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. Please note that Stackexchange has dedicated websites for Bitcoin, Ethereum, Monero, etc.

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37 views

Is is possible to set up bots for BitCoin faucet websites? [closed]

I was looking at the BitCoin faucets and they all require you to fill in information repeatedly to earn a very small amount of BitCoin (like 10 satoshis). The amount earned is definitely not worth the ...
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1answer
60 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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Can I recover the ETH wallet I created using Geth after reinstalling Windows? [closed]

I installed Geth and ran some mining activities, using the nanopool network. When I built the wallet I mined with, I followed the directions here: https://geth.ethereum.org/docs/interface/managing-...
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3answers
180 views

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
56 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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23 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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14 views

Why does Bitcoin use ECDSA, instead of plain old hashing, to secure transaction outputs? [migrated]

For example, let’s say I pick a random secret and hash it. Now, in the hypothetical hash-based scheme, my hash effectively replaces my public-key hash, and my random secret effectively replaces my ...
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2answers
86 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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17 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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16 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
306 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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1answer
77 views

Cryptographic limit to total accounts in secp256k1

Factoring in birth day attacks and all that, with 256-bit elliptic curve cryptography, lets take secp256k1 as example that Bitcoin uses, what is the maximum number of accounts that are secure? It isn'...
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1answer
57 views

Why shouldn't cryptocurrency hash algorythms, resist side channel attack?

2015's Argon2 publication suggests that cryptocurrency hashing like password hashing on backend servers should not be subject to side-channel attack: Argon2d is optimized for settings where the ...
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21 views

Probability of finding a valid block when cryptocurrency mining

Today I learned that for BTC, the probability of a hash being valid is approximately 1/(D*2^32), whereas D denotes to the difficulty. I was wondering if this is ...
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1answer
45 views

How can I prove ownership of hardware wallet?

I’m applying for a mortgage loan and I recently made a large deposit into my bank account from crypto stored on a ledger hardware wallet . I sent the funds to Coinbase where I converted to usd and ...
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49 views

Cryptography that lets you conceal a secret, but also alerts others of the exposure of the concealed secret?

Is there such a cryptography where I can prove that someone decrypted an encrypted string? Say I wanted to attach a Bitcoin private key in some type of digital container, but in order to open this ...
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2answers
124 views

Is RSA secure enough to protect bitcoin private keys? [duplicate]

Suppose my very trusting friend has a bitcoin private key with a large balance (let's say $1B USD worth of Bitcoin) and wishes to keep a backup copy with me as a trustee. He doesn't want to transfer ...
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32 views

Suggestion on dynamically changing hash algorithms for blockchain

First of all excuse me for my inexperience on the topic (I am new to cryptography). I am currently studying for my Master thesis and am am looking for hash function on which I can modify them so thy ...
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36 views

Bitcoin ECDSA signature

I am trying to use the ecdsaSign function in ecdsa.c of https://github.com/kvhnuke/Ethereum-Arduino/tree/master/Ethereum-Arduino/libs which is based on the files in the repo https://github.com/...
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1answer
71 views

Why can't miners accept lower fees [closed]

From what I understand about crypto such as Ethereum or Bitcoin, Miners are verifying transactions and being awarded for doing so. Right now Ethereum has some really high gas prices. (Price of ...
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98 views

How do you verify that an address is related to a private key

This is my first post. My interest for cryptography is exclusively motivated by cryptocurrencies. My question is: If I generate some keys, how do I actually verify that the address is indeed ...
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1answer
87 views

Destroy bitcoin-qt curve parameters real or not? [closed]

Good night everybody. Is it real destroy all EC parameters in bitcoin client ? If remove "+7" and replace base point to (0,0 or 1,1)in algorithm then making a new address or public key, ...
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1answer
57 views

Is it safe to store mnemonic seed in the email if I change random 2 words?

If I store 12 word seed in the email like gmail and my phone as well but change 3rd and 7th words in the seed for example with other bip-39 words and remember it, would that be safe? I can't think of ...
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1answer
114 views

To what extent would Bitcoin be private without address reuse?

Let's say Bitcoin had these rules from the start: An address with balance cannot more receive money An address must use all its money in one transaction This would prevent address re-use. To what ...
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24 views

What guarantees that a mined block will be accepted on the network? (Blockchain)

What ensures that a mined block will be accepted on the network? I mean, if I mine a valid block in the blockchain, and I transmit it to the network, what is the incentive to people accept it? Doesn't ...
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48 views

What is the maths behind Bitcoin's BIP32?

I've read about BIP32 key derivation functions. I'm trying to understand how, given a secp256k1 key pair, that "child" public keys may be generated from just the public key, and the ...
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77 views

How hard is it to link a hardened BIP32 child public key to it's parent public key?

The BIP32 spec says this in the security section: ...
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22 views

Size of messages in timing attack on RSA Montgomery

I'm codin' timing attack on RSA Montgomery which compares two sets ( the first one includes those which need a reduction in contrary to the second one ). But I got troubles with the Montgomery ...
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3answers
633 views

How can i check if a public key match with a private key

Is there a way to check, (with openssl command for example), if a given public key match with a private key ? Thanks
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1answer
64 views

Could multicollisions be used to mine large amounts of cryptocurrency?

I'm reading about hash functions at the moment, and in the book I'm reading there's a section on multicollisions. Specifically, using a 2-collision to find $2^N$ collisions in $N2^N$ time. If, ...
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1answer
94 views

Creating a private cryptocurrency without trusted setup

I am interested in creating a cryptocurrency which keeps the sender, the receiver and the amount private and does not require a trusted setup. I have already read the Zerocash protocol but It uses zk-...
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3answers
1k views

Why do people criticize and mistrust the e-voting based block chain?

I am planning to implement an e-voting system based on hyperledger fabric blockchain, however, I came across many criticisms from well-known security experts like Josh Benaloh and others. The problem ...
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133 views

Comparisons of ECDSA, EdDSA and BLS Signatures in Blockchain: Pros and Cons

As we know, the most used digital scheme in Blockchain is ECDSA. For now, more and more blockchain projects, I've noticed, are considering substituting EdDSA and BLS signature scheme as the new one. ...
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1answer
90 views

Why mining bitcoins is difficult?

As I understand to obtain a Golden Block is to finding a nonce that matches a hash lower than a given target, as shown in this research-gate article. And here is a "py" kernel: Bitcoin mining python (...
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1answer
75 views

Is it possible to depict the bitcoin mining problem as a TSP-metric problem?

I wonder if someone can represent the blockchain encryption problem (used to mine bitcoins) as a TSP-metric problem (where TSP = Traveling-Salesman Problem). Any approach or intuition of the idea to ...
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0answers
58 views

Is the proof-of-work algorithm “Quark” insecure?

I recently found out about Quark here: https://en.bitcoinwiki.org/wiki/Quark_Algorithm Apparently it is a proof-of-work algorithm used by several cryptocurrencies and is based on a single-level hash ...
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2answers
101 views

Doesn't d6 to binary for 256-bit bitcoin private key generation produce biased results?

If the mapping table looks like: 1: 000 2: 001 3: 010 4: 011 5: 100 6: 101 Then you are guaranteed that your key will never have a chain of 4 or more 1s, much fewer chains of 3 ones than would ...
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2answers
281 views

What's the difference between a hash chain, transaction chain and a blockchain?

Can anyone explain to me what the difference is between a hash chain, transaction chain and a blockchain?
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1answer
196 views

Can we retrieve his private key using his public key in ECC?

A paper wallet is the name given to an obsolete and unsafe method of storing bitcoin which was popular between 2011 and 2016. It works by having a single private key and bitcoin address, being printed ...
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88 views

ZK Proof that a blinded message (for a blind signature) contains a certain value

I am toying with eCash systems and blind signatures, and I started with Chaum's original formulation. In particular, I'm using this formulation from this link: User ...
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2answers
116 views

How blockchain system manages it's memory limit for nodes?

As we know, in the blockchain system every node has historical data that contains all previous transactions to maintain the integrity and approve the future transaction. What if blockchain is ...
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2answers
171 views

How does this formula work $(aG + bG) = (a + b) G$ in ECDSA?

Please explain how does this formula $(aG + bG) = (a + b) G$ work in ECDSA? According to the source: $a$ and $b$ are different private keys Suppose $a = 3$ $b = 4$ then the public key is $Q = aG$...
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1answer
54 views

Cryptography in virtual currencies [closed]

Apart from bitcoins and altcoins, are there any other virtual currencies (like game currencies, gift cards or coupons) that include cryptography in their algorithm?
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1answer
135 views

What if the hash code of the genesis block (first block in the block chain) is changed?

If so, what would happen? And if not, what are some limitations to it? The reason I am asking is because I just started getting into the cryptocurrency and am very interested in the cybersecurity ...
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0answers
62 views

Post-quantum aggregate / multi signatures

Are there any practical post-quantum aggregate / multi signatures? Currently, the aggregate / multi signature schemes seem to be limited to pre-quantum elliptic curve assumptions only, e.g., [BDN18], [...
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0answers
119 views

Proof of membership on a merkle tree

I read the zcash paper recently. But I have been puzzled by a question. How did the authors prove that the coin commitment appears as a leaf of a Merkle tree with root rt? Apparently, the authors ...
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1answer
117 views

How does ZK-snark work in zcash?

For a public one-way function $f()$, we can use zero proof to prove I know some secret $x$, such that the output of $x$ is a specific number $y$. However, in zcash, I need to prove that I have some ...
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51 views

Is the 51% attack the only technical reason no country will ever adopt Bitcoin as a state currency? [closed]

Is the 51% attack the only technical reason no country will adopt Bitcoin as a state currency? Let's suppose a country with a GDP size less than 300 Billion USD adopt the Bitcoin as an official ...
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2answers
675 views

Would SHA-256(SHA-256(x)) produce collisions?

Was reviewing some Bitcoin public-key hash literature and the use of RIPEMD-160 and the SHA-256 as below: RIPEMD160(SHA256(ECDSA_publicKey)) The Proof-of-work ...
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2answers
290 views

How does ECDSA signature verify work in EOS and ETH/BTC, compare to standard (on text book I mean)

I have been studing ECDSA signature/verify for a while. By my understanding: the standard ECDSA signature/verify process (which we find on text book) are like below: - A sender combines message and ...