Questions tagged [encryption]

Questions related to the encryption in Ethereum

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2answers
656 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
19 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 ...
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2answers
133 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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2answers
140 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 ...
0
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1answer
16 views

Data encryption

Since all data on the Blockchain is public. Presume I have multiple users submitting data which I want to hide, is there a way I can encrypt that data on the Blockchain ? Or do I have to encrypt off-...
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1answer
27 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 ...
2
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1answer
28 views

Algorithm used for symmetric key encryption by quorum

What are the symmetric key encryption techniques used by the enclave in quorum to encrypt the payload? The documentation of quorum mentions that the enclave uses a symmetric key to encrypt the payload ...
0
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1answer
45 views

Asymmetric encryption with master Key

Is there any way i can derive private and public keypairs from a Master Key? The Master Key should be able to decrypt every encryption made with the generated Keypairs. to explain a bit further i ...
5
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1answer
760 views

Size of Ethereum transaction and its signature component? [duplicate]

A couple of questions: What is the average size of an Ethereum transaction in bytes (considering say a basic value transfer case). Also, what is the size in bytes of the signature component of the ...
7
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3answers
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 ...
0
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1answer
43 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 ...
2
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1answer
86 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
580 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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1answer
282 views

Parity encryption password help

{ "id":"eca798d8-8e68-a096-a35f-174133f86e43", "version":3, "crypto": { "cipher":"aes-128-ctr", "cipherparams": { "iv":"45092c0a2032250e66a9d0bd2a33acaa" }, "ciphertext":"...
27
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2answers
9k views

How to encrypt a message with the public-key of an Ethereum address

I am writing some code in nodejs/browser. I have successfully created ethereum-addresses with the secp256k1-library. I was also able to sign and verify messages. Now I want to encrypt/decrypt a ...
4
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2answers
135 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 ...
0
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1answer
30 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
49 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?
0
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1answer
64 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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4answers
2k views

Decryption in a smart contract

I have a key pair: The data is encrypted off-chain: and it is saved into the following smart contract: contract Foo { string data; } Can I decrypt stored data on-chain, assuming I provide a ...
0
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1answer
140 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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0answers
150 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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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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4answers
739 views

“SSO-style” Login into app with web3.eth.accounts[0]

On top of the data exchanged through the Ethereum network, my app stores some extra user data in a classic DB (E.g. thumbnails, display preferences, newsletter management etc.). Doing that has led ...
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2answers
480 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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2answers
34 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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1answer
385 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 ...
2
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1answer
163 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
60 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
50 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
221 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 ...
0
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1answer
83 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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1answer
164 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
56 views

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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3answers
337 views

How to cryptographically challenge a public/private address key pair?

I know that in the Ethereum protocol, users submit transaction by cryptographically 'signing' their transactions using their private key to prove to the miners that they do own that key but without ...
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2answers
622 views

Make data from smartcontracts / events only visible for certain address/users

I Have an use case where i need : 1- My data not to be visible to the public. 2- To be able to revoke my clients/users rights to view said data from my smart contract. As anyone done that before ? ...
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0answers
118 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 ...
3
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3answers
421 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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2answers
467 views

How does Quorum prevent double spending when states are encrypted?

My understanding of Quorum is that private contracts have encrypted states hence I am confused as to how they reach consensus and prevent double spending. If each state is encrypted how can the nodes ...
3
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0answers
517 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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1answer
208 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
144 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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2answers
29 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
89 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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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 ...
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1answer
1k views

What underlying protocols are used to send packets between nodes, and how are messages encrypted?

In Ethereum, when we make transactions, which underlying protocol is used to send the packages over the network? And another question, are those messages are encrypted or not? TCP, UDP, others? All? ...
0
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1answer
274 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
172 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 ...