All Questions
Tagged with z-cash or cryptocurrency
49 questions with no upvoted or accepted answers
3
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0
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354
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Are digital signatures a type of zero-knowledge proof?
Are the digital signatures used in cryptocurrencies such as Bitcoin a type of zero-knowledge proof?
2
votes
1
answer
120
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Efficient NOT in set proof?
I am looking for a solution for a very specific problem, I have one, but I am not statisfied with it and it feels there must be a much more efficient way to do this.
I have a hashed value of 256 bits. ...
- 155
2
votes
0
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24
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Which channel protocol should I use to broadcast the message between parties?
I am building the Threshold Signature Scheme (TSS) based wallet. I would like to run the each party's node separately with different host. And these nodes should be able to send the messages through ...
2
votes
0
answers
814
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ECDSA Common Nonce Reuse Attack
so I recently stumbled upon this video by @bertcmiller who created two transactions with the same nonce "k". That seen I researched quite a lot of pages explaining how to recover the private ...
- 21
2
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0
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54
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What is the difference between Solution-Verification and Challenge-Response variants of Proof of Work;
Sorry if question is really dumb, I am new to crypto :(
If the client provides the solution for the PoW Challenge-Response, in my understanding, the solution of that challenge should be verified. So I ...
2
votes
0
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140
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Difference between fuzzy vault and fuzzy commitment?
https://dl.acm.org/doi/10.1145/2905055.2905118
Quoting the above paper's abstract, "Biometric cryptosystem can apply fuzzy vault, fuzzy commitment, helper data and secure sketch, whereas, ...
- 121
2
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0
answers
77
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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 ...
- 129
2
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0
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970
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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 ...
- 21
2
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0
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105
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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:
...
- 71
2
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0
answers
267
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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 ...
- 236
2
votes
0
answers
92
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Ecash - Probability of catching a user using secret splitting who duplicates the coin
For detecting double spending, secret splitting is used. If a user duplicates the coin, then there will be two different transaction items in transaction list. What is the probability of catching a ...
- 29
2
votes
1
answer
176
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Provably secure cryptography in blockchains
Do you know a blockchain that does not use at all cryptographic primitives standardized by USA or other countries? It is strange to me that the security of many cryptocurrencies is based on ciphers, ...
- 425
1
vote
0
answers
53
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How can the validity of signatures in layer-2 transactions be proven in zk-rollup?
I have many questions about the details of using zk-SNARK technology in zk-rollup：
How can the validity of signatures in layer-2 transactions be proven in zk-rollup?
In zk-rollup, is a single large ...
- 115
1
vote
0
answers
37
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Ethereum signature as xml-dsig11
This question was originally posted in https://ethereum.stackexchange.com/questions/151471/ethereum-signature-as-xml . I post it here aswell because I rarely get any response there.
I am seeking to ...
- 111
1
vote
0
answers
101
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Can we reduce the size of the XMSS signature?
As XMSS is post-quantum we can use it to secure blockchain. One of the main disadvantage of XMSS is its signature size. If we can reduce the size of the signature then we can use XMSS in the ...
1
vote
0
answers
65
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Secure permutation of $E(\mathbb{F}_q)$ as a set for an elliptic curve $E$ over a finite field $\mathbb{F}_q$
Let $E$ be an elliptic curve over a finite field $\mathbb{F}_q$. For simplicity, let the group $E(\mathbb{F}_q)$ be of prime order.
Assume that I know how to construct an efficiently computable ...
- 425
1
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0
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54
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In Zcash, how does a recipient look up which transactions belong to him/her?
For Monero, the scheme for stealth addresses is pretty straightforward. (For example: https://monero.stackexchange.com/questions/1500/what-is-a-stealth-address) However, I haven't found any details on ...
- 23
1
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0
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448
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Understanding seed phrase, private key, wallet addresses
I have a question about Cryptocurrency wallets like Metamask (soft) or Ledger (hard).
How is a 12 or 24 word seed phrase enough to show the same crypto addresses in any crypto wallet that supports the ...
- 139
1
vote
0
answers
222
views
Assuming secp256k1 curve and given fixed (but random) $h$ and $d$ values, is it possible to calculate a $k$ such that $h\equiv(k\,G)_X\,(k-d)\pmod n$?
For generator point $G$ in the secp256k1 curve, I want to find a value $k$ such that:
$$h\equiv(k\,G)_X\,(k-d)\pmod n$$
where $n$ is the group order, and $(k\,G)_X$ indicates the x-coordinate (mod n) ...
1
vote
0
answers
39
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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 ...
- 13
1
vote
0
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46
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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 ...
- 11
1
vote
0
answers
298
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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 ...
- 143
1
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0
answers
81
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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-...
- 597
1
vote
0
answers
31
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\...
- 111
1
vote
0
answers
138
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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 ...
- 11
1
vote
0
answers
57
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 ...
- 157
1
vote
0
answers
43
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 ...
- 111
1
vote
0
answers
47
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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
0
answers
223
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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 ...
- 173
1
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0
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28
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Can the precompiles in Ethereum Byzantium for pairings be used for implementation of BBS group signature verification?
I'm currently implementing a group signature verification on Ethereum and it seems that the Pairing check can only return a boolean.
According to the BBS algorithm, to validate a signature $s$, you ...
- 11
1
vote
0
answers
82
views
Can I use a blockchain to lock access to some information before a certain amount of time has passed, without relying on third-parties?
Picture the following (the example is very similar to the real scenario):
I have a physical item in possession in which I want to lock myself (don't ask [1]) from accessing it until a ...
- 111
1
vote
0
answers
121
views
Reconciling Multiple Blockchains?
I'm playing around with the idea of a blockchain where both the proof-of-work and verification steps are NP-hard. It seems the NP-hard verification step can be resolved if you allow for multiple ...
- 589
1
vote
0
answers
332
views
Can Bitcoin mining solve Graph Isomorphism-related problems?
Given a cryptographic hash $H:\{0,1\}^*\mapsto\{0,1\}^N$ and data $D\in\{0,1\}^*$, the Hashcash/Bitcoin Proof-of-Work entails finding a nonce $x$ such that $H(x\Vert D)$ begins with $d$ leading zeros, ...
- 289
1
vote
0
answers
262
views
How are attributes encoded in private keys in Attribute-Based Encryption?
I understand how private keys are generated from public keys in a setup like Bitcoin (using ECDSA).
I understand that anyone can verify they have the 'correct' private key using a digital signature ...
1
vote
0
answers
98
views
Digital cash and blind signiture: coherence between signature and serial number
My question is about the basics of the topic "creating digital cash".
At the very beginning of that topic the amount of the banknote and a serial number are the requirements for generating a ...
- 111
1
vote
0
answers
102
views
Can a LIRA system work with cjdns or other decentralized meshnets?
LIRA (Lightweight Incentivized Routing for Anonymity) is a scheme to incentivize participants in Tor to contribute resources, in particular bandwidth.
The paper talks about it being used for Tor. Can ...
0
votes
0
answers
28
views
Is it possible to convert public key to private key if anybody can decode doubling to singling?
If a point is P then,
P => Doubling operation => 2P
If anybody can reverse it, i,e
2P => Reverse Doubling => P
Will he/she be able to calculate private key from the specific public key of ...
- 125
0
votes
0
answers
59
views
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
votes
0
answers
44
views
i want to verify the following p2pkh transaction
I know to veify the p2pkh transaction we have to place the unlocking script and locking script in a stack and than evalute the stack. In such cases the the scriptpubkey_asm is of the form <OP_DUP ...
- 1
0
votes
0
answers
49
views
Practical deployments of ECC with cofactor of elliptic curves $4$ or $8$?
Are cofactor $4$ and $8$ ECC schemes widely used in practical deployments such as those in cryptocurrencies?
Can you name some practical settings where there curves are used and cryptocurrencies where ...
- 1,025
0
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0
answers
46
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The specific nature of a 51% attack - in relation to a multiple choice question that I was marked as incorrect on
In a course I'm taking the following question came up:
...
0
votes
0
answers
199
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How to get public key and bitcoin compressed address from the coordinates (x,y) generated by ECDSA?
I have my x (0xca668a8b5f71e8724aada4b5343c28702a481787855cc42228b8fff97fe94d6a) and y (0x19dd3a603a55b3d8c5f62cbe177b9b63693fb8c91d76845bafc843a7aa19ea55) coordinates generated by ecdsa with a ...
- 1
0
votes
0
answers
59
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Does the number of bits in the block nonce influence the security of the blockchain?
I know that Bitcoin uses a 32bit nonce that miners iterate over trying to hit the target number of prefixed 0's in the hash. If they run through all 2^32 combinations they then change something else ...
- 123
0
votes
0
answers
1k
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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 ...
- 145
0
votes
0
answers
62
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 ...
- 9
0
votes
0
answers
56
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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
0
votes
0
answers
148
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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 ...
- 121
-1
votes
1
answer
61
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Zero knowledge proof to validate/invalidate a claim
Have a look at the Twitter conversation below in the screenshots.
@theveveshow asks if @trader1sz has sent ETH to the girl in question? @trader1sz responds that the girl in question has indeed sent ...
- 11
-1
votes
1
answer
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