Questions tagged [encryption]

Questions related to the encryption in Ethereum

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Store encrypted data on-chain VS on cloud

So, I am currently doing research for a project and an interesting question was born. If I have data that I want to store encrypted, why to choose blockchain instead of a cloud provider? Since the ...
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1answer
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What is the v part of transaction signature?

If I understand correctly when we send a transaction, we send an unsigned part m and a signature consisting of v, r, s. Each node verifies the signature by checking: hash(m,r) * publicKey + r = s * ...
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Confidential data encryption on blockchain

I already built a supply chain that is able to collect product information on Ethereum. Now, that data can be confidential, but I still want to do Matrix calculations on it. I came across homomorphic ...
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1answer
34 views

Why is privateKey padded before secp256k1 signing?

I am checking how the Ethereum handles signing but I can't figure out why the math.PaddedBigBytes is necessary: func Sign(digestHash []byte, prv *ecdsa.PrivateKey) (sig []byte, err error) { if ...
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1answer
55 views

Is it possible to have multiple private keys for a single public address? [duplicate]

Since the ratio of all possible digits (please correct my math if I am wrong) of a public key versus private is: 1/79228162514264337593543950336 for public (40^16): 1 461 501 637 330 902 918 203 684 ...
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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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1answer
37 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
61 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 ...
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1answer
60 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 ...
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1answer
68 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
80 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
199 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
302 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
43 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
67 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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290 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
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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
280 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
47 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
1k 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
704 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
69 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
252 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
67 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
339 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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2answers
1k 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
219 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
60 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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182 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
563 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
73 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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1answer
231 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
158 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
97 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
44 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
117 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
901 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
3k 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
340 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
222 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
1k 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
4k 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
525 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
889 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 ...
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1answer
47 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 ...
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1answer
243 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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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 ...
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1answer
1k 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....