Questions tagged [cryptography]
Concerning the broad subject of cryptography and its narrow application in Bitcoin protocol and applications.
4
votes
1answer
25 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?
0
votes
1answer
18 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 ...
0
votes
1answer
50 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 ...
2
votes
2answers
216 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 ...
0
votes
1answer
28 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/...
0
votes
0answers
14 views
Does secp256k1 have any known weaknesses? [migrated]
I am wondering whether there are any properties of the curve which would technically make it easier to attack than any other curves of 256 bits in size.
I have heard that being a Koblitz curve, it ...
1
vote
1answer
62 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 ...
0
votes
2answers
56 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 ...
0
votes
1answer
33 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 ...
1
vote
1answer
89 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 ...
2
votes
1answer
90 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
votes
1answer
39 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 ...
-1
votes
2answers
111 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 ...
0
votes
1answer
93 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 ...
0
votes
0answers
22 views
Correct breakdown of the name of secp256k1?
sec Standards for Efficient Cryptography
256 256bit prime
k1 Koblitz curve no. 1
?
1
vote
1answer
139 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, ...
0
votes
0answers
15 views
Private Blockchains: Blocks’ validation
I’m a software developer and I’m trying to understand blockchain at a code level
I have the following issue:
There’s a private blockchain, this private blockchain does not have any relation to ...
7
votes
2answers
2k views
Is a bitcoin address collision possible if generating 90 million addresses every 4 hours?
I am running a test to see if I can obtain a successful bitcoin address collision after generating billions of addresses. I am not entirely sure how I would check them yet. Basically I have an extra ...
13
votes
1answer
2k views
What is the origin of insecure 64-bit nonces in signatures in the Bitcoin chain?
In Biased Nonce Sense: Lattice Attacks against Weak ECDSA Signatures in Cryptocurrencies Joachim Breitner and Nadia Heninger use a lattice based algorithm to recover private keys from signatures in ...
1
vote
1answer
46 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 ...
2
votes
1answer
195 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 ...
1
vote
1answer
47 views
Setup bitcoin-seeder
I wanna setup a dnsseed for a crypto currency using sipa/bitcoin-seeder on my VPS.
The server is hosted at NetCup and running the software as root, and also listening on port :53 UDP.
My domain is ...
0
votes
2answers
36 views
In theory could a pubkeyhash script be solved without the public key in the scriptSig?
When signing a pubkeyhash UTXO, it is required to provide both a signature and a public key. The public key is duplicated and one copy is provided to op_checksigverify to ensure the signature is valid,...
0
votes
2answers
38 views
How bitcoin gets monetary value [duplicate]
This looks like a complex thing but I am trying hard to understand it. Why would any one in the world honor a crypto currency till it is backed by a government with monetary value? How does a crypto ...
0
votes
1answer
377 views
Looking for code generate bitcoin address from passphase in C++
i'm try to write a program which generate bitcoin address from given hash sha256 of passphase as private key or given hex private key. I've found a library for this but it required Boost package in ...
0
votes
1answer
37 views
Is hashing an optional step to use with public key cryptography for blockchain
I am confused by the public key cryptography versions that I've read so far. Are the steps optional, dependable on the types of blockchain or they are referring to different methods?
Version 1 =======...
0
votes
2answers
44 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 ...
0
votes
2answers
92 views
How to get the generator G point for any new curve?
I have this bitcoin curve:
y^2 = x^3 + 7
but the finite field Fp is modified to be:
n=115792089237316195423570985008687907853269984665640564039457584007908834675927
1-What is the G point?
2-how ...
-1
votes
1answer
57 views
proof of stake concept and implementation confusion
i'm currently studying proof of stake concept in cryptocurrency in preparation of building it soon, but i still have some doubts about my understanding of the concept itself, and i have a lot of ...
1
vote
0answers
129 views
Idioms of use/ bitcoin heuristic
I already know the answer of a) part which is Alice. Can anybody help me in finding answer of b) part.
2
votes
1answer
25 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.
0
votes
1answer
56 views
Can Bitcoin Tech be Used to Protect Journalists [closed]
Over eight Nigerian journalists are currently in police detention because they published investigative news stories that didn't sit well with the government of the day.
How can the bitcoin ...
0
votes
1answer
30 views
Have all hashes of unlocked difficulty levels of cryptocurrencies been mined?
I'm wondering if all the hashes of a previously unlocked difficulty level of a cryptocurrency, such as
0000000000000000xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx BTC
, have been completely ...
0
votes
1answer
37 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 ...
1
vote
1answer
101 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
...
1
vote
2answers
54 views
Is there a single point generator G for every elliptic curve?
I understand that G is a point on curve which holds true for y^2 = x^3 + ax + b.
But there can be several other points as well which holds true for above equation but how do we choose which one is our ...
1
vote
0answers
39 views
Could a network described below function and how well?
I have an idea I am working on for some time, it would be using blockchain technology. However, although I know something about blockchain as it stands today, I am lacking a more deepened knowledge ...
0
votes
1answer
189 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 ...
0
votes
0answers
116 views
Would it be possible for an 8-bit microprocessor to create a bitcoin keypair?
Context for question: With the latest security breaches around modern CPU's (Spectre / Meltdown) I was wondering if we could generate ECDSA keypairs on cheap, small and/or simple air gapped (micro)...
1
vote
3answers
407 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 ...
0
votes
2answers
135 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....
3
votes
1answer
688 views
SECP256K1 Minimum Value for Private Key
I've been looking into Elliptic Curve Cryptography, in particular the SECP256K1 spec which is used in Bitcoin and Ethereum. So I understand that the Generator point G is fixed based on the spec and ...
0
votes
3answers
712 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?
5
votes
2answers
433 views
BIP32 recommends a 256 bit seed. Why do most Bitcoin wallets only use a 128 bit seed?
According to BIP32's "Master key generation" section, "256 bits is advised".
See https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki#Master_key_generation
Why did BIP32 consider 256 bits ...
0
votes
1answer
1k views
Cryptocurrency Exchange Technical architecture? How to build it? (Developer Point of View) [closed]
I'm a softawre developer & newly involved in Blockchain Technology.
I need information about How Cryptocurrency Exchange Technically work?
i.e Buy ETH using BTC or exchanging any coin with ...
1
vote
0answers
268 views
Ed25519 Successor to ECDSA in Bitcoin?
Bitcoin is currently using the secp256k1 curve. Understand that Ed25519 is technically superior -- i.e., offers better security than ECDSA and DSA, speed and most importantly, I think, resistance ...
0
votes
1answer
347 views
How can I create uncompressed public key in C++?
I need to derive public key from my private key in uncompressed form. I know how to create compressed one with libbitcoin, but I can't find appropriate method for uncompressed form there.
Are there ...
5
votes
1answer
142 views
what is a discrete logarithmic assumption? how does it set-up trustless proofs?
pending proposal of bulletproofs as a zk proof for confidential transactions relies on fiat-shamir heuristic to be non-interactive via creating a digital signature on interactive proof of knowledge ...
0
votes
1answer
381 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 ...
2
votes
1answer
59 views
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 ...
