Questions tagged [cryptography]
Discipline or techniques employed in protecting integrity or secrecy of electronic messages by converting them into unreadable (cipher text) form.
132
questions
1
vote
1answer
31 views
Validating RSA, Ed25519 and ECDSA signatures in solidity
I am writing a contract in solidity for verifying multiple signature schemes.I found that solidity supports ECDSA, but how do I add check for RSA and Ed25519. is there any existing method/library ...
0
votes
0answers
20 views
Does the use of Non-interactive zero-knowledge proof (zk-snark) will eliminate the use of (consensus algorithm e.g. work proof)?
The privacy of the blockchain transaction is a high-demand topic these days due to some application use case requiring strict privacy protection. Some of the techniques applied to blockchain ...
3
votes
0answers
37 views
Cheap EC Operations on Unsupported Curves
I want to be able to verify signatures created by smart meters. Unfortunately, their signature algorithm doesn't use curve ALT_BN_128 but BrainpoolP256r1. I wrote this verification algorithm that ...
2
votes
2answers
80 views
How to guarantee IPFS file access based on Non Fungible Token ownership (or security)?
The file is too big to be stored on the blockchain, so it is stored on IPFS.
Only the person who owns a unique Non Fungible Token (or a Security Token) can access it.
Of course I can encrypt the file ...
0
votes
1answer
43 views
ECC scalar multiplication
I'm now trying to use scalar multiplication to recover v, but I have questions with ECC scalar multiplication.
I'm wondering if the following equations are correct.
If scalar * P = Q, then scalar * (...
0
votes
1answer
22 views
How did cryotokitties create the image of the cats?
For cryptoKitties, the images of the cats are based on gene, for example, color, curve type etc. and the image of the cat will be created, how does the image created, it is by programming running ...
2
votes
1answer
44 views
Algorand: What is the purpose of VRF
In the paper describing Algorand,two reasons are given to use verifiable random functions/cryptographic Sortion:
Sortition provides two important properties: First, given a random seed, the VRF ...
0
votes
0answers
18 views
Genesis.json Change Name from ETH to Any other [duplicate]
I want to change the name of the currency while setting up my private ethereum node, is it possible ? and if possible how can we change it ?
0
votes
0answers
12 views
if RecoverCompact succeeds, does it prove that signature is right?
eth not use VerifySignature to ensure signature,but use recovecompact func,
does it means that signature is right if recoverPlain succeeds,
// Validate the transaction sender and it's sig. Throw
// ...
2
votes
1answer
93 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 {
...
0
votes
1answer
36 views
Is S of the signature(R,S) invalid when it is larger than N/2 in Ethereum? [duplicate]
In ECDSA, both signature(r,s) and (r,-s) are valid. However, in Bitcoin, it seems that the signature fails to be verified when s-part in the signature is bigger than half of the group order from this ...
2
votes
1answer
45 views
How to get 0x0 from ecrecover?
I have a fair understanding of how ecrecover works, but I don't know how to enforce a parameter set that will deterministically return the 0x0 address. I need this in my contract tests.
Is this even ...
0
votes
1answer
143 views
How to sign a transaction using nodejs crypto?
I have a js client, web API
Js client send some data in JSON format, API prepare a transaction to be send to a smart contract, than it returns transaction raw to client to be signed locally,
and ...
1
vote
0answers
58 views
Ecrecover wrong address is returned
I'm trying to validate signed data with ecrecover.
The message is signed like this on the FE:
return this.web3.eth.personal.sign( `${nonce}`, publicAddress ).then( ( signature ) => {
...
1
vote
2answers
85 views
Why does ecrecover() take signature parameters (v,r,s) instead of the full signature?
Is there any reason ecrecover() takes the (v, r, s) signature parameters instead of the full signature, given that these can be easily computed inside the function itself?
I am asking because ...
0
votes
0answers
159 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 ...
2
votes
1answer
272 views
HD wallet public to public key derivation and non-hardened keys
This question is about hierarchical deterministic wallets and the bip32 standard which, as I understand it, allows you to deterministically derive child private/public key pairs from a master seed ...
0
votes
1answer
13 views
Is it possible to provide some manual data to create private key for the ethereum account?
We were trying to provide some manual data to create the private key if I want to create a new ethereum account using this private key.
0
votes
1answer
224 views
How to get private key with web3 v0.2.x?
web3 version 1.x has the decrypt method, which decrypts a keystore v3 JSON.
By using it the following way, I can get the private key easily:
web3.eth.accounts.decrypt(keystoreJsonV3, password);
But ...
2
votes
1answer
594 views
Understanding Ethereum signatures
I would like to understand exactly which signatures are used in the Ethereum. Here https://bitcoin.stackexchange.com/questions/12554/why-the-signature-is-always-65-13232-bytes-long it says that there ...
3
votes
2answers
4k views
How can I get a mnemonic phrase from a private key?
I have a private key for my wallet and also a keystore for it. I want to use it in MEWConnect. Is there a way to get a mnemonic phrase from a private key?
0
votes
1answer
64 views
How to define 2048-bit integers on smart contracts?
As we know solidity supports only 256-bit big integers. But for crypto primitives (sometimes) we need bigger integers, e.g. 2048-bit.
Question: how can we define 2048-bit integers on a smart contract ...
2
votes
0answers
31 views
Why is an ephemeral key used in creating a digital signature?
When creating the 'S' component of a digital signature, both the actual private key and an ephemeral private key are used.
The reasoning I've read is to ensure that the sender’s actual private key ...
3
votes
1answer
172 views
Zero Knowledge v Multi Party Computation (MPC)
I am struggling with understanding the difference between the two. From what I am putting together, they have different adversarial models, MPC adds the condition of collusion between parties i.e. ...
0
votes
3answers
226 views
how to generate mnemonics from randombytes
I am able to get the randombytes using react-native-crypto-js
const words = CryptoJS.lib.WordArray.random(32);
Is that possible to generate mnemonics using random bytes.
1
vote
1answer
54 views
Is it possible to create one-time addresses, like in monero?
In http://src.getmonero.org/library/Zero-to-Monero-1-0-0.pdf, chapter "5.2 One-time addresses", there is description of how to create them.
The problem is that Monero uses Ed25519 and Ethereum ...
2
votes
1answer
34 views
How to get two points (x, y) from an encoded pubkey?
this gives a valid address from two points;
address(uint256(keccak256(abi.encodePacked(point[0], point[1]))) & 0x00FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF);
but does that mean that if you are ...
1
vote
0answers
67 views
Ethereum geth node sync problem
I have to ethereum geth node runing as testnet syncmode=full on aws both running on same hardware and bandwidth why one is syncing very slow and other one is syncing fast?
and if I will stop the ...
0
votes
1answer
70 views
Estimation of gas in web3js 0.20
Q:- While sending only Ether One wallet to another wallet(NO SMART CONTRACT),
do we need to define the default gas limit and price?
i.e. 21000 * 3 OR 21000 * 4 OR 21000 * 5 etc
Or
I've need to use ...
3
votes
1answer
403 views
Does Ethereum support pairing operations?
I need to build an application that uses bilinear pairing operations for generating signatures. If I send a message with its signature to Ethereum, can Ethereum verify this message? Does the EVM ...
1
vote
0answers
39 views
Using ECC Brainpool curves instead of Elliptic Curves
I am exploring the use of ECC Brainpool curves instead of elliptic curves for digital signatures in Ethereum.
Is this part of the roadmap and/or anyone has experimented with the use of ECC Brainpool ...
8
votes
1answer
1k views
Why are Ethereum addresses hashes of public keys?
I understand how Ethereum addresses are generated. This thread has a great explanation: How are ethereum addresses generated?
However, what this explanation is missing is why a hash is used.
There ...
1
vote
2answers
137 views
Is data stored in string form in smart contracts publicly readable?
As a beginner, I wrote the contract below for learning purposes, aiming to create a "Safe Messaging System":
pragma solidity ^0.4.24;
contract SafeMessage {
string message;
string password;
string ...
0
votes
1answer
31 views
discover if a binary data contains Ethereum address in it?
Is there a way to guess, with some level of probability , that a 20 byte array is an Ethereum address, besides doing a query against the current StateDB and its history ?
I want to discover hidden ...
6
votes
1answer
311 views
Why are the last 20 bytes of the public key used as the address?
According to this post regarding how to derive the Ethereum address from a public key:
Take the last 40 characters / 20 bytes of this public key
(Keccak-256). Or, in other words, drop the first ...
1
vote
2answers
238 views
Can private keys change once created?
Can private keys change once the public key (address) is created?
0
votes
0answers
125 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 ...
0
votes
1answer
210 views
Solidity - Shuffle address[] Index
Hello World !
I'm trying to find a way to shuffle an array of addresses in Solidity !
Looking at Underscore / Lodash source code _.shuffle() points out a few things.
_.shuffle([1, 2, 3, 4]);
* // ...
3
votes
1answer
484 views
How can we verify BGLS aggregate signatures in Solidity?
BGLS [1] is an aggregate signature scheme by Boneh et al., that allows aggregation of signatures on n different messages from n different signers. What I want to achieve is to verify such signatures ...
0
votes
2answers
37 views
“Signing” a Smart Contract after it has been deployed
I've been tasked with writing a Smart Contract to create NFT/digital collectibles. For the most part, I'm using a standard ERC721 contract.
I will be responsible for deploying the contract. Is there ...
0
votes
1answer
162 views
Store and retrieve audio files on blockchain using hashes and authenticity matching [closed]
I am looking to store and retrieve hashes of authentic audio files on the Ethereum blockchain with the purpose of checking authenticity of these audio files in the future with the hashes stored on the ...
11
votes
2answers
800 views
What are zkSNARKs? How do they work?
From my brief exposure to the concept, zkSNARKs seems to be a form of zero-knowledge cryptography.
What can zkSNARKs bring to the table for Ethereum?
I have looked at projects like this but still ...
1
vote
2answers
524 views
Creating a new wallet mobile application for newly created crypto currency
I am doing as a Intern in Apogee Tech Global in Bangalore on Blockchain for three months.
My commitments is to learn solidity language, build smart contracts, learn Ethereum and Hyperledger.
I learnt ...
10
votes
3answers
1k views
Can ZKSnarks be implemented on the Ethereum ecosystem?
Since Zcash seems to have it's ZKSnarks implementation finished (or almost at least).
And versions of JPMorgan's Quorum had appeared with ZKsnarks implementations included see: https://www.coindesk....
14
votes
8answers
744 views
Would it be profitable enough to do a Master's degree in blockchain technologies (focused on ethereum above all)?
The end of my university studies is getting closer and closer.
I'm sure I want to do a Masters degree, but I have some doubts.
About a month ago my university released a Masters degree completely on ...
1
vote
1answer
40 views
Is there a privacy token implementation in the works for Ethereum like Monero's Tari system?
With the recent announcement of being able to have privacy type tokens on the Monero blockchain. Is there a proposal on ethereum for something similar? The usecase of having a private ERC20 would be ...
2
votes
0answers
47 views
cryptography algorithm used in ethereum [duplicate]
what algorithm does ethereum use to generate public and private key pair. If i have both the keys how can i verify the match of the key in solidity, and how much gas does it cost? is it an expensive ...
6
votes
1answer
268 views
Any understandable cryptography book/article/lecture to introduce to signatures, hashes, ECDSA etc..? [closed]
It's a long time I'm searching for cryptography lectures related to ethereum inside mechanisms, and everything I found has a high mathematical level. I'm an engineer, not a mathematics, so any article ...
2
votes
3answers
788 views
Will be a ring signature scheme possible to implement at Ethereum?
It's been quite a few days I'm wondering if a Ring Signature Scheme (like Monero (XMR) has) can be implemented on Ethereum blockchains.
As far as I know, that will be so nice in order to increase ...
1
vote
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 ...
