highjack the network unless then find a way to buy more than 50% of the tokens from existing token holders.