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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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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
2 votes
1 answer
208 views

Using key aggregation (multsig) in P2TR script path spends

I know that it is possible to create a 2-2 multsig using Taproot by combining both private keys into one public key and defining that as the key path spend. I also know that it is possible to use ...
Hellwerker's user avatar
2 votes
2 answers
178 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? ...
Satoshi's user avatar
  • 21
2 votes
1 answer
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Needed maths for full understanding

I often come across papers written in the Bitcoin space involving some math that I am not formally versed in. Could anyone point out general topics in math that I should have a formal grasp on in ...
jojeyh's user avatar
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3 answers
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Would writing one's own cryptocurrency in a language other than C/C++ be stupid?

I'm curious from a performance perspective if writing a cryptocurrency from the ground up in a language other than C/C++ be stupid? For example, if I wanted to write a cryptocurrency and protocol in ...
Ben B's user avatar
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3 answers
6k views

How proof of work prevents double spend

One article I am reading said that proof of work system is used in Bitcoin to prevent double spending. More particularly: Imagine we are protecting against double spending in following way. When Bob ...
user avatar
2 votes
1 answer
396 views

How does ring signature help in range proofs in confidential transaction?

Based on Maxwell's proposal of confidential transaction, a ring signature can solve the range proof issue. I can totally follow the pedersen commitment and everything. I don't quite get how ring ...
abeikverdi's user avatar
2 votes
1 answer
852 views

Ramifications of creating Electrum 2.x seeds which are not BIP39

Electrum 2.0 seeds (mnemonic phrases) are created with a checksum based algorithm (such that the hmac_sha512 starts with 01. It's usually a 13 word seed, but can be 12 in some circumstances. If all ...
Wizard Of Ozzie's user avatar
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1 answer
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Should I use a large random value for i in BIP 32 instead of sequential?

BIP32 doesn't have any guidance on how to choose the i value for child keys. Is there any benefit to using a random value for i ? Other than documenting and saving the value of I for various ...
makerofthings7's user avatar
2 votes
3 answers
2k views

Why is Bitcoin better than other cryptocurrency? [duplicate]

If there too many types of such kind of currency, will them be very cheap? I have 4 BTC and since the current BTC price waves a lot, I am wondering this. Thanks,
AGamePlayer's user avatar
2 votes
1 answer
979 views

What is the Elliptic Curve algorithm used in Ripple to generate public / private key pairs?

The algorithm used by bitcoin to generate keys is secp256k1, is it the same for ripple?
Steven Zeiler's user avatar
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1 answer
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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
2 votes
1 answer
363 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
2 votes
1 answer
159 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 ...
Matt's user avatar
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1 answer
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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 ...
bitlobo's user avatar
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2 answers
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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.
nutred's user avatar
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2 answers
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cryptography book or resource

I am trying to write a multiple currency hd wallet. I am using javascript libraries but I feel unsafe as I am new to most cryptography concepts and terms like elliptic curve, seeds, entropy etc. I ...
Cem Karay's user avatar
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1 answer
193 views

Given a set of consecutive HD private keys, can you generate the next private key without knowing the master private key?

I'm wondering whether disclosing a consecutive number of HD private keys derived from a given master key would allow someone to compute what the next private key in the sequence would be before it is ...
ThePiachu's user avatar
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2 votes
2 answers
845 views

Is Bitcoin mining chance based?

This answer says that Bitcoin is not chance based, may I know how it is deterministic and does not have any associated probability of mining a coin?
Ali's user avatar
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1 answer
168 views

What is the algorithm used to sign data within Nxt?

I understand that Nxt uses Curve25519 to generate pubkeys for user accounts, however, I can't find a reference that states what which signing algorithm/process is used for transactions and blocks. (...
RLH's user avatar
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1 answer
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ECIES - When is it bad to sign and encrypt using the same keys?

Suppose I have a public key for a particular user (perhaps extracted when using the new public key recovery format included in P2SH, and BIP32 transactions). Is it OK the same key for both signing ...
makerofthings7's user avatar
2 votes
2 answers
349 views

When will the public key of an address used in the network?

On block explorer there are some address with public key available, and some without. (e.g. this one has public key: http://blockexplorer.com/address/1HBheYzvX7NDtcwVrMS7gxReNRVezYS7w2 , and this ...
h__'s user avatar
  • 433
2 votes
1 answer
5k views

How does bitcoin work from a technical computer science cryptography perspective?

How does the cryptography science behind bitcoins work to make it robust(reliable , scalable). I am interested in technical explanation with cryptography math and not just conceptual explanation.
Ali's user avatar
  • 265
2 votes
1 answer
404 views

How can I use message signing to prove that I have private keys for many different accounts?

I want to prove the total sum of BTC I have access to. Therefore I think if I use message signing to assert "owned by makerofthings7" in each address, then anyone can compute the total coins in my ...
makerofthings7's user avatar
2 votes
0 answers
121 views

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 ...
Jayyy777's user avatar
  • 141
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1 answer
103 views

How would Bitcoin’s cryptography change?

Let’s say, that 20 years ahead, Bitcoin’s crypto is not considered secure anymore. More precisely, the key length is too short for it to be safe, be it the hash functions or public key cryptography. ...
Fischa7's user avatar
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2 votes
0 answers
42 views

How does lighting network ensure all parties cooperate [duplicate]

I somewhat understand the two way channels used in lightning. But I fail to see how trust is avoided. If I'm the middle node I'm perfectly fine with forwarding a payment, if I received the payment ...
jvanbec's user avatar
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2 votes
0 answers
83 views

Does Amit Sahai's indistinguishability obfuscator enable Autonomous Virtual Corporations or "Agents"?

Given that an "Agent" is described as Agents are autonomous programs that maintain their own wallet, which they use to buy server time. Money is obtained by the agent selling services. If demand ...
makerofthings7's user avatar
1 vote
2 answers
1k views

Private key and Address

Private key is 32-byte number. Address (Hash) is 20-byte number. Is it true that there is many Private keys that have the same 20-byte hash? P.S. How to get Address from Private key: Private key (...
Denis Leonov's user avatar
1 vote
1 answer
453 views

Why are blocks hashed?

Am I correct that addresses are hashed to compress a huge text-represented coprime into something of manageable size? Am I also correct that transactions are hashed for the same reason and also ...
user avatar
1 vote
2 answers
378 views

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 = ...
Izi Tors's user avatar
1 vote
1 answer
292 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 ...
kcalvinalvin's user avatar
1 vote
1 answer
2k views

What is the difference between digital signature and a digital fingerprint?

I've been reading the book, Mastering Bitcoin by Andreas M. Antonopoulos, in chapter 4, the cryptography used in bitcoin is classified as: keys, bitcoin addresses and digital signatures. I understand ...
Ang's user avatar
  • 17
1 vote
3 answers
5k views

Get uncompressed public key from compressed form

A similar question has an answer in Python which links to the bitcointalk forum: How can I get the uncompressed public key from the compressed public key in openssl? https://bitcointalk.org/index.php?...
prof.Zoom's user avatar
1 vote
1 answer
255 views

Some technical questions about Bitcoin [closed]

I'm a developer. I've read a lot about Bitcoin structure and how it works. But yet something confuse me. I would like to share them with you and read your answers: When a miner solves a block, how ...
james hofer's user avatar
1 vote
1 answer
194 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 ...
Ugam Kamat's user avatar
  • 7,417
1 vote
1 answer
545 views

How specific are ASIC's design? Can they single hash SHA256?

I understand that Bitcoin's ASICs are a highly optimized piece of equipment and, therefore, are also very specific. My question: are they able to do a single (or triple?) SHA-256 hash at all? And, ...
Tiago Loriato Simões's user avatar
1 vote
1 answer
84 views

Security implications of removing CHECKSIG in a test

If I conduct an htlc transaction on testnet that does not include OP_CHECKSIG will it still cost an attacker more than (say) $10 in processing power or storage to subvert my tests? Details: I'm ...
Alistair Mann's user avatar
1 vote
3 answers
935 views

Public key cryptography question - Is Private or Public key used to sign? Confusion between which key is used to sign and which is used to encrypt

I am relatively new to cryptography and blockchain and am learning about how public key cryptography works, and its application in Bitcoin's environment. I read two different articles , the 1st which ...
DCH's user avatar
  • 77
1 vote
2 answers
173 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
1 vote
1 answer
164 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 vote
1 answer
128 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 ...
Marieanndrasuper's user avatar
1 vote
2 answers
124 views

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”?
Martin's user avatar
  • 11
1 vote
1 answer
78 views

Multisig Wallet Question

I think I understand multisig wallets: X out of Y signatures are required for a transaction to be made. My question is: is there such a thing as a multisig wallet where any ONE of the allowed ...
aroooo's user avatar
  • 165
1 vote
1 answer
170 views

How to prove bitcoin ownership without revealing amount?

Is it possible to use some cryptographic scheme to prove bitcoin ownership without revealing any information about value held in addresses?
rny's user avatar
  • 2,428
1 vote
1 answer
427 views

How can anonymity and uniqueness be achieved in the blockchain?

How We Use Elliptic Curve Cryptography At Follow My Vote, we use this technology to create votes. During the registration process, voters create two ECC key-pairs. The voter reveals her identity to a ...
Lay González's user avatar
1 vote
1 answer
261 views

Are Hashed Timelock Contracts and Zero-Knowledge Contingent Payments the same thing?

This answer to How is a node in the middle prohibited from keeping the money in a routed Payment in Lightning network? describes how a Hashed Timelock Contract would be used to exchange the "secret" ...
Murch's user avatar
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1 vote
1 answer
150 views

Getting bitcoin globe data

I just saw this bitcoin globe https://blockchain.info/nodes-globe?series=topBlockRelay It has two modes,"Online Now" and "Miners". I wanted to ask if anyone knows what the bars and colors stand for ...
m0j1's user avatar
  • 113
1 vote
1 answer
197 views

Authentication and key distribution in bitcoin

After going through the bitcoin protocol documentation it is still unclear to me how the bitcoin client is authenticated. Where can I find an overview of what the client sends and receives on the wire ...
Sebi's user avatar
  • 151
1 vote
2 answers
576 views

Multibit: Using the same passphrase for both my wallet and exported private keys

I have a password-protected wallet in Multibit that I have backed up in multiple locations. I have exported the private keys from this wallet. The private keys are password-protected using the same ...
Blaise's user avatar
  • 113