Linked Questions

0 votes
1 answer
1k views

Verifying if a user actually owns the address [duplicate]

Web3js frontend with Vue, .NET Core with Nethereum at the back. The key target for this functionality is to sign a message at the frontend, send the signature and the address to the backend to ...
Nicholas's user avatar
  • 101
4 votes
0 answers
195 views

How to encrypt messages to an account owner with the Ethereum public key? [duplicate]

As I understand it, an Ethereum account is a public/private key pair. Is it possible to encrypt a message with the public key (how?) that only the account holder can decrypt it with his private key? ...
Christoph2806's user avatar
2 votes
0 answers
51 views

Sending private information to account owner [duplicate]

I'd like to send an encrypted message, outside the blockchain, to an account owner who has previously interacted with a contract and whose public key is now known. Is there yet any existing ...
Mikko Ohtamaa's user avatar
70 votes
5 answers
64k views

Get public key of any ethereum account

Can I somehow get the public key of an ethereum account knowing just the corresponding ethereum address (e.g. 0x54dbb737eac5007103e729e9ab7ce64a6850a310)?
Edward Ruchevits's user avatar
7 votes
1 answer
4k views

Current methods to send encrypted messages from contracts

I am trying to understand if there currently exists a method to send a message from a contract to another contract or a private address? What would the Solidity code for this look like? Perhaps events ...
k-zar's user avatar
  • 442
4 votes
3 answers
7k views

How to encrypt a message using only the public key from web3.eth.sign?

I retrieve the public key of a users account using Web3 as follows: web3.eth.sign(web3.eth.accounts[0], web3.sha3('test'), function (err, signature) { var sigtest = signature ...
ZhouW's user avatar
  • 1,358
9 votes
1 answer
6k views

What's a recommended way to pass secret in Solidity?

Hi I'm an Ethereum noob just trying something out. I have a quick question for the community here about passing secrets in Solidity. Since, we can only control who can change state variables in ...
Pii's user avatar
  • 580
4 votes
3 answers
1k views

Storing data pointer on blockchain

How can I store user data on smart contract without exposing it to other nodes to read ? I read somewhere that you can store data pointers instead of data on contract and use it for offline data ...
Rachna Chadha's user avatar
3 votes
1 answer
1k views

How to store a private data in ethereum

My use case is the following: I want to use ethereum to track devices, and device owners. This is easy to do using ethereum and smart contract. But I want to store a secret associated with the device....
tomsoft's user avatar
  • 168
1 vote
1 answer
1k views

How to create a contract with private data accessible to a particular user?

I want to create a contract that stores encrypted data that is accessible only a selected user on the blockchain. A ideal scenario would be to encrypt the data using the user's public key, such that ...
Omkar Khair's user avatar
0 votes
1 answer
1k views

How can I encrypt a file using an ethereum public address and decrypt it with the private address?

The expected outcome is very simple: Users will send their ERC20s to a smart contract. Depending on the amount, each user will get a file specifically created for them. I want to distribute that ...
Iulian's user avatar
  • 640
2 votes
1 answer
807 views

How to decrypt an ECIES encrypted message using a geth account and JSON-RPC protocol?

A geth node is managing an Ethereum account, having the control over its private key at keystore folder. I guess to keep it safe, best practices are letting geth by its own perform all operations that ...
Juan Ignacio Pérez Sacristán's user avatar
3 votes
0 answers
785 views

"Invalid DER format public key" error trying to use bitcore-ecies for encryption with Ethereum keys

I started this blog for generation of the keys. Which I'm able to follow successfully. My generated Private, public key and the address is mentioned in the testIdentity variable in the code below. ...
Vixon's user avatar
  • 557