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Questions tagged [cryptography]

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

4
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1answer
29 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
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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
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1answer
52 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
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2answers
221 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
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1answer
29 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/...
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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
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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 ...
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2answers
58 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
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1answer
34 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
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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
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1answer
91 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
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1answer
40 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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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
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1answer
96 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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0answers
22 views

Correct breakdown of the name of secp256k1?

sec Standards for Efficient Cryptography 256 256bit prime k1 Koblitz curve no. 1 ?
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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
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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
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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 ...
14
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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
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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
199 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
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1answer
49 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 ...
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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,...
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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
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1answer
386 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
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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 =======...
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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
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2answers
93 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 ...
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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 ...
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0answers
130 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
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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
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1answer
57 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
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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
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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
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1answer
102 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 ...
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2answers
55 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 ...
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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
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1answer
192 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
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0answers
119 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)...
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3answers
411 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
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2answers
136 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
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1answer
700 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
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3answers
730 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
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2answers
438 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
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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 ...
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0answers
271 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
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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
143 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
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1answer
384 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 ...