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Questions tagged [encryption]

Questions related to the encryption in Ethereum

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1answer
16 views

How to store and encrypt Keys?

I am developing chrome extension like metamask for the private Chain. I have generated the keys and using localStorage to store the Keys. But I am not sure whether I am going correct or not for ...
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1answer
25 views

Storing encrypted data and decrypt on-chain

The idea was to store the encrypted number of tokens,and when user was sending his private key, smart-contract would decrypt the data and perform an action of sending tokens to someone else. The catch ...
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1answer
46 views

Decrypt message on-chain

I want to store some data in smart contract and then decrypt it on chain. Pseudocode: contract EncryptedData { bytes data; string public decryptedData; constructor(bytes data_) public { ...
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2answers
91 views

How to encrypt a file with multiple public address?

Can I encrypt a file with multiple public address such that each of them can decrypt the file using their private keys? Thus achieving a system to securely store file on IPFS which can be accessed by ...
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1answer
27 views

Assymetric encryption with only address

I would like to send an encrypted message to an address, without knowing their public key. If I understand ECIES correctly, in order to send an encrypted ECIES message to a party, say Bob, I need to ...
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2answers
39 views

Encryption and Decryption when transmitting data

If I was sending data to a smart contract, do I need to encrypt it before transmitting and decrypt it in the smart contract? Or is this done automatically?
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78 views

Blockchain Smart Contract EHR

I'm trying to do a miny EHR(Electronical Health Record) with Smart Contracts where I have a Pacient Contract. The problem is that in solidity everything is public, even the private variables, so I ...
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1answer
94 views

How to get decrypted transaction data in quorum?

On Quorum_Node1 I am sending a transaction with privateFor: parameter as follows: eth.sendTransaction({from: eth.accounts[0], to: "0xca84356...9a3d0ccf92b8e", data: web3.toHex('sample message for ...
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2answers
99 views

Offchain encryption in Ethereum dapp

Im wrting a dapp which holds / manages sensitive data which might need to be encrypted and decrypted and push again into chain. I know it is not safe to encrypt data in smart contract,which is why Im ...
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0answers
91 views

Encryption with Ethereum Keys for all Clients (iOS,Android,Web)

I was trying to encrypt data with Ethereum Key pairs. So far, I have managed to encrypt and decrypt data with these keys using ECIES schema on eth-crypto. Eth-crypto is a package which is built on top ...
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2answers
25 views

Storing private data that will be decrypted by a smart contract

Another private data problem! I would like to store some data in a Smart Contract, encrypted so nobody can see it upon some specific condition (time, or whatever). For instance, after one year, this ...
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2answers
258 views

Encrypt data using public key

I have three data fields in a form which will return a string. I would like to hash the value of these three strings and store it in the blockchain. However the data in these three strings is ...
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1answer
268 views

How to encrypt a string with a smart-contract private-key and decrypt that offline

Say I want to make a smart contract that is able to save secret messages (strings). The messages should be stored only in encrypted form so no one can read them, but should be decrypt-able by a couple ...
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1answer
52 views

Is Data Stored on Ethereum encrypted or only RLP encoded?

Is Data Stored on Ethereum encrypted or only RLP encoded? If data is not encrypted, is there some way to secure and encrypt it using AES encryption algorithm in cipher block chaining (CBC) or XTS mode ...
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1answer
123 views

geth inter-node communication (devp2p/rlpx) encryption

I am currently analysing the encryption mechanisms used in geth. Currently I have gathered the following information from the source code (https://github.com/ethereum/go-ethereum/blob/master/p2p/rlpx....
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1answer
35 views

what encryption does myetherwallet use?

I am trying to use the encrypted ethereum private key created by myetherwallet within my application. Everytime I need to send money, I will input my password so that my application can decrypt it and ...
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1answer
163 views

Encryption with BIP39 specification secp256k1 keys?

We are making a system where users can share files with other people but nobody should be able to figure out that all these different files belongs to same user on blockchain. these are the steps we ...
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0answers
520 views

How to use mnemonic to recovery my ethereum wallet

I use web3j to create my ethereum wallet.the Code just like down import org.web3j.crypto.Bip39Wallet; import org.web3j.crypto.Credentials; import org.web3j.crypto.ECKeyPair; import org.web3j.crypto....
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1answer
103 views

Understanding the UJO Smart Contract

I have trouble understanding the underlying mechanism for the UJO Music Portal, that helped Imogen Heap sell her album online. There is a smart contract that enables people to pay using ETH with ...
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1answer
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In ethereum if i submit any data is it stored in encrypted format? [closed]

Does Blockchain perform encryption/decryption of data?How and where is data stored in ethereum case.
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101 views

Smart Contract - Storing 113+ byte buffer in solidity

So I am using the module (eth-ecies) in npm to perform encryption of a message offchain using the public key of my reciever, and in turn I get a 113+ byte buffer after the encryption is done. Now i ...
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3answers
342 views

RE-Encrypt file in IPFS

If I have an encrypted file in IPFS with a symmetric key that I share, can I after that decrypt and re-encrypt that file with a different key in order to revoke access?
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1answer
63 views

Potential attack

I have two computers, one of them is airgapped. I had also two MEW private key, stored in the airgapped computer, I made a lot of transaction from the first private key to the second one. ...
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0answers
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key rocever from MEW locally thanks to a combo of addresses and signed transaction?

Hello I have used a private key to send the funds off line from and address to another using Myether wallet All the signed transactions made, and the addressess where the coins ...
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1answer
197 views

Private key recovering from both addresses + signed transaction?

Hello I have a problem. I have two computers, one of them is airgapped I have downloaded and runned Myetherwallet locally on an airgapped computer. On the other computer I made the on line ...
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1answer
2k views

Is it possible to derive public key from ETH address?

Goal (not asking XY question): send ETH to an address web3.js script monitoring it and acting upon transaction if msg.value > 0.1 ether then... ...encrypt a file with the public key of the msg....
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1answer
129 views

How to decrypt using Public Key

Can anyone decrypts cipher-text using Public Key? as I know we can only decrypt using private key, but in this RLPx documentation what this line means? Receiver receives the initiator handshake and ...
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1answer
74 views

Privacy-preserving smart contracts: examples, tutorial, best practices?

I want to make a proof-of-concept about privacy-preserving smart contracts. I know it's uneconomical to use encryption with Ethereum smart contracts. Are there best practices about how to do that? ...
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2answers
27 views

When creating an account with the Mist wallet, is the password a key for encrypting my wallet file or is it for something else?

In the book "Introducing Ethereum and Solidity", there is a paragraph that says: "There is no Forgot Password functionality in the Ethereum network. That’s because your password is only for this ...
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1answer
71 views

Could my private key could be reconstructed from just the ciphertext, salt and my password

Lets assume hypothetically that I have these all written down on paper somewhere. In comparison to the keystore, which I consider a JSON file that's too long, can I theoretically disregard all other ...
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2answers
443 views

A bit confused. How do I send ether using Web3j to an address (Android)

EDIT: I am using android platform I think I'm a bit confused conceptually. I would appreciate it if someone could answer these few questions for me as I'm trying to make an app so that I can be ...
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3answers
2k 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 ...
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1answer
244 views

Using smart contract to verify computation on encrypted data

I’m working on a project where all data is stored encrypted on a blockchain. There are some off-chain compute nodes that have the key to decrypt the data and perform some computation and return ...
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0answers
148 views

Can you use a smart contract to generate a symmetric key?

Let's say that I want to generate a key such that a user can use it and at the same time save the hashed key on the blockchain. My idea was to use a smart contract that could implement the Diffie-...
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2answers
2k views

What the difference between Bitcoin and Ethereum private/public keys and address?

I am trying to find a library for creating Ethereum wallets in a web environment (PHP, JS). I found Keytheremjs lib, but if use it in a browser, this tool is very slow. But I found a lot of simple PHP ...
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1answer
967 views

How do you hide data on the blockchain? [duplicate]

I am designing a system where some data needs to be hidden and the idea is to store it in an encrypted file. How can you allow nodes to interact with it through a smart contract without revealing the ...
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2answers
2k views

Ethereum wallet v3 format

Can someone explain what exactly Ethereum wallet file (v3) contains, and how it works. How exactly public-private key pair is encrypted. Why two encryption algorithms are mentioned in the file (aes-...
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0answers
318 views

OpenSSL error message when decrypting Ethereum encrypted private key

I'm trying to help a friend recover his password for an older format ethereum encrypted private key (EPK). My friend thinks he knows the password. My plan has been to use his best guess at the ...
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0answers
765 views

Smart Contract Encryption and Decryption so that only parties involved can read the content of Contract [duplicate]

I am trying to make a document sharing app after signing the NDA between 2 parties. My Smart contract saves the address of involved parties as Sender(Party1 who makes the NDA) and recipient(Party2 ...
0
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1answer
41 views

Make a variable not-visible

I am trying to create a smart contract where people can send some data as string. This data must be not-visible/not-readable by anyone until a certain date(let's say one month from now) Have I to set ...
0
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1answer
207 views

Access control of the external resource sold using a DApp?

I'm trying to create a smart contract in Solidity that the accounts can access the digital content only after paid some tokens. For example, assuming Account 1 is a buyer and Account 2 is a seller. ...
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2answers
3k views

Storing and passing encrypted data to another owner

I've been thinking about this situation for quite a while and I wonder if there is a way to solve this on the public Ethereum blockchain. User A stores some data on the blockchain, encrypted in some ...
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1answer
787 views

How to generate signature & validate signature offline w/o using web3

I just need a simple way to sign a message offline, preferably using Python or JavaScript. I don't want to have to sign in using Web3. I just want my private key to be used from a variable in the code....
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1answer
144 views

Does the private and public keys determine each other uniquely?

I wonder whether for each private/public key there correspond a unique public/private key? Of course, it must be computationally infeasible to compute the private key from the public key, but does ...
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0answers
226 views

Homomorphic Secret Sharing

Speaking of Ethereum blockchain, Is it possible to perform homomorphic secret sharing algorithmic calculations like SSS/pVSS/VSS on-chain? or should this be calculations performed off-chain
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1answer
888 views

Brute-forcing private keys

In this post by an Ethereum engineer taken from the Ethereum wiki about brute-forcing private keys, he writes: "Public keys are sized so that, absent a breakthrough in solving the discrete ...
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1answer
111 views

How do existing applications on the Ethereum blockchain enforce confidentiality of data?

How do current applications on the Ethereum blockchain enforce confidentiality of data? I know that the state of a contract is visible to any node on the network. Does this imply that there are no ...
3
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1answer
67 views

Can contracts act as decryption programs? [duplicate]

I am trying to make a contract that receives an encrypted signed transaction and stores it for later use. This transaction can only be decrypted if the specified wallet sends a transaction to this ...
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0answers
461 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. ...
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4answers
2k views

Cryptography in a smart contract

is there a way using public key cryptography (asymmetric cryptography) in a smart contract. The idea is to: 1) Encrypt some text and publish it on the block chain as a transaction. function ...