All Questions
Tagged with cryptocurrency hash
36 questions
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59
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Why hashing when generating account from public key?
When producing an account out of public key it's a common approach to hash the latter multiple times (sometimes using different algos) before encoding and taking a portion of the product. Is this done ...
0
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1
answer
2k
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Finding the private key with the transaction signature [duplicate]
I have two ETH transactions (both belonging to the same address) that both have the same r value in the transaction signature, is it possible to extract the private key from it?
Details of both ...
3
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1
answer
110
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How would a malicious group of co-signers use a hash collision to sign an unintended message?
According to BIP340:
However, a major drawback of this optimization is that finding collisions in a short hash function is easy. This complicates the implementation of secure signing protocols in ...
- 31
2
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1
answer
839
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Which passphrase length is good so it's hard to break bitcoin's PBKDF2 key?
According to https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki#From_mnemonic_to_seed
To create a binary seed from the mnemonic, we use the PBKDF2 function
with a mnemonic sentence (in ...
1
vote
1
answer
783
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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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-1
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1
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263
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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 ...
- 151
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1
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94
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What hash structure is Facebook Diem using?
Some cryptocurrencies 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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1
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226
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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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1
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99
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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 ...
- 503
1
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0
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27
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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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2
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1
answer
1k
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Can Blake2 be a replacement for double SHA-256?
Is it a good choice to drop double SHA-256 and use straight Blake2 in a Bitcoin-like blockchain (more POS oriented so it's not a mining problem)?
I'm talking about Blake2 because I've read more about ...
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3
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6k
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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-...
2
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1
answer
102
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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 ...
- 123
0
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0
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62
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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 ...
- 9
1
vote
1
answer
167
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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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3
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2k
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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?
- 41
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1
answer
510
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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 ...
- 13
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1
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842
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would parallel crypto mining work
Hi everyone I was wondering would it be possible to mine a cryptocurrency like bitcoin in parallel. I have read a little about mining pools https://en.wikipedia.org/wiki/Mining_pool , But that's not ...
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-1
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1
answer
982
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Is it possible for a hash in SHA-256 to have more than 8 digits? [closed]
Is it ever possible for a hash to have more than 8 digits in SHA-256?
user69001
2
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3
answers
8k
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19 out of 24 words of BIP39 passphrase (brute-force last 5?)
I have managed to lose 5 words of my 24 word Ledger Nano S recovery phrase. I have words 1-19 but I am missing words 20-24.
I have significant holdings on the wallet so would very much like to recover ...
- 21
0
votes
1
answer
300
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Block chain and storage issues
On reading about block chain technology, it was observed that it leverages the distributed ledger technology through P2P, here integrity is ensured through hash computed by miners, and then is ...
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1
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320
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Does the One-Time Hash-based Signature Scheme render Ring Signatures useless?
On the Bitcoin community, to maintain privacy, they recommend using one-time spend addresses. CryptoNote, Monero et al. prefer Ring Signatures to maintain that privacy. There are some issues regarding ...
0
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1
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192
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How might one create a system of election by lot (sortition) that is both secure and verifiable?
I've been puzzling recently over sortition, a democratic method of selection for public office which I find very fascinating. Basically, instead of choosing candidates like Hillary Clinton or Donald ...
- 153
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1
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374
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How do I convert KECCAK-256 to FLOPS? (Ethereum)
I wanted to know how much one Ethereum KECCAK-256(hash) is in FLOPS. I know bitcoin is 12,697 flops per hash.
3
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1
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309
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How can I generate a deterministic evenly distributed random number in a blockchain
Here's the hypothetical. There's a blockchain, which for the sake of simplicity, is modelled around Bitcoin and proof-of-work.
My goal, is that for each mined block, rather than a set reward (12.5 ...
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1
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218
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Use of cryptographic hash for computing previous block hashes in blockchains
Why is the previous block hash computed using a cryptographic hash function instead of a regular hash function in Bitcoin and other blockchains?
What cryptographic hash properties (pre-image ...
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1
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234
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Someone discover two pair privkey for one address
I have a question about bitcoin privkey:
If you have TWO pair privkey(compressed and uncompressed) I wrote again TWO pair, yes i know, many person say - it is not possible, but...
And this works ...
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2
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1
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457
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Hash function and Digital Encryption Algorithm
I am familiar with the fundamentals of cryptography as well as Digital Signatures. I understand how DSA like RSA works and the fundamentals of mathematics behind digital signing and verification. I ...
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3
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1
answer
1k
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Has a SHA256 output ever been found consisting entirely of the same character?
Is it possible to have an output consisting purely of one character and does this change the entropy of that output? (If that's even possible to ascertain.)
As an example, the Bitcoin cryptocurrency ...
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27
votes
1
answer
10k
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Why hashing twice?
I'm trying to understand the Bitcoin protocol, and sometimes see instructions like this:
The TransactionId is defined by SHA256(SHA256(txbytes))
or
The hash of the public key is generated by ...
- 373
1
vote
1
answer
202
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Large Volumes of Asymmetric Encryption
First of all, I apologize in advance if I use any incorrect terminology. I am just getting my feet wet when it comes to cryptography and there is a lot to learn.
For the past 12 months, we have been ...
1
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2
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433
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Can "Approximate Hashing" work in a Proof-of-Work context?
Here is a draft of an article claimed to soon appear in a peer-reviewed conference: Matthew Vilim, Uenry Duwe, Rakesh Kumar, Approximate Bitcoin Mining.
It is proposed to simplifying a SHA-256 engine ...
- 146k
8
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1
answer
3k
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How can uniformity of hash functions (e.g. SHA-256) be proved?
In reading about the Bitcoin protocol I noticed how much its proofs-of-work apparently depend on uniformity of the SHA-256 hash function. And so presumably do many other applications.
How do ...
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4
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1
answer
399
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Complexity class of an idealised version of Bitcoin's proof-of-work (hashcash)? [closed]
To formulate this question precisely, I will define an idealized hypothetical "perfect" hash function $H(n)$ which has nice scalability properties, and will formulate a problem PERFECT HASHCASH in ...
- 149
3
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1
answer
1k
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How can a key pair be derived from an arbitrary hash?
If I correctly understand the concept of a "brain wallet" in BitCoin, you start with a passphrase, generate the hash of the passphrase, then somehow derive a public / private key from that to use as ...
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61
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3
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13k
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Hashing or encrypting twice to increase security?
Over on the bitcoin forums I asked why the bitcoin client computes SHA-256(SHA-256(x)) as its cryptographic hash for a variety of purposes. The leading theory--since the bitcoin author has disappeared-...
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