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Questions tagged [cryptography]

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

26 questions with no upvoted or accepted answers
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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 ...
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313 views

Can the precompiles in Byzantium for pairings be used for implementation of BLS verification?

I am looking into implementing some operations for the BLS signature scheme in Solidity, using the new precompiled contracts for pairing operations released with Byzantium. In BLS verification, to ...
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1answer
43 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 ...
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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 ...
2
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0answers
140 views

Ethereum public key recovery validation

I always thought that only the person(s) in possession of the private key to an address would be able to spend or change state for that account. But by using the recover technique rather than the ...
2
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0answers
805 views

Ethereum Dapp Account Login Protocol with Metamask

I'm building an Ethereum dapp for users to use with Metamask. We're going to have an account management system and I was trying to follow this post on how to achieve a "password-less" account system ...
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42 views

In ENS, what does the secret phrase encrypt?

The Ethereum Name Service uses a secret phrase to encrypt the bid. What is encrypted, to later be revealed during the reveal phase?
2
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0answers
434 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
57 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 ) => { ...
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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 ...
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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 ...
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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 ...
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348 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, ...
1
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1answer
432 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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1answer
100 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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53 views

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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234 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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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 ...
0
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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 * (...
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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 // ...
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157 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 ...
0
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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 ...
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44 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
224 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 ...
0
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1answer
414 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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2answers
1k views

How to calculate an Ethereum Contract's address during its creation using the Solidity language?

Now I know and have read the other thread saying that a contract's address is created deterministically via RLP encoding the creator's address and his nonce and then hashed with Keccak-256 but the ...