Questions tagged [cryptocurrency]

A cryptocurrency is a digital currency powered by cryptography. This tag is applicable only to Q&As about the **cryptographic mechanisms** used by a currency, not for questions about economy, usage, or acquisition of any particular currency. The later kind are unwelcome. Please note that Stackexchange has dedicated websites for Bitcoin, Ethereum, Monero, etc.

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9 views

How to calculate a valid signature? [migrated]

I am trying to create a signature that is valid on https://etherscan.io/verifySig, but it shows always that my signature is invalid: I created a random private and public key: ...
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26 views

Private Key from Extended Private Key and Public Address [closed]

Is it possible to generate a private key from a public address and an extended private key? For context: I am using C# and NBitcoin. The public address is generated from the outside via an extended ...
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Is it safe to use the same seed phrase for different cryptocurrency protocols

I want to use the same seed phrase for severl cryptocoins (Bticoin, Ethereum, Nano, etc.). I understand that each protocol has its own phrase length and possibly a different way of generating the ...
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1answer
56 views

How does hardware wallet recovery work?

I'm investigating hardware cryptocurrency wallets and am trying to understand how recovery works from a technical point of view. These wallets typically provide a 24-word "recovery seed" ...
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1answer
92 views

Are zk-STARKs really quantum resistant?

I see lots of mention that zk-STARK proofs that are being developed notably for use in blockchain networks are labelled as "quantum resistant". Many articles and reports that state this, ...
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1answer
47 views

How to pad in the SHA256 Algorithm (an example using Bitcoin Header)?

For any bitcoin block we combine various Header fields to create a string which is an input to a 2 pass SHA algorithm. The resultant hash must match with the Hash in the Block header for the Block to ...
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Crypto Economic Attacks such as Nothing At Stake and Sandwich Attack from Archive Nodes on Polkadot

Could you please advise me if there are threat vectors from archive nodes such as front running attacks, sandwich attacks and nothing at stake attacks as they are quite powerful in terms of the ...
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1answer
31 views

Related Key Attack on Schnorr Signature - Why does the challenge include $\psi = g^x$, not $y$?

The original Schnorr signature scheme suffers from a Related Key Attack (RKA) as described by Morita et al. The authors of this paper then suggest a modification to the signature algorithm to prevent ...
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24 views

Generating public/private key pair without a trusted dealer

I want to make an Ethereum wallet where I can prove no one has the private keys in one place. Basically, I was wondering whether the ECDSA signatures could be generated by multiparty computation like ...
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1answer
57 views

How to generate a random string in Python for a mission-critical application

I'm trying to figure something out, but it is difficult for me. I need to generate a fully random string in Python. My current function is attached below. I just want to know whether this is secure ...
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30 views

How are zero-knowledge proofs used in blockchains to achieve anonymity?

The idea of blockchain is clear to me - If we reach consensus and all participants have the same state, it is easy to verify transactions. But new mechanisms (like Z-Cash) allow this without the ...
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1answer
71 views

Bitcoin energy waste

Reading learnmeabitcoin I found the following how bitcoin works: The bitcoin difficulty self adjusts so that a block is solved on average in 10 minutes. Solving a block requires the miner to generate ...
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1answer
44 views

What hash structure is Facebook Diem using?

Crypto currencies use fixed values in some positions in the resulting hash, like a fixed amount of initial zeros. What fixed positions and fixed values are Facebook Diem using?
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32 views

Is it possible to provably make cryptocurrency tokens inaccessible?

Would it be possible to generate an agreed upon public key that has no corresponding private key (maybe by using the latest few block hashes of a blockchain) and then send cryptocurrency to that ...
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1answer
167 views

What are the algorithms used in Facebook's Diem algorithm?

Facebook plan a new cryptocurrency release called Diem. What algorithms are used? What output size is used for the hash function?
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1answer
81 views

is it efficient if blockchain uses double Hash algorithms $H_1$ and $H_2$?

I wonder is it efficient to use less Target condition and double hash algorithms with different target (or the same target with different Hash algorithms) and one nonce in a Block. Example Target 1 ...
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33 views

Moving a monero wallet+ node from a disk to another one [closed]

I dont know where to put this question, and the most appropriate would be here i guess, i found no criptocurrency stack, if its not here i would apreciate a link to post this I've downloaded a monero ...
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77 views

Are newer crypto currencies intrinsically more energy efficient, or just newer? [closed]

There's a lot in the news about the energy cost of Bitcoin recently. Recently Elon Musk talked about "currencies using <1% the energy per transaction of BTC". This page provides some ...
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1answer
117 views

BIP 39: If I mix my 24 seed phrase with another 24 words, will the checksum property allow an attacker to retrieve the original seed phrase?

Assume that I have a 24-word passphrase that I want to store securely but online by mixing it with another 24 words in a manner only I know. Does the checksum property somehow help an attacker to ...
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1answer
71 views

Fully understanding bitcoin transcation verifying and secp256k1

Hello fellow cryptographers. I have spent last few days trying to understand and find a way to generate secp256k1 private and public keys from scratch, but i failed. I have seen tons of videos and ...
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17 views

minimal trading amount per transaction, looking for exchange [closed]

I currently developed crypto bot with support of low transaction estimate to buy/sell. Now I am looking for exchange allowing to buy all possible pairs for under a \$1 or even less. Let's say BTC/USDT ...
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206 views

How to retrieve BIP39 seed phrase: 3 words missing of 24

I lost 3 middle words of my 24 words seed phrase for a nano ledger hardware wallet. As an example (not my real seed phrase) ...
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24 views

Can Litecoin & Bitcoin have overlapping Transaction Ids (txid) [closed]

Im currently coding my own transaction lookup page for cryptos. Since Litecoin and Bitcoin are so similar to their txid. I wanted to ask if its actually possible that these 2 currencies have ...
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2answers
137 views

What are alternatives to Proof of Work for consensus of a blockchain that doesn't contain anything of value?

For example, a distributed blockchain that would keep track of the weather. Anyone could add a weather reading, and several of these would be stored in each block, just like transactions in a ...
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1answer
113 views

Calculate private key from public key and r [closed]

I watched this video where somebody finds bitcoin wallet private keys using only the "sigR" value and the public key using a python script named "formula". How does this work and ...
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2answers
128 views

Encrypting cryptocurrency seeds for cold storage

I’d like some feedback on an encrypting algorithm. I’m not rolling my own, but even putting together well-proved pieces may create many pitfalls. (I don’t know if I'm stretching questioning in this ...
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1answer
57 views

Does applying a "PushEntropy"-function increase security of a private key?

I was just reviewing the source-code of the NBitcoin-package. As far as i can see when you create a new bitcoin-keypair Key privateKey = new Key(); (without passing ...
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Can you elaborate on pBFT for dBFT in relation to PoW and PoS consensus algorithms in layman's terms?

I've read all other related answers and googled this extensively. My intention and background in asking this question is that I am delving into cryptocurrency and blockchain technology in general. ...
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61 views

How to associate a post-quantum public key with a pre-quantum one in blockchains?

As a layperson, I'm curious if a cryptocurrency could fork to a quantum-resistant algorithm without people losing access to their wallets. Is it possible to generate a quantum-resistant public key ...
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120 views

Why wouldn't you just refer to the hash of the jpg file in the NFT storage?

This question is in reference to this tweet. It seems people are using the url of third party websites to record the reference to the content for NFTs. Why can't people just hash the jpg files for ...
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1answer
841 views

How are objects sold as NFT's ("non-fungible tokens")?

I'm familiar with "blockchain" and the theory and technology behind cryptocurrencies, tokens, and the economics behind why such things are capable of having monetary value, however I've ...
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98 views

How Secure Is Splitting A Bitcoin Private Key?

NOTE: This question cannot be posted to Bitcoin SE because it will not render there due to the mathematical notation. Since the mathematical notation is part of the question, this is the more ...
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223 views

Bitcoin Key Recovery Without Nonce Re-Use

There are a lot of questions in these forums regarding the recovery of private keys. But I'm here to postulate on something unique to a specific piece of research that I looked into recently. The ...
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1answer
51 views

Attestation of private key deletion

I recently came across an article outlining a framework for a hypothetical cryptocurrency, the article is here if you care to read the whole thing. The relevant section is the "Digital Cash" ...
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1k views

How are new coins minted in Proof of Stake systems

I've been trying to understand Proof Of Stake cryptocurrency systems, but I don't see how new coins are made using the Proof Of Stake system. My current understanding of Proof Of Stake People put up ...
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4answers
198 views

Would It Be Technically Possible To Delete Old Blocks From A Blockchain Cryptocurrency?

From what I understand, a cryptocurrency mine needs to store a copy of the entire blockchain in order to be able verify transactions, which is why most wallet owners are not miners. The more ...
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48 views

Is there any application for ZKP that prove that "I know the pre-image of Hash function"

I'm looking for any applications that using ZKP to prove that "I know the pre-image for Hash function". As far as I know, POUR operation in Zcash uses this concept but I can't find any ...
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22 views

On sub-linear ring signatures and transaction sizes

I've been reading Noether's paper on Triptych and its extension Arcturus, alongside a few others exploring sub-linear ring signature schemes. I only have one question. Each paper (RingCT3.0 and its ...
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45 views

Hash as encryption used by Monero

Monero uses a Pedersen commitment $yG + bH$ to obfuscate the value of a transaction, where $b$ is the value and $y$ is the blinding factor. For the receiver to know both variables, it uses a Diffie-...
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25 views

Cryptocurrencies: Undetectable Nothing-at-Stake - why does it matter?

The paper Formal Barriers to Longest-Chain Proof-of-Stake Protocols (Brown-Cohen, Narayanan, Psomas, Weinberg, 2018) describes an attack on Proof-of-Stake cryptocurrencies called Undetectable Nothing-...
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1answer
219 views

Can Blake2 be a replacement for double SHA-256?

My previous question was closed because it was too open-ended, so let me simplify the question: Is it a good choice to drop double SHA-256 and use straight Blake2 in a Bitcoin-like blockchain (more ...
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2answers
98 views

How can I get issuerNameHash and issuerKeyHash from PEM or DER certificates?

I need to get these values ​​from pem and der files. Is there Python and C code or openssl command for these results? Example cert in PEM format: ...
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1answer
184 views

Calculating the point on the curve during ECDSA signature verification

I'm confused as to how he got (62, 44) as an answer within this article: https://www.coindesk.com/math-behind-bitcoin
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3answers
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Is double SHA-256 the best choice for Bitcoin?

So I was just curious. I really look up to Blockchain technology and I have read that Bitcoin uses double SHA-256 for hashing. ( from what I understood, double sha256 is essentially $\operatorname{SHA-...
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2answers
102 views

Clarification questions about timestamp servers

I am reading the bitcoin white paper, and I came across the concept of timestamp servers in it. Unfortunately the description of the usage of a timestamp server leaves me with more questions. And ...
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27 views

Map many crytocurrency token IDs (2^512) into a single set of tokens IDs (2^256)

Let we have a finite (small compared to 2256) set $T$ of 257-bit numbers. Need a function $f: T \to 2^{256}$ such that it's almost of zero probability that $f(n)=f(m)$ for two different numbers $n,m\...
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2answers
434 views

Recovery Passphrase Collission for BIP-39 and BIP-44

Referring to the standards of [BIP-39] and [BIP-44]: a 'master password' consisting of 12 words uniformly selected from a 2048-word dictionary corresponds to 128 bits of entropy, that is then used as ...
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37 views

R, S, and Z values in a transaction using the Transaction ID

How can i get the R, S, and Z values and the Public Key using a transaction IDE i have? I knew of a website called 2coin.org which provided these values but now the website is no more active and it ...
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22 views

Universal Computation “measurement” using SNARKs?

If SNARKs are able to prove computations of arbitrary complexity and difficulty were executed correctly, would it be possible to use them to create a Proof of Work consensus system where ANY ...
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1answer
347 views

Can we use Bitcoin miner to break 2Key 3DES, if yes how long it takes?

As ASICs are specifically designed to generate the hash for a block of a block chain. which is much faster than other GPUs which are used to break 2key-3DES. can we use Array of ASICs to break 2key-...

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