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Questions tagged [cryptography]

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

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Is it possible to reduce the field size without disrupting generation of public keys?

I have a curious question, i am aware of the curve parameters of secp256k1. i was wondering if its possible to reduce to field to a 130 bit or lower without disrupting the actual functionality.. what ...
Melwyn's user avatar
  • 9
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0 answers
37 views

Bitcoin Core VM and hardware SHA256

It has come to my attention recently that linux machines store info about their cryptographic capabilities in /proc/crypto. A baremetal machine I have shows sha256_ssse3 in the sha256 module parameter,...
RooSoft's user avatar
  • 157
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0 answers
22 views

How to know the number of digits in the decimals place in division results (ECC SECP256K1)?

p - is the order of the finite field n - is the order of the group. Private keys can range from 1 (the generator point G) to n - 1. All the private keys (Priv) lie in certain ranges of 2. 2^a < ...
Maltoon Yezi's user avatar
4 votes
1 answer
378 views

Why does BIP-340 use secp256k1?

If the entire Taproot/Schnorr soft-fork was going to implement an entirely new signing scheme anyway that was completely independent from the previous ECDSA scheme, why did it use secp256k1? Couldn't ...
fiatjaf's user avatar
  • 611
1 vote
1 answer
36 views

What is one word seed word exactly?

I have the following code import hashlib import binascii def word_to_private_key(word): sha256_hash = hashlib.sha256(word.encode()).digest() private_key = binascii.hexlify(sha256_hash).decode(...
Asif Iqbal's user avatar
0 votes
0 answers
80 views

Is it safe to share half of the private key in WIF format?

Assuming I would generate my keys on https://www.bitaddress.org. Is it safe to share the following four pieces of data? One half of the private key. The public key. An SHA512 hash of the private key. ...
Ohumeronen's user avatar
2 votes
1 answer
175 views

Why is the challenge scalar multiplied with the private key scalar In the Schnorr identification protocol?

If Alice wants to prove to Bob she is the holder of private key x, without exposing x, they can use the Schnorr identification protocol which has the public function sG = kG + exG and the private ...
yonson's user avatar
  • 43
1 vote
0 answers
85 views

Decrypting wallet

I'm seeking assistance with understanding the technical aspects of how Electrum wallets handle parsing errors and potential solutions for resolving them. My friend has encountered a recurring issue ...
Dirk's user avatar
  • 11
0 votes
1 answer
94 views

Public key factors - but what's next?

Let's say I found (I know, impossible) public key factors. What to do with them next to compute original private key for that public key?
pbies's user avatar
  • 159
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0 answers
56 views

Unconfirmed bitcoins deposit from online casion. they paid a fee of 1.82 on a 4k withdrawal.. what do I do? [duplicate]

I made a bitcoin withdrawal from a online casino of $4000. They sent me the payment but it won't confirm. I see they payed a fee of $1.82 so I'm sure thats why it hasnt confirmed yet but Its been a ...
That one dude's user avatar
2 votes
1 answer
189 views

Probability of Generating a Bitcoin Address with Specific Starting and Ending Characters

I've recently come across a situation where scammers are generating (bitcoin) addresses that have the same starting and ending characters. This is concerning as many people, including myself, often ...
Oliver Offing's user avatar
8 votes
1 answer
151 views

Why doesn't Bitcoin Core use auxiliary randomness when performing Schnorr signatures?

BIP340 recommends using auxiliary randomness in generation of the Schnorr signature nonce, as follows: Using unpredictable randomness additionally increases protection against other side-channel ...
Matthew Leon's user avatar
11 votes
3 answers
4k views

How can I manually (on paper) calculate a Bitcoin public key from a private key?

I am interested in generating a Bitcoin address by hand for security's sake. After I choose/generate a private key, how do I generate the public key? From there, how would I double check my work? ...
Peter Bergman's user avatar
0 votes
0 answers
120 views

Derive Secp256k1 curve public key starting off from known 32 bytes string

Starting off from a sha256 hash of a threshold pubkey, how can I generate a valid secp256k1 public key? The challenge is that the 32 bytes of the hash does not always fall within secp256k1 range, so I ...
okjodom's user avatar
-2 votes
1 answer
95 views

What is the step-by-step algorithmic process to find the modular multiplicative inverse of (n-1) mod np, where (n-1) and np are not coprime?

Having perused the stackexchange, I found some similar questions, but am having difficulty understanding how to arrive at the solution to (n-1)*x=1 mod np, where: n: Finite group order of the Bitcoin ...
Alfhilðr ínn Seiðkona's user avatar
0 votes
0 answers
54 views

Bulletproofs vs Merkle paths for inclusion proofs

In this blog post, Andrew Poelstra comments that bulletproofs can be used for efficient merkle inclusion proofs. How would these proofs compare in size and verifying time to simple merkle paths? Take ...
Son Kaos999's user avatar
1 vote
2 answers
170 views

What does it mean for an integer to be a member of secp256k1 group?

I'm reading the spending section of BIP47: Alice calculates a scalar shared secret using the x value of S: s = SHA256(Sx). If the value of s is not in the secp256k1 group, Alice MUST increment the ...
Merri's user avatar
  • 13
12 votes
1 answer
408 views

How does this field multiplication in libsecp256k1 work?

I'm looking at libsecp256k1's codebase, for learning reasons (doubt I can contribute with anything useful there). While looking at the field implementation, the implementation of ...
Davidson Souza's user avatar
2 votes
1 answer
196 views

weak transaction in secp256k1

My question is related to weak signature vulnerability testing where a hypothetical attacker does not know the values of the nonce or private key itself, but can determine that the nonce 'k1' is ...
Ironic's user avatar
  • 23
0 votes
1 answer
58 views

Why does the Bitcoin network encrypt the transaction data? [duplicate]

The whole process of encryption sounds useless to me. Miners/validators and full nodes need to verify each transaction. They need two pieces of information: The original transaction data The ...
Curious George 's user avatar
2 votes
1 answer
88 views

Where is chacha20 and chacha_poly_aead used in Bitcoin Core?

In the source code of Bitcoin Core there are these functions but no explanation of how and where they are used. I need to make a description for all crypto-functions used in Bitcoin Core (https://...
Gregory Morychev's user avatar
0 votes
1 answer
112 views

How to encrypt messages with Pub/Priv keys

I'm wondering if it's possible to use the Bitcoin public and private keys (usually used for signing) for text encryption. This is an example in nodeJs: import pkg from 'bitcore-lib' const { ...
Cartucho's user avatar
  • 123
4 votes
1 answer
185 views

How does the BIP340 lift_x algorithm work?

Couple questions of code that I'm reviewing trying to learn schnorr sigs. Why do we want an odd private key? I see even tests on the private key and then subtract it from the SECP256K1 Order to get an ...
Kaizen's user avatar
  • 331
2 votes
1 answer
371 views

Why bitcoin's generator point does not satisfy Elliptic Curve Cryptography equation?

This is my Python program: Acurve = 0 Bcurve = 7 Gx = 0x79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798 Gy = 0x483ADA7726A3C4655DA4FBFC0E1108A8FD17B448A68554199C47D08FFB10D4B8 print(...
Devanshu Linux's user avatar
0 votes
0 answers
86 views

Is www.soloxbit.com a legitimate exchange? [duplicate]

help is needed urgently. I have been invited to use a crypto exchange called www.soloxbit.com by a telegram group. I signed up as there was a 50% bonus on my first deposit using their referral. My ...
Brian Lim's user avatar
2 votes
1 answer
335 views

Why g is 2 and 3 to derive the lambda and beta values for endomorphism on the secp256k1 curve?

As you can seen here, in hex, N and P are: N = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE BAAEDCE6 AF48A03B BFD25E8C D0364141 P = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE FFFFFC2F The ...
tony pham's user avatar
0 votes
1 answer
310 views

What's the difference between the anti klepto protocol and anti exfil?

What is the difference between the anti-klepto protocol (also here) and Anti-Exfil? Is it the same thing just with different names or are there differences? It seems they are both addressing the nonce ...
Michael Folkson's user avatar
0 votes
0 answers
83 views

problem accessing wallet

I have a 2011 wallet.dat created in version 0.4.0 it accepts my password normally. but when putting in the current version of bitcoin core it doesn't work can you help me? If I enter any other (not ...
Magno Lobo's user avatar
2 votes
2 answers
691 views

Why can't I reverse secp256k1's public key point in order to determine the private key?

I understand that the public key q is generated by the point addition of g (some secp256 k1 constant) u times such that u is a big number (private key). This process can be simplified in this diagram ...
Jamo's user avatar
  • 167
-2 votes
1 answer
51 views

What is the best way to check multiple crypto coins payments are paid - NODE JS

I am trying to write a gateway system where users can check the data upon the callback that is sent to their specific url. I am wondering how I could go about checking that the payment has been ...
php dev's user avatar
0 votes
1 answer
212 views

How do we know that Bitcoin supply is actually capped at 21 million?

Everyone says that the Bitcoin supply is capped at 21 million. But how did everybody come to this number? In Nakamoto's paper, I could not find this number. Can someone explain where it is or how we ...
TFT's user avatar
  • 103
2 votes
1 answer
344 views

How to calculate the public key, compute point P and create signature using ECDSA?

I'm quite new to the intricacies of bitcoin cryptography and ECDSA and elliptic curve cryptography has me quite stymied. I am faced with a curve with the equation: y^2 = x^3 + 7 of order N=39 with ...
Raighley's user avatar
12 votes
2 answers
3k views

How is the generator point G chosen in the secp256k1 curve used in Bitcoin?

The generator point G in the secp256k1 curve used in Bitcoin is a known constant: Gx = 0x79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798 Gy = ...
RocketNuts's user avatar
  • 1,061
0 votes
1 answer
39 views

Is it Possible to Create Signature Chains for Private Keys to Sign Transactions with? Similar to how Certificate Authorities Use Intermediate Certs?

I am wondering if it is possible to implement this flow with bitcoin private keys, similar to how certificate authorities have a root cert and an intermediate cert used to sign csr's. It would be ...
bobandweave's user avatar
0 votes
1 answer
114 views

Is it possible to compute just a byte of the public key by having the private key?

Let's say we have a certain known public key to which we want to find the private key with a bad approach such as brute forcing. Would it be possible that instead of computing the whole public key to ...
JKS's user avatar
  • 3
1 vote
0 answers
107 views

What needs to be changed in Bitcoin if SHA-256 is broken? [duplicate]

I come up with a little bit "catastrophical“ question. I declare that I understand the degree of improbability of such a scenario in our lifetime, but I would still be interested in your opinion. ...
Adam's user avatar
  • 11
0 votes
1 answer
582 views

What happens to the public and private keys after a transaction? Specifically, how (and why) do they change upon payment?

Feel free to answer/address as many of these topics as you like: In particular, I am interested in how bitcoins can be stolen, e.g., the 2016 Bitfinex hack. If I am not mistaken, the only way to steal ...
Kevin's user avatar
  • 3
1 vote
1 answer
135 views

How transactions script work?

I am trying to learn Bitcoin in some technical details, but I don't really understand the process of locking and unlocking scripts. I know that for what they are using, but can someone explain me some ...
Dev Per's user avatar
  • 11
0 votes
1 answer
136 views

How do nodes fetch unconfirmed transactions?

I'm taking up a project to build a software in python to mine cryptocurrency (preferably bitcoin). I have an overview of the computation that needs to be done. I would like to know how nodes fetch ...
Sarath Jyothis's user avatar
1 vote
1 answer
161 views

BIP 32 CKDpriv not working in my python implementation

I have been working on implementing BIP 32 in Python. This is my code for deriving normal (not hardened) child keys as part of an HD_Key class: def CKDpriv(self, index): key = bytes.fromhex(self.c)...
ana408's user avatar
  • 47
-1 votes
1 answer
56 views

how does new exchanges order books work?

When a new exchange is launched and it doesn't have many users, how does it managed an order book? how can they match orders when there's not enough of them?
pardis.ti's user avatar
-11 votes
1 answer
1k views

Can I be rewarded for discovering, creating, and proving bugs on Bitcoin?

There has never been a remittance history to this address. https://www.blockchain.com/btc/address/1JqPFnGPhHhy54zJKmC1MPiczzgFjCmzE9 public key : ...
user121477's user avatar
0 votes
1 answer
94 views

BT wifi Internet router not detecting S9K miner

I am mining crypto via GPU & ASIC miners. I recently bought an S9K Antminer which powers on perfectly fine; however as we all know, it needs to connect to the internet via an ethernet cable. This ...
user130832's user avatar
0 votes
1 answer
502 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
1 answer
88 views

If you lose your Bitcoin wallet Password, can you simply transfer private key to another bitcoin wallet provider?

If you lose your Bitcoin wallet password, can you simply transfer private key to another bitcoin wallet provider? I mean if I lost the password to the website where the wallet is stored, can I simply ...
Chris J's user avatar
  • 113
0 votes
3 answers
192 views

bitcoin private key usage

My next question is how Private Key needed to spend coins. According to my understanding for transaction needed below steps: A wants to send 10 coin to B A make transaction example: from: A, to :B ...
aze2201's user avatar
  • 101
0 votes
1 answer
43 views

how target walled address is secure to save received amount?

What about if I (as a hacker) change the amount from 5 to 1 for any transaction and put signature with my (as a hacker) Private Key and mine that block again. Yes, I lose 1 coin, At the same time isn'...
aze2201's user avatar
  • 101
0 votes
3 answers
86 views

Long-term present in a form of cryptocurrency for newborn

Lets go... I am relatively new to to world of crypto. Have some experience with Binance, last few weeks. My friend had a son, and I want to give him a little different present - crypto investment in a ...
intni's user avatar
  • 1
0 votes
2 answers
281 views

Can we have multiple possible nonce making same number of leading zeroes in the hash?

Is it possible to have different nonce which are satisfying the same condition of having let's say 4 leading zeroes in the hash? Is it possible that one node suggests 89123 nonce and other node ...
Mathew Pitcher's user avatar
3 votes
1 answer
179 views

Why does the chacha20 implemented in the Bitcoin Core use a 64 bit nonce?

The draft of chacha20 uses a 64-bit nonce, but the final version of chacha20 specification uses a 96-bit nonce. The #9792 PR adds chacha20 to Bitcoin Core. We can see the function ChaCha20::SetIV(...
siv2r's user avatar
  • 33

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