[Ethereum] Is a fully private blockchain network immutable

blockchainminingprivate-blockchainSecuritytransactions

I always hear that immutability is one of the great assets of using blockchains in banks. An auditor can come and look at the list of transactions and it will trust them because blockchains are immutable.

But consider the scenario where a bank has its own blockchain and controls all miners. How can an external party then trust anything about the blockchain. The bank could create forks as long as they want in the chain since they control all the miners, right?

Could someone please help me understand if I got something wrong ?

Best Answer

Private or permissioned? No, a private blockchain owned by one party is by definition not decentralized and therefore pointless. A central authority or a collusion of bank branch managers can anytime decide to change the history of the blockchain. Only if about >50% of blockchain nodes are owned by independent self interested parties blockchains can work.

But! This does not mean that many independent banking businesses can not use a private in the sense of permissioned blockchain to have a neutral trustworthy trading platform.

Related Solutions

Smart Contracts – Permissions and Grouping Users on the Blockchain

The easiest (and cheapest) option would probably be to use the same contract for all documents. You would have logic in your contract which enabled a party to create a document (perhaps by using a hash of the document) and specify the parties who need to sign it.
Either solution will work fine. It all depends on your architecture. If you feel like the implementation is simpler if you use a separate contract for permissions management, then do it.
You're right to think that some things are better left off of the blockchain and in a relational database. For one thing, you cannot do complex queries for data cheaply (or sometimes at all). My advice is to keep things as simple as possible. One example data structure you could use for associating doctors with patients is a simple map of patient addresses to doctor addresses:
```
// map of patients to doctors
mapping (address => address) patientsDoctors;
```
Yes, the contract will need to know the user's address, but this doesn't mean you have to know the address at the time of contract creation. For example, your contract can have one admin, assigned at contract creation, which is allowed to mutate a map of agents. Certain functions would then need to fail if msg.sender is not contained in the agents map.

Best Answer

Related Solutions

Smart Contracts – Permissions and Grouping Users on the Blockchain

Related Topic