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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Is there a metaverse/application where I can feature my 3D NFTs? [closed]

I was searching for applications where I can make my 3D NFT's available for the public, to increase the value of them, right now I am nearly at 130 3D and most of them AR comparable Skateboards but I ...
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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?
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How does Bitcoin compute the 10min average? [migrated]

the Bitcoin White Paper states on page 3: "To compensate for increasing hardware speed and varying interest in running nodes over time, the proof-of-work difficulty is determined by a moving ...
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How do I convert a JWK to an Ethereum Public & Private Key? [migrated]

I'm generating a P-256K key pair using Azure Key Vault & it returns it in JWK format. I don't know a lot about cryptography, but I need to convert this to a public & private key in the ...
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How easy is it to know how many preimages an image might have, given that there's at least one (preimage, image) pair?

I have been considering an approach to incentivize cryptocurrency miners to verify claims of quantum computational supremacy. Briefly, miners find collisions $f(x_1)=f(x_2)=y$ of some known $f:m+1\...
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Allow decryption key to be known only after a certain time [duplicate]

We have a smart contract containing encrypted data that should remain encrypted till a specified timeLimit. Then, the decryption key would be made public, for everyone to read that data. We want to ...
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Why Can't I Use an Nacl Sign Keypair for Encrypt and Decrypt Operations?

I'm aware that the difference between the NaCL sign keys vs the box keys is that the secret key that comes from the NaCL box keypair is the ...
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2 answers
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Is "The only way to confirm the absence of a transaction is to be aware of all transactions" proven?

I have read the Bitcoin paper and there is one statement that I would like to know if it is really proven ir not: The only way to confirm the absence of a transaction is to be aware of all ...
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best encryption algorithm for encrypting a string

I am making a password manager , I am new to cryptography, so , can someone tell me if this can be a good solution? 1- the user inputs the email/password 2- all the payload gets encrypted with aes@...
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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) ...
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How to ensure the security of computation and transmition on Smart Contracts?

Suppose there is a smart contract with a bidding function, and the bidder can send the bid price to the smart contract after encrypting it. When the auction is over, a trusted third party sends the ...
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Before Bitcoin what was the motivation for researching key aggregation multisig and threshold schemes?

The motivation for key aggregation multisig and threshold schemes (e.g. MuSig(2), FROST etc) in Bitcoin is obvious. Signatures are a large part of every transaction, all the nodes on the network are ...
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bitcoin public address cryptography

I was learning about bitcoin cryptography and seen some strange bitcoin public addresses like this 1Lets1xxxx1use1xxxxxxxxxxxy2EaMkJ 1fuLL1xxxx1power1xxxxxxxxxxzatvCK ...
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1 answer
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Is the Bitcoin cryptography library libsecp256k1 not susceptible to the Hertzbleed attack?

I was reading up on the recently disclosed Hertzbleed side channel attack(s). It was speculated on Twitter that the Bitcoin cryptography library libsecp256k1 is not susceptible to these attacks. ...
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Can form of elliptic curve digital signature equation be simpler?

I am curious why equations for signing/validating with ECDSA have forms they have. Is it possible to use simpler equation that have same properties. For example, this is an equation I found in the ...
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Is it theoretically possible to delegate public key generation?

Imagine the following scenario: In a given cryptocurrency, privacy should be as high as possible. For this purpose, a new account with a new address is created for every incoming transaction (the ...
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What is the general equation for determining the viability of a brute force attack on BIP-39? (Only performing access with pre-image - 12 seed words)

I'd like to be able to better define the security of a BIP-39 algorithm where I just consider the process of giving me a "seed phrase". Imagining a scenario where a hacker would try to gain ...
2 votes
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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 ...
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P256 seed problem

I'm reading up on elliptic curves and their history and it seems that people don't trust P256 seed which is defined in FIPS 186-3 on page 89 to be SEED = c49d3608 86e70493 6a6678e1 139d26b7 819f7e90 ...
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Proof of Elapsed Time (PoET)

Proof of Elapsed Time (PoET) was discovered by Intel in 2016 as a consensus mechanism primarily for permissioned blockchain networks. Importantly, we can only use this concept in permissioned ...
1 vote
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What's the best way to encrypt crypto seeds? [closed]

I would like to encrypt cryptocurrency wallet seeds (12 to 24-word passphrases) for replication and secure preservation. The seeds would be in a .txt or .rtf format before encryption. I would like to ...
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cryWhat algorithm are Trezor One and Trezor T using to sign messages? [closed]

My knowledge of cryptography is beyond shallow, and I have a problem I cannot solve. Trezor wallets have two message signing formats: "Trezor" and "Electrum". I have a method in my ...
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Question about Harden and Normal Key derivation

I am reading about Hardened and Normal child key in chapter 5 of the book "Mastering Bitcoin" by Andreas, along with this detailed thread and BIP-32. Here are some of my understanding about ...
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The simulation sound extractable NIZK

I was recently reading the paper Hawk: The Blockchain Model of Cryptography and Privacy-Preserving Smart Contracts. To prove the security, the authors assume that the NIZK used in the protocol is ...
3 votes
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two closely distanced ECDSA keys

Assume that one uses two private keys $x_1$ and $x_2$ to generate two public ECDSA keys $y_1$ and $y_2$ (e.g., used as public key for Bitcoin address). The distance between $x_1$ and $x_2$ is small (e....
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Modulo p in Elliptic Curve Cryptography

To carry out Elliptic Curve Cryptography between parties, are all elliptic curve equations considered to be in the form $\bmod p$? For example, the $secp256k1$ Bitcoin curve of the equation $y^2=x^3+7$...
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Which application protocols use elliptic curve key recovery?

Section 4.1.6 of https://www.secg.org/sec1-v2.pdf describes a technique for recovering public keys from ECDSA signatures. I guess Ethereum uses this. Like if you want to validate a particular ...
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zkSNARKS: What prevents the prover from chosing a different polynomial than the one he is expected to know

I am reading this explanation of zkSnark written by Maksym Petkus - http://www.petkus.info/papers/WhyAndHowZkSnarkWorks.pdf Here the Prover knows a polynomial of degree 3, 2 of the solutions of the ...
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Is this simple Proof of Work algorithm based on SHA256 susceptible to length extension attack?

Each block's contents are hashed into 32 bytes using $\operatorname{SHA-256}$ (call this string $a$). In order for the block to be accepted, there must be a 256bit nonce (call this string $b$) ...
14 votes
1 answer
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Why "1" in 51% attack on Blockchain network

In many sources, included Wikipedia, we read: Any pool that achieves 51% hashing power can effectively overturn network transactions, resulting in double-spending. My question is: Why do we talk ...
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Summarized steps for zero knowledge proof on a public blockchain transaction

Im triying to understand Zero knowledge proof and its applications, my first instict is a blockchain (I will use Bitcoin-like for simplicity sake) Im triying to wrap my head around it by describing ...
3 votes
1 answer
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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 ...
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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 ...
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How does not tagging hashes result in leaking the secret key if a nonce is re-used in a different scheme?

I'm reading through BIP340 and I'm having trouble understanding this part: For example, without tagged hashing a BIP340 signature could also be valid for a signature scheme where the only difference ...
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1 answer
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Is there anything stopping me from making my own NFT of an existing NFT?

I feel like I some understanding of cryptocurrencies, but what never made sense to me are NFTs. This is my current understanding of NFT's NFT's are a type of smart contract Smart contracts aren't ...
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How can I understand the math behind crypto, especially that used in blockchains / distributed ledgers?

A bit of a background about me; Computer Engineer but during my studies I didn't dive too deep into the maths, especially the crypto maths that is used to make the blockchain and cryptography work. I'...
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1 answer
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Why are public keys derived from elliptic curve cryptography (ECC) and not from hashing?

I've just started studying Bitcoin and cryptocurrencies, so I might be wrong, but so far my understanding is that public keys are derived from private keys using ECDSA, in Bitcoin's case using ...
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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, ...
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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 ...
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Let user(s) chose to mint a specific NFT from a solana collection

I have a collection of images to transform in NFTs. For that purpose I have selected to work with solana blockchain, since it is fast and cheap. I have used the following software resources: solana-...
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Literature about cryptography and programming on c++ [closed]

I'm interested in learning about cryptography and making something practical out of it - make own cryptocurrency sometime im future. I think I have good knowlegde of c++, I learned from learncpp.com ...
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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 ...
3 votes
1 answer
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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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Are there batched vector/polynomial commitment proofs with sublinear proof size for Verkle Trees?

High level goal: a Verkle tree (Merkle tree using algebraic vector commitments at each level rather than hashes) with depth d where I can prove the existence of <...
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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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1 answer
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How does hardware wallet recovery work?

I'm investigating hardware cryptocurrency wallets and am trying to understand how recovery works from a technical point of view. These wallets typically provide a 24-word "recovery seed" ...
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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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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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