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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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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. ...
ovanwijk's user avatar
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23 views

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 ...
thant zin tun's user avatar
2 votes
0 answers
720 views

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 ...
Robert Bahn's user avatar
2 votes
0 answers
297 views

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?
CHONG ZHAO XIAN's user avatar
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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 ...
Van Altercolt's user avatar
2 votes
0 answers
130 views

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, ...
Chirag Parmar's user avatar
2 votes
0 answers
72 views

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 ...
aleclarson's user avatar
2 votes
1 answer
515 views

How Secure Is Splitting A Bitcoin Private Key?

NOTE: This question cannot be posted to Bitcoin SE because it will not render there due to the mathematical notation. Since the mathematical notation is part of the question, this is the more ...
Crypto L Plate's user avatar
2 votes
0 answers
915 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 ...
thomas's user avatar
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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: ...
Shoaib Ahmed's user avatar
2 votes
0 answers
245 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 ...
Alex Pinto's user avatar
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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 ...
suraj's user avatar
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1 answer
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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, ...
Dimitri Koshelev's user avatar
1 vote
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39 views

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 ...
user109993's user avatar
1 vote
0 answers
36 views

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 ...
lash's user avatar
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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 ...
Anantashayana Hegde's user avatar
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63 views

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 ...
Dimitri Koshelev's user avatar
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48 views

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 ...
frt132's user avatar
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333 views

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 ...
HankCa's user avatar
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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) ...
J. Smitherson's user avatar
1 vote
0 answers
37 views

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 ...
Marcos's user avatar
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1 vote
0 answers
43 views

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 ...
Zyansheep's user avatar
1 vote
0 answers
296 views

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 ...
Noel's user avatar
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0 answers
71 views

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-...
Fiono's user avatar
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1 vote
0 answers
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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\...
porton's user avatar
  • 111
1 vote
0 answers
125 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 ...
Hatifix90's user avatar
1 vote
0 answers
56 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 ...
Patoshi パトシ's user avatar
1 vote
0 answers
41 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 ...
Ulivai's user avatar
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1 vote
0 answers
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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 ...
Black cryptographer's user avatar
1 vote
0 answers
26 views

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 ...
NathG's user avatar
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1 vote
0 answers
79 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 ...
emi's user avatar
  • 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 ...
CoryG's user avatar
  • 559
1 vote
0 answers
327 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, ...
Mark S's user avatar
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1 vote
0 answers
247 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 ...
SingularityFuture's user avatar
1 vote
0 answers
97 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 ...
StellaMaris's user avatar
1 vote
0 answers
100 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 ...
Rushikesh Papaya Nadella's user avatar
0 votes
0 answers
29 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 ...
Code's user avatar
  • 1
0 votes
0 answers
59 views

Interacting with Zksync sometimes returns an "invalid value for value.blockHash" error

I've been sometimes getting this error while interacting with zksync "invalid value.blockHash" and have been unable to find information about it elsewhere. What's curious to me is that it ...
Javier Cabrera's user avatar
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0 answers
47 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 ...
Turbo's user avatar
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0 votes
0 answers
39 views

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: ...
phoenixestant's user avatar
0 votes
0 answers
167 views

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 ...
harsh's user avatar
  • 1
0 votes
0 answers
49 views

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 ...
user491880's user avatar
0 votes
0 answers
1k views

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 ...
librehash's user avatar
  • 145
0 votes
0 answers
61 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 ...
econ's user avatar
  • 9
0 votes
0 answers
197 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 ...
THG's user avatar
  • 163
0 votes
0 answers
55 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 ...
Staizita's user avatar
0 votes
0 answers
143 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 ...
Cal-linux's user avatar
  • 121
-1 votes
1 answer
52 views

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 ...
Mogambo's user avatar
  • 11
-1 votes
1 answer
221 views

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 ...
J.Doe's user avatar
  • 151