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.
161
questions
-1
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1answer
50 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 ...
0
votes
1answer
81 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 ...
1
vote
0answers
20 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 ...
1
vote
0answers
38 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 ...
2
votes
0answers
69 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:
...
0
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0answers
23 views
Stable coin values [migrated]
(not sure this is the right stack exchange to ask crypto-economics questions, if not please direct :) )
Why are stable coin values not exactly the value they're pegged against?
For example as of this ...
1
vote
0answers
20 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 ...
1
vote
3answers
100 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
1
vote
1answer
52 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, ...
2
votes
0answers
70 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-...
4
votes
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 ...
0
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0answers
49 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. ...
0
votes
1answer
87 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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votes
1answer
66 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 ...
1
vote
0answers
41 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 ...
2
votes
2answers
86 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 ...
2
votes
1answer
142 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?
0
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1answer
129 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 ...
1
vote
0answers
74 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 ...
2
votes
2answers
78 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 ...
1
vote
2answers
132 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 $Q = aG$...
1
vote
1answer
51 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?
1
vote
1answer
78 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 ...
2
votes
0answers
52 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], [...
1
vote
0answers
95 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 ...
3
votes
1answer
96 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 ...
1
vote
0answers
49 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 ...
3
votes
2answers
441 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 ...
1
vote
2answers
200 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 ...
0
votes
1answer
127 views
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 ...
0
votes
1answer
166 views
Bitcoin mining nonce and birthday attack
Having read the basics of mining and this about SHA256 (probabilistic?) partial preimage possible? and SAT solving - An alternative to brute force bitcoin mining, I have the following question:
...
-1
votes
1answer
116 views
Double hash question [closed]
I would like a valid Bitcoin address (derived from a private key created by rolling a pair of hexadecimal dice 32 times) to be the private key of any private / public cryptography. So if I encrypt a ...
0
votes
0answers
68 views
Modifying Elliptic Curve Parameters
For context, I was watching this bit of the video: which goes over this source code. The piece is about elliptic curve cryptography and how it works. I want to use some of this knowledge to make my ...
4
votes
1answer
80 views
Time locked cryptography using Bitcoin difficulty param and/or smart contract?
Outcome: Create a message with a count down timer. Once a top level password is entered, a countdown timer starts. Once timer expires, the message is decrypted.
Known methods: Proof of work. ...
0
votes
1answer
88 views
Is the following non-interactive zero-knowledge set membership protocol provable 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
-...
2
votes
2answers
103 views
Whats wrong with my El Gamal signature example
I'm trying to digitally sign a message m using El Gamal. So far I've been unable to verify the digital signature ive made using El Gamal.
I am using prime number, p = 8369. prime root g = 3031. ...
1
vote
1answer
45 views
Monero Ring CT sj calculation
For a university project, I am currently implementing the RingCT Ring signatures as used in Monero (before the introduction of Bulletproofs) as laid out in this paper.
To close the ring we calculate ...
-1
votes
1answer
75 views
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?
0
votes
2answers
1k views
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 ...
0
votes
0answers
43 views
Problem with e-cash system with multiple banks
Say that many banks issue electronic cash of a particular type.
If there is a malicious bank and user collusion, the malicious bank signs electronic cash for a particular user. This user then takes ...
-1
votes
2answers
225 views
How to find at least one private key from a large list of compressed public keys secp256k1
Not long ago I saw a discussion on the Bitcoin Talk forum:
https://bitcointalk.org/index.php?topic=5060735.msg50736695#msg50736695
Please give advice and working methods? Is it possible to find at ...
0
votes
1answer
78 views
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 ...
0
votes
1answer
151 views
Question on using endomorphism on secp256k1 and negative results
I have read section 3.5 (algorithm 3.7) in "Guide to Elliptic Curve Cryptography", and have been trying to implement endomorphism on secpt256k1 to speed up calculating $kP$ by changing it into 2 point ...
3
votes
2answers
435 views
Can you tell me why doing scalar multiplication of a point on a Elliptic curve over a finite field gets to a point at infinity?
I am reading Programming Bitcoin. The author said:
Another property of scalar multiplication is that at a certain multiple, we get to the point at infinity (remember, the point at infinity is the ...
1
vote
0answers
81 views
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. ...
0
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0answers
43 views
Explanation of Gallant-Lambert-Vanstone method / Endomorphism speedups [duplicate]
Can someone explain how the Gallant-Lambert-Vanstone method works (or which literature explains it)?
It is also unclear to me how the Frobenius endomorphism can be used in some cases for a speedup.
...
8
votes
2answers
2k views
Does secp256k1 have any known weaknesses?
I am wondering whether there are any properties of the curve which would technically make it easier to attack than any other curves of 256 bits in size.
I have heard that being a Koblitz curve, it ...
0
votes
0answers
93 views
Concrete examples / tutorials of how blockchain/bitcoin works
I want to understand the crypto details behind the blockchain (at least in the form that bitcoin implements it).
Can you point me to some page or documents that show the details with examples?
I ...
0
votes
1answer
320 views
The Secp256k1 curve is used in cryptocurrency. Can someone generate a private key with a different curve?
Many cryptocurrencies use Secp256k1.
Every cryptocurrency library comes with its own redundant implementation of Secp256k1, ECDSA, RIPEMD160, and SHA256. So, there can be some inconsistencies across ...
0
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0answers
31 views
Time-locked deposit protocol?
I am designing a protocol where a user A sends a time-locked deposit to user that if the user B within time t provide a proof that he exists in a location x (this may be obtained by third party like ...
