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7

All data can be seen by external parties. The solution to this is to send the data encrypted to the smart contract, such that to retrieve it, your private key would be required. Hope this helps.


5

All the data in the Blockchain is public. The "public" keyword creates a getter for the variable, (a function that return the value). When you make it private the getter is not created but you can access the storage of the contract. web3 allows you to read the storage using: web3.getStorageAt(address, position) see this for more info Hope this helps


3

Yes, since all the info in the blockchain is public, anybody (who knows enough about how data is stored internally) can read the value in the variable.


2

I think your best bet at this point in time would be to use zkSNARKs which has significantly more support overall through the ecosystem, although zkSNARKs operations aren't cheap. While searching for ethereum ring signatures, the only recent implementation I could find was a the following reddit thread, although development appears to have stopped https://...


2

Sorry. It's not possible. On the real ethereum network you're just some random account with no actual funds trying to pass bad cheques. It won't work. Hope it helps.


2

This is absolutely true so far. There is no info about how to setup PoS Casper private network. But here are some useful links: Installing Casper on Ubuntu Casper Pyethapp Development Environment Containers Casper repository By the way if you need to setup a PoS private network for work, Casper might not be the best option, because the implementation of ...


2

I only want the person who has access to the private key of the public key it was encrypted with to see the data. Is there a possible way to do it Yes, you need to encrypt it before you send the data to the blockchain. Everything in the blockchain, including transactions, is public. So if you send the data in plaintext, anyone can see it. At the moment I ...


2

You can try something like this: contract KYCPurchase { uint public price = 2 ether; address owner; constructor() public{ owner = msg.sender } modifier _ownerOnly(){ require(msg.sender == owner); } struct Company { string registeredNumber; string companyName; } mapping (address =...


1

Is it absolutely required to be in the first block? With some modifications to Geth you could theoretically apply the state changes at genesis. This would mean every node that has the genesis file you specified would have the contracts predeployed, similar to what Rob was referring to with Pegasys.


1

Yes, someone can see private values. Private simply tells contracts what they can and cannot read. People can extract the data from the private value. Please see this thread. And also in the api for solidity it states: "Everything you use in a smart contract is publicly visible, even local variables and state variables marked private."


1

This is what I do: File NodeInit.bat (run once, or whenever you want to delete the DB and start from zero): rd /s /q data\geth call "C:\Program Files\Geth\geth.exe" --datadir=.\data init .\genesis.json File NodeOpen.bat (run whenever you want to start the network): cmd /c "title geth & "C:\Program Files\Geth\geth.exe"" ^ --networkid=100 ...


1

Everything that happens inside the blockchain is public information. So all the data you have is readable for anyone who knows how to access it. The only way for you to hide some information is by encrypting it before it reaches blockchain (so somewhere in your backend). This way nobody can interpret the data without the right encryption key, but this also ...


1

According to documentation (haven't practice for a while) --rpcaddr value HTTP-RPC server listening interface (default: "localhost") You need to pass the address on witch one your rpc endpoint must be listenning. If I remember well, it corresponds to the IP address authorized to send commands. By default, it is your localhost. To allow everyone, ...


1

I have done this multpiple times and also created a tutorial, see here to do it in javascript: https://github.com/pubkey/eth-crypto/blob/master/tutorials/encrypted-message.md


1

Unless you find JSON formated text file with keys such as "id", "cipher", "ciphertext", "salt"...etc, I don't think you would be able to recover. If you find it, you will be able to extract it via not just metamask but also other tools, assuming you know the correct password. You need either that or your mnemonic. Password is just missing information to ...


1

Assuming you have the source code for the contract in question, it's a two-step process: Determine, from the source code, the location(s) in storage that you're interested in. Call the eth_getStorageAt JSON-RPC method (perhaps multiple times) to retrieve the data. Two of my blog posts might help: Understanding Ethereum Smart Contract Storage explains how ...


1

These are just test ethers. They have no real value.


1

Wherever language you want. I made this code in Python by myself: https://github.com/Grana69/GranaBlockChain Its simple but was written with a Blockchain logic.


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