Questions tagged [cryptography]

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

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1answer
24 views

How can cryptocurrency replace the traditional monetary system? [closed]

If cryptocurrency takes over traditional monetary system then what are the concerns regarding user demand, scarcity and coins utility?
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18 views

Are we screwed when quantum computers start working? [duplicate]

Are there any cryptography schemes that work with Bitcoin and are quantum resistant?
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694 views

The compressed public key byte header

I've noticed that compressed public keys are always either 0x02 or 0x03, but what exactly determines whether it's 0x02 or 0x03? I can go look at the OpenSSL code to answer this, but I'm hoping someone ...
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1answer
326 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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230 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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how can I get the modular inverse of k… The nonce inverse

How can I calculate the Y axis Of the R value in the Eliptic Curve Digital Signature Algorithm (Ecdsa). The reason I said 'y' axis of the 'r' value is because I believe the y axis is the nonce used to ...
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1answer
46 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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1answer
202 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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30 views

What would a bitcoin quantum resistant address look like?

In an hypothetical future where a quantum computer is able to break the cryptography protecting the bitcoin private key, one of the solution would be to move our coins to quantum safe resistant ...
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1answer
544 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
964 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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1answer
99 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
28 views

Using xpub key derivation for user account balance?

I want to accept payments, and to keep the wallet secure I believe using a xpub key would be the correct solution. The site uses Google Login, which gives me a user id. My idea is that given the ...
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1answer
116 views

Elliptic Curve Point at Infinity

Let's take into account the Bitcoin curve. My questions are: What exactly is the "point at infinity"? Is there more than one "point at infinity" How can I identify if my EC generated x and y are the "...
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1answer
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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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1answer
823 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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Could a computer virus made less than a mb, which is sent as transaction that attacks miners? [closed]

What happens if computer virus less than a mb is sent as transaction that attacks miners?
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2answers
96 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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2answers
310 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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1answer
1k views

24 Hour price change Mean

If a currency price is showing ABC per coin and its price % is +X% or -X% then this reference is taken from which last price i.e. which point of time the price is taken
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1answer
66 views

Positive or negative private key of a bitcoin wallet?

Private key is a number. Is the question positive or negative? Is it possible to know a positive private key or negative if you only know the public key? For instance: Positive private key: 2 ...
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security of the mining algorithms litecoin vs bitcoin - scrypt vs sha256?

how is the cryptanalysis' current state on both sha256 and litecoin's scrypt? is litecoin's scrypt on a security level like sha256? by security i simply mean ways to "break"/"de-cipher" the hash ...
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1answer
49 views

How many bits of entropy is a Bitcoin address?

I've seen references to 160 bits of entropy, but I'm not sure if this is universal or just applies to the old address format.
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3answers
15k views

ECDSA: (v, r, s), what is v?

Deterministically signing a Tx with RFC6979 returns v, r, s, where r and s are the 2 values used in standard ECDSA signatures. v = 27 + (y % 2), so 27 + the parity of r, as pybitcointools indicates. ...
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BTC transfer duration

When BTC is mined, it is sent to the BTC wallet. The duration of the transaction can be up to 24h for online wallets. Is the duration faster, when transferring BTC to a “cold wallet”?
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304 views

Are BTC Private Keys evenly distributed in 256bit space?

If we assume that there are ~2^96 private keys for EACH bitcoin address (2^256-160) and we assume that in cryptography it is considered good property of every hash function if it evenly distributes ...
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1answer
64 views

I need to know about wallets in cryptocurrency, how do exchanges generate deposite address per user?

In exchanges like Binance when a user wants to deposit coins in bitcoin or in other coins, per user receives a unique public key? Do they have to generate pair key private/public key for each user in ...
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5k views

How to generate Ed25519 public key from private key using libsodium?

Not all crypto currencies are using secp256k1 technology for keypair generation and digital signatures. Curve25519 technology (frequently used to support ECDH key exchanges) is being used by a few ...
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18 views

Learning to trade iOS user friendly crypto wallet safety when stored in and transfer for trading or use to purchase or get cashed

iPhone users best crypto wallet in bitcoin currency trading and transfer for easy access to use and keep safe deposit and profits as a new and first time trading experience to the trading crypto ...
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21 views

What does Google's quantum supremacy mean to Bitcoin? [duplicate]

Recently, there has been a heated discussion on the internet about a paper published by Google on NASA's website saying that Google has achieved the so-called "quantum supremacy", which generates ...
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21 views

At what step does the private key is transformed to mnemonic phrase [duplicate]

If I am correct to make a private key you have to first generate a random 256 bit number then transform it to a WIF private key using base 58 check encode, does the mnemonic phrase is generated from ...
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63 views

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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48 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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3answers
2k 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
675 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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2answers
67 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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40 views

Is IQmining worth the investment? [closed]

I am interested in investing in crypto-contracts, is IQmining worth the investment?
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126 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
46 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
962 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
34 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
307 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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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
110 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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40 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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1answer
52 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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92 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
169 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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74 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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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 ...

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