Questions tagged [cryptography]

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

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Crypto Transfer [closed]

I wanted to know, if I have altcoin in one exchange and wanted to transfer in another exchange, but that altcoin is not bought in target exchange. Is it possible? i.e: I have ADA in Binance exchange ...
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How to change the field of the elliptic curve to the new value N while keeping the default Secp256k1 parameters?

I want to change the margin of the elliptic curve to the new N value, while doing so I want to keep the parameters Standard G-point Generator Secp256k1 that is, I want to replace: N = ...
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Import 256 bit private key

Can I import a 256 bit private key in a Wallet (binary format)? Or do I have to convert it in another format?
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Crypto Account hacked

12 words password has been hacked and lost all the money in crpto account. Anyways to recover the money ? Please please help!
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Bitcoin users limit

How bitcoin handle users limit if only 4000 transactions in every 10 minutes ? Let's say I transfer 2 bitcoin to Anuj account then how much time maximum it will take to reflect in Anuj's account and ...
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Is that proved that breaking ECDSA as hard as solving ECDLP?

Is that proved that breaking ECDSA (Elliptic Curve Digital Signature Algorithm) as hard as solving ECDLP(Elliptic Curve Discrete Logarithm Problem)?
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How do bitcoin verifies block hash after new hash have been submitted by Miners? [duplicate]

I want to know how at the end of Bitcoin server block hashes are verified after it has been submitted by a miner. Do they already have a previously calculated block hash DB or something else? I m new ...
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1answer
56 views

Bitcoin's cryptographic protocol allows for leakage of information about one's Private Key, making recalculation of the private key possible?

Is it true that the cryptography which is used in bitcoin allows for leakage of information which could be used to recalculate the private key - IF you are continuously reusing the same public address ...
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How are the prefixes for EXT_PUBLIC_KEY and EXT_PRIVATE_KEY derived?

I want to know how the prefixes for EXT_PUBLIC_KEY and EXT_PRIVATE_KEY are derived. For example in bitcoin you have: base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,0); ...
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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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What would a bitcoin quantum resistant address look like? [duplicate]

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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63 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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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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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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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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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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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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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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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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19 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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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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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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Is IQmining worth the investment? [closed]

I am interested in investing in crypto-contracts, is IQmining worth the investment?
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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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35 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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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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314 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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117 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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68 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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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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181 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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79 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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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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98 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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109 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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489 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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276 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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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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525 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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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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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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197 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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109 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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138 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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168 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 ...
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227 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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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 ...
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1k 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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Correct breakdown of the name of secp256k1?

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

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