> there’s nothing to hack except from stealing private keys in which case the damage is limited to areas that this key is covering (usually very small).
On the contrary. Let's say that you institute a blockchain to trace the chain of custody for evidence (not much different than tracing the chain of custody, cough supply chain cough, for mangoes). From the creation of a piece of evidence to transferring custody between different law enforcement officials, each block on the blockchain contains the private key signatures of law enforcement agents who have testified that they have taken custody of the evidence at a certain period of time. In theory, the benefit of a blockchain here is a publicly auditable record of custody which has clear value for the admissibility of evidence at public trial. Imagine that we wave away issues of latency for the sake of argument.
With cryptocurrency, actors are motivated not to share their private keys, because sharing their private key means risking irrevocably giving away all the currency in the wallet controlled by that key. What is the similar motivation here, for law enforcement agents not to share or otherwise compromise their private keys? If one cop tells another cop "hey I need you to do me a favor and sign custody of this evidence now while not actually taking it, so I can take it somewhere else and mess with it to make sure we can for sure put this guy away," or "hey do me a favor, I'm not going to sign custody on this now, but I'll do it later on" - what prevents this from happening?
Is it supposed to be the threat of perjury? Because the courts already have a problem with testimony which has been found to be false, where perjury cases are rarely subsequently prosecuted. Put it this way - just because something is auditable, who will audit it? And how do you police domain violations which are still valid blockchain transactions?
A blockchain where you have a publicly auditable, irrevocable record is meaningless if it doesn't really mean anything for blockchain actors to "act in their own interest". In this case, undermining the private keys is everything, because that's what undermines faith in the entire blockchain.
But if you already have a trusted third party, then why do you need a blockchain? The whole point of a blockchain is to avoid the centralization of trusted third parties. At that point you might as well have a normal relational database / transactions with ACID gusrantees.
On the contrary. Let's say that you institute a blockchain to trace the chain of custody for evidence (not much different than tracing the chain of custody, cough supply chain cough, for mangoes). From the creation of a piece of evidence to transferring custody between different law enforcement officials, each block on the blockchain contains the private key signatures of law enforcement agents who have testified that they have taken custody of the evidence at a certain period of time. In theory, the benefit of a blockchain here is a publicly auditable record of custody which has clear value for the admissibility of evidence at public trial. Imagine that we wave away issues of latency for the sake of argument.
With cryptocurrency, actors are motivated not to share their private keys, because sharing their private key means risking irrevocably giving away all the currency in the wallet controlled by that key. What is the similar motivation here, for law enforcement agents not to share or otherwise compromise their private keys? If one cop tells another cop "hey I need you to do me a favor and sign custody of this evidence now while not actually taking it, so I can take it somewhere else and mess with it to make sure we can for sure put this guy away," or "hey do me a favor, I'm not going to sign custody on this now, but I'll do it later on" - what prevents this from happening?
Is it supposed to be the threat of perjury? Because the courts already have a problem with testimony which has been found to be false, where perjury cases are rarely subsequently prosecuted. Put it this way - just because something is auditable, who will audit it? And how do you police domain violations which are still valid blockchain transactions?
A blockchain where you have a publicly auditable, irrevocable record is meaningless if it doesn't really mean anything for blockchain actors to "act in their own interest". In this case, undermining the private keys is everything, because that's what undermines faith in the entire blockchain.