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 latter kinds are unwelcome. Please note that Stackexchange has dedicated websites for Bitcoin, Ethereum, Monero, etc.
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DIY TRNG on an embedded system for Ethereum private key generation
I'm trying to build this Ethereum hardware wallet on a custom designed embedded system and I'm no expert. Googling around I found this Robust, low-cost, auditable random number generation
for embedded ...
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Is a truly p2p ledger (cryptocurrency) possible?
Is a truly p2p ledger possible, where there is no need for a third party (or a number of third parties) to verify ledgers.
Probably a system where the two parties who don't trust each other can verify ...
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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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Why is ethereum not using threshold signatures like dfinity for randomness? What's the drawback?
So Ethereum goes for RANDAO. The disadvantage with RANDAO is that the last validator in the commit-reveal scheme is able to hold his contributed value back and thereby influence the random outcome. ...
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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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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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Can keys from Bitcoin's Hierarchical Deterministic Wallets be correlated (reducing privacy)?
I'm trying to understand if the feature "Hierarchical Deterministic Wallets" in Bitcoin allows for complete privacy of all derived keys, and if any of those keys can be associated with each other ...
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Is the proof-of-work algorithm "Quark" insecure?
I recently found out about Quark here.
Apparently it is a proof-of-work algorithm used by several cryptocurrencies and is based on a single-level hash function, which consists of 9 different levels of ...
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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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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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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 ...
CommunityBot
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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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Is the following non-interactive zero-knowledge set membership protocol provably secure?
Given the following Zero-knowledge set-membership protocol https://infoscience.epfl.ch/record/128718/files/CCS08.pdf]. That is given in the following steps (Please refer to page 9).
The Verifier
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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 ...
CommunityBot
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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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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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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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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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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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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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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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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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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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Blockchain without cryptography
Because blockchain is decentralized, what would happen if there was no cryptography anymore to protect the blockchain? I know it would not be used anymore but why? "Hackers" could reverse transactions ...
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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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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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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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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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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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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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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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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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What are the characteristics of a quantum secure protocol?
What are the characteristics of quantum secure protocol, and does it always need to be information theoretic to be called as quantum secure? Are the current techniques used in bitcoins quantum secure?
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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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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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Broadcast encryption not using symmetric keys
Is there a common scheme for broadcast encryption that doesn't involve an exchange of a shared key? I'm aware that traditionally a common symmetrical key would be given to all parties and exchanged ...
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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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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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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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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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How secure is the Bitcoin protocol?
Are there any evidence (other than not being cracked so far) that the Bitcoin protocol is secure? "How secure" is it?
(I realize that this might not qualify as a meaningful question - feel free to ...
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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 ...
CommunityBot
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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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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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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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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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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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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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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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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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