Questions tagged [cryptography]

Concerning the broad subject of cryptography and its narrow application in Bitcoin protocol and applications.

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2answers
55 views

Is there any blockchain explorer available to track the trades of cryptocurrency exchange?

I haven't seen any decentralized exchange that provides the information of trades and can track the record of transaction history and time. I am looking forward to that exchange which can provide ...
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Can ECDH peers waste each other's time at will?

Peter Dettman notes that ECDH peers can waste each other's time at will. What does he mean? Can this be weaponized against Lightning nodes?
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15 views

Crypto Data API without Limit [on hold]

I'm looking for a Cryptocurrency price data API like coingecko that doesn't have any limit...or does anyone knows how to remove their limit?
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10 views

Who tested the tax application CryptoTax? [closed]

I just saw an ad from cryptotax.io with a sweepstake, where Cryptotax will pay your crypto taxes in the USA. You can sign up here app.cryptotax.io/register?ref=62 Has anybody ever tested this tax ...
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30 views

BIP32 HD Wallet vs HMAC vs Hashing

I've been working on a website which will be caring out various cryptographic operations. On the website users can post Ads. Each Ad has a monotonically increasing unique ID. For each Ad, I would like ...
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1answer
259 views

Mycelium Backup Restore

Is there a way I can restore my mycelium Bitcoin wallet if I have forgotten the 12-word list? I have searched everywhere and no one describes a situation like this.
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1answer
72 views

how to place a bitforex api buy order

I have read the documentation for BitForex on placing a buy order here: https://github.com/bitforexapi/API_Doc_en/wiki/Order Then after understanding that, I read the API Call Description ...
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1answer
35 views

Can a cryptocurrency be liquid while it is in its pre-sale, or even ICO

I am planning to run a Coin's ICO for several years, not interested in the gains to be made from selling out ICO in 3 days NO, but interested in using the COin to end Global Poverty as i deem fit. So ...
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3answers
1k views

Why is it impossible to modify a transaction in the blockchain?

Many pages (including Wikipedia) say that it is impossible to modify a transaction which is already in the blockchain included. But why is it so difficult?
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1answer
184 views

Does each miner in a bitcoin mining pool has a chance to win the block reward?

Suppose there is mining pool XYZ. 10 miners 1 through 10 are subscribed to it and miners have varying hash power, some have 10 GPU mining rig while others have just a single CPU running 24 hours a day ...
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1answer
648 views

Recovering the last few digits of a Litecoin private key

Is it possible to recover the last few lost digits (10) of my Litecoin wallet private key? Are there any recovery tools available? Or will I have to try and roll my own? Crucially, what crypto ...
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1answer
455 views

How do I calculate the expected shares per minute for my pool

I am currently mining Zencash in a pool, and I'd like to be able to calculate the expected shares per minute for a given pool's hashrate. Let's say the pool's hashrate is 50 KSol/s. I think that the ...
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2answers
608 views

Is it possible to discover the set of bitcoin addresses from a public key?

I'm trying to find the set of bitcoin addresses from a public key associated with a user just to analyse this user transaction. Is there any way to derive/find all the addresses that have been ...
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2answers
39 views

How can I use messengers for crypto transactions?

Is it possible to use Signal or Telegram for crypto transactions? I heard CryptoCat messenger is for such needs, but interested in using those two mentioned above.
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1answer
75 views

How to make a homomorphic preimage/payment hash with current lightning network / Bitcoin implementations?

If I remember / understand it correctly by using the mechanisms from the scriptless scripts paper we could easily create homomorphic preimages / paymenthashes. I think this would be a very desirable ...
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1answer
29 views

Is IQmining worth the investment? [closed]

I am interested in investing in crypto-contracts, is IQmining worth the investment?
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122 views

Do mining pools eliminate the need to store blockchain?

Suppose I want to design generic crypto currency miner starting from scratch . By generic I mean it can be configured to support a large number of available crypto currencies. This generic miner must ...
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1answer
43 views

Consider using Bitcoin but just heard the IRS is sending tax notices to 10k plus users

article: https://www.cnn.com/2019/07/26/tech/irs-cryptocurrency-taxes/index.html My background: Good understanding of RSA cryptography, some elliptic curve, Number Theory and I am a (real)programmer ...
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1answer
381 views

BITCOIN SCRIPT: Write the bitcoin ScriptPubKey script for a transaction that can be redeemed by anybody who supplies a square root of 1764?

Bitcoin script: For the following questions, you're free to use non-standard transactions and op codes that are currently disabled. You can use as a shorthand to represent data values pushed onto the ...
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1answer
33 views

How public-key cryptography secures bitcoin transactions from 51% attacks and Mining Attacks

I wanted to better understand how public-key cryptography avoids 51% attacks and mining attacks, also if this question is wrong please correct so that i can improve my research and provide me with ...
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2answers
300 views

To what extent does asymmetric cryptography secure bitcoin transactions?

Is there a specific attack or bug which asymmetric cryptography prevents during bitcoin transactions?
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24 views

What role does public-key cryptography play in bitcoin transaction? [duplicate]

Explain in one word and kindly tell what is it exactly that public-key cryptography does in bitcoin.
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2answers
96 views

Are there valid transactions which are impossible to mine?

Is it possible to have a bitcoin transaction T that is valid with a very generous transaction fee for which it is impossible for T to be included in the next block, or even in all subsequent blocks? ...
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2answers
188 views

Practical application of Electrum's Encrypt/Decrypt message feature?

It's pretty clear how signing a message with a Bitcoin key can be useful in proving ownership of funds. However, it's far from clear how encrypting a message with a Bitcoin key can do anything useful....
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34 views

How to integrate bitcoin address generator into website

I want to integrate a bitcoin accounts and address generator into my website, similar to those found on crypto exchanges. Users can generate addresses and have their own accounts. Is there an open ...
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0answers
36 views

Shamir SSSS how to split the example if i want to use 12 Bits instead of 11 Bits?

Shamir Mnemonics are encoded into 3 components - the Version, the Parameters, and the Shamir Share. The encoded components are concatenated together to form a Shamir Mnemonic. First Component is ...
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1answer
32 views

What's the purpose of CSHA256::Write and CSHA256::Finalize

Looking at Bitcoin Core implementation of SHA256, I noticed it was a bit different from OpenSSL's implementation. In OpenSSL, you would initialize a variable with SHA256_CTX when in Bitcoin Core it's ...
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1answer
46 views

Confused on using SHA256 code from Bitcoin Core

I was looking at Bitcoin Core code to use its SHA256 code but am confused on where I should be looking at. In bitcoin/src/crypto/sha256.h there is CSHA256 and in bitcoin/src/crypto/sha256.cpp there ...
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1answer
151 views

What are the 3 arguments called in function SHA256?

void sha256(struct sha256 *sha, const void *p, size_t size) { struct sha256_ctx ctx; sha256_init(&ctx); sha256_update(&ctx, p, size); sha256_done(&ctx, sha); } I'm trying ...
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1answer
57 views

ECDSA - why not using the cyclic additive group

As I understand things so far, the ECDSA scheme used by Bitcoin uses a group G generated by a point on the elliptic curve y^2 = x^2 + 7. Now G is a cyclic group of finite order n and is, hence, ...
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2answers
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I am just wondering what are the methods which can hide all the transactions and also able to validate transactions in an block chain?

I am new to block chain and was looking at how block chain work mainly proof of stake based . They check validity by going through all the transactions which is something concerning as everyone can ...
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4answers
175 views

cryptocurrency tax question

I have a buddy who I sent money to to buy a certain amount of Ripple. For one reason or another, I couldn't do this on my own at the time. In any case, the currency has tripled and I want him to send ...
2
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1answer
421 views

Bitcoin Core Old Wallet.dat Vulnerability

Own a wallet.dat file from 2010-2011. Yesterday I saw there was a vulnerability which is makes attacking somewhat easier if your wallet is generated by old client and I'm pretty sure my wallet is ...
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2answers
365 views

How can my private key be revealed if I use the same nonce while generating the signature?

I know it is well understood that it is not a good practice to use the same nonce while generating the signatures, but I am not getting the math right. Assume I have some UTXOs that are controlled ...
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Schnorr Fiat Shamir Transformation

In the Schnorr identity protocol, we can transform the interactive ZKP into a non-interactive one by replacing the role of the verifier (i.e. providing a random challenge value) with a hash function ...
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1answer
60 views

How to verify signature of multisig transaction

How to verify signature of multisig transaction (2-2) after it being signed by first owner? How can I understand if that owner used wrong private key => wrong signature?
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1answer
14k views

Byte array to hexadecimal and back again in JavaScript [closed]

I can generate a byte array with var myByteArray = window.crypto.getRandomValues(new Uint8Array(16)) and I get 181,143,16,173,231,56,63,149,181,185,224,124,84,230,123,36 I can then turn this into ...
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1answer
78 views

Low-s value in bitcoin signature

What are the problems related in using the "normal" ( bigger than N/2) value of the s number in transaction signature and why we use the lower one? Is it about the math behind the ecdsa?
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1answer
164 views

What's the difference between xpub and bpub?

I've seen extended public keys such as the one below xpub661MyMwAqRbcFLCsW67CH9AgprkK2MbeLbmdMiBRWb1Wamm6GjGhTFQChvPmwQGQh78MMd8Eu7CLJ7FEuwhsomD66XC74VnfgHdEx1NFSKL But now I've seen a bpub ...
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1answer
69 views

Private key generation doubt

I read that the private key pk has to be any number between 1 and n, where n is almost 10^77. Since pk' s function is practically to be used as a scalar for multiplying the generator point G, why does ...
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1answer
38 views

Are transactions with the same ScriptSig a security problem?

For instance while looking at the transaction stack of my address, tracing it to exchanges I use, I came across this: https://www.blockchain.com/btc/tx/...
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1answer
98 views

What is the current computing speed of performing an elliptic curve multiplication?

Hi I was just looking for some information on how long it would take to crack a private key in bitcoin using a brute force approach and I couldn't find a very good answer for how long it takes to ...
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2answers
86 views

The order of the generator point G used in bitcoin

Hi I was just wondering how the order of the generator point G used in bitcoin was actually calculated. From the specification listed http://www.secg.org/SEC2-Ver-1.0.pdf for secp256k1 I can see ...
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2answers
584 views

C#, How can I actively query the crypto-market?

Are there any wrappers to get the real-time crypto-currency value similar to coincap.io? Right now I am using Json to deserialize a download string from CoinMarketCap, however, the api does not ...
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1answer
55 views

Bitcoin Signatures are susceptible to quantum attacks - how exactly and with what practical impact? [duplicate]

@PieterWuille wrote in another thread: "" The hashing algorithm is probably the most quantum-resistant piece of cryptography right now in Bitcoin. Barring any specific breaks, SHA256 and RIPEMD160 ...
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1answer
111 views

How can you calculate the inverse of S component of signature, while you cannot do it in ECC to calculate private key from public key?

When verifying the signature in bitcoin, we calculate S^(-1) * hash(m) * G + S^(-1) * R * pub_key and verify that this is equal to the temporary public key. Given the same logic, why can't we use it ...
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2answers
141 views

How would one prove he is Satoshi Nakamoto if he lost his private keys

Assume you're Satoshi Nakamoto, completely, and that you've forgotten your private key/s. How do you prove that this is true, using the BTC blockchain? Is there a transaction you can make, or a ...
2
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1answer
118 views

What is so special about chacha20 stream cipher along with poly1305 for message authentication codes?

I am currently trying to dissect the low level cryptography protocols of the lightning network and I realize that in many places chacha20 is being used. I tried reading about it in the Wikipedia ...
3
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1answer
99 views

ECDSA signature with r value of 31?

occasionally on Android we are generating an ECDSA signature. This turns out to have a "r" length of 31 bytes. Is that valid? For reference here is a nice diagram outlining the ASN.1 structure of ...
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41 views

Correct breakdown of the name of secp256k1?

sec Standards for Efficient Cryptography 256 256bit prime k1 Koblitz curve no. 1 ?