Questions tagged [cryptography]

Discipline or techniques employed in protecting integrity or secrecy of electronic messages by converting them into unreadable (cipher text) form.

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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 ...
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155 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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I to want introduce myself to learn new and advanced technologies like AI, blockchain [closed]

I have completed 2days blockchain executive program two weeks back. Course covers high-level concept on blockchain, ethereum I have around 12+ yrs of IT experience and worked on different tools and ...
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384 views

keccak256 returns 0x000000000000000

I am using the keccak256 hashing algo to retrieve a message for a signature however I am getting the return value above. Here is the code: function adminAuthorizedSwap(string price, string quantity, ...
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1answer
461 views

ecrecover on bytes32 array elements

I am creating a contract which will allow an atomic transfer of a token with only the buyer needing to pay gas (instead of both parties). I am doing this by creating an agreement with price, quantity ...
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105 views

Verify multiple state channel signatures in one transaction

What are some ways to verify multiple state channel signatures (using ECverify) in a single transaction?
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Similar to currency-abstraction, could there be cryptography-abstraction (free market for digital signatures on a single state)?

Currency-abstraction for mining rewards was planned for Serenity, and so on, and so is out there as an idea. I thought about "signature-abstraction", so that different digital signatures could compete ...
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240 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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1k views

Is it possible to hack an ethereum account? [duplicate]

I want to know if is it possible to hack an Ethereum account?
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94 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 ...
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33 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 ...
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253 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]); * // ...
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220 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 ...
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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 ...
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1answer
44 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 ...
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261 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 ...
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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.
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298 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 ...
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58 views

Generate Public Key

I use the command: > eth.getTransaction("0xac844bd1107761fec3abe2f55bf739f0e7cc6dd1cd169a60176bfb22 9826b5a8") Where the brackets contain the hash of the successful transaction. This is what I ...
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1answer
167 views

Gas limit exceeded despite function not being complex

I am writing a function which takes in a bytes32 message and validates it against a signature (this is done without hashing to save gas). I am able to call the recover function and have it execute but ...
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671 views

R,S,V ECDSA packet signatures

I am using BouncyCastle to generate .NET core packet signatures. I want to be able to get the v value for the Ethereum signature. To these ends, and with my understanding of the meaning of the v ...
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1answer
641 views

How to call Internal functions ? or how to protect Withdraw and kill functions?

I had some function like withdraw and self-destruct functions set as internal, but I can't call them from "Mist", then I turned them to public but I set the modifier : modifier isOwner() { if (msg....
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300 views

Private ledgers on a Ethereum Blockchain Network

We are exploring one use case to connect a million customers with a bank. Since customers' transactions should be private to them, we want to understand whether we can have concept of private ledger ...
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1answer
13 views

Is there any other signature mechanism like ECDSA to verify the signed message if its tampered or not?

I would like to know if there are other signature verification methods other than ECDSA, to verify the message (eg., string, number) signed by a signer. Actually if there are alternative algorithms ...
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31 views

Verification of ECDSA signature is not valid while testing HashDice.sol

While practising on the ethereum contract HashDice.sol using truffle, the verification of the ECDSA signature is getting invalid after running the test script. describe('verify()', () => { it('...
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22 views

MITM attack in hosted wallets

i have a question: in the web wallets(hosted wallets)when user want to make a transaction and send the information to the wallet server , can a one change the information(man in the middle attack)?
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1answer
38 views

Sharing an verifiable secret message in a contract

I would like to hear your opinion on my idea to share a proof of a secret message in a contract, that users can verify later in a second phase when the message will be revealed. If the message is a ...
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28 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 ...
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1answer
62 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 * (...
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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 ?
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3answers
326 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.
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96 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 ...
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174 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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2answers
38 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 ...
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252 views

Correct way to easily call function with web3j from deployed contract

I am trying to call a function from a modified ERC20 contract and I can't manage to make it work. I am doing this with web3j from Android. I can connect to Infura. The contract is already deployed on ...
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1answer
119 views

How to prevent tampering of contract call from the web?

I have a project where users will be calling my contract from the web. I want to ensure they call the contract with exactly the parameters I give them. My strategy was to hash the combo of parameters, ...
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1answer
549 views

Create hash in c# and validate in solidity

I'm trying to build an app that will call a contract from javascript. I want the contract to validate that the parameters weren't tampered with. In order to do that, my plan was to figure out the ...
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1answer
442 views

Mist Wallet Stuck on “Connected to Node”

It got about 80% of the way through the blockchain download, then it just stopped and went to "finding peers" So I closed the wallet, restarted the PC, and now it just gets stuck on "connected to node"...
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50 views

Should investors add token address to their account to receive the ICO rewards?

I just created a token in blockchain and when I test it on Rikenby network but no tokens appear on my wallet until I added the Token address to watch list. 1- Is that normal that investors should add ...
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243 views

Encryption of keystore, keys and cryptographic library usage locations

I understand that another question posted has mentioned that the keystore has aes-128-ctr encryption: What is the strength of Mist wallet encryption? Key Derivation Function uses scrypt (where the ...

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