Questions tagged [cryptography]

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

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1answer
111 views

Is 30,000 rounds really needed for PBKDF2?

In the browser, I'm using AES-256-CBC with 128bit IV & PBKDF2 to encrypt the mnemonic "tell file snow green proof evil six squeeze budget various orbit clock" with a password "s0mesuperl0ng!...
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1answer
13k views

Byte array to hexadecimal and back again in JavaScript [closed]

I can generate a byte array with var myByteArray = window.crypto.getRandomValues(new Uint8Array(16)) and I get 181,143,16,173,231,56,63,149,181,185,224,124,84,230,123,36 I can then turn this into ...
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158 views

Generating & Storing Private Keys

I'm now comfortable generating public and private keys for each user of a website. Is there any pro's / con's for generating the Private keys on the client in the browser or on the server? And once ...
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2answers
15k views

How to generate a Bitcoin Private Key Checksum

I want to understand how a bitcoin private key is made up. Looking at this graphical generator https://royalforkblog.github.io/2014/08/11/graphical-address-generator/#hello I understand step 1, how ...
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1answer
149 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 ...
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1answer
437 views

That hid Satoshi Nakamoto in your code [closed]

I tried to find in the code puzzles from Satoshi Nakamoto and I may have found them. How do you think the meaning of these symbols? https://github.com/bitcoin/bitcoin/blob/master/src/chainparams.cpp#...
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1answer
359 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 ...
3
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1answer
359 views

Understanding signing messages with bitcoinjs-lib

I'm trying to understand what a specific line of code does when signing a message using bitcoinjs-lib. Here's the code: var bitcoin = require('bitcoinjs-lib') var bitcoinMessage = require('bitcoinjs-...
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2answers
238 views

Why Bitcoin does not user bcrypt for hashing?

I've read that bcrypt is a hashing library that can adapt to Moore's Law and I thought that would be great for the network to adapt in a flexible manner its security to its respective growing ...
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2answers
949 views

Bitcoin Blockchain in the Quantum computing era

The design and the evolution of quantum computers has been one of the "hot" topics during the last 20 years. My question is about the possible consequences of the rise of quantum computers (through ...
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1answer
648 views

Why did Bitfinex choose to have access to all of its customers' private keys?

These wallets were “multi-signature,” which meant they came with more than one private key to access them. Bitfinex held two keys, while the multi-sig security provider, a company called BitGo, held a ...
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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 ...
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1answer
137 views

What cryptography hardware and/or software does a bitcoin exchange need to employ?

We have an operating equities exchange. To exchange bitcoin or other crypto-currencies, what cryptographic hardware or software would we have to use?
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1answer
295 views

Is BIP 32 Technology Cryptographic Curve Agnostic?

Does BIP 32 always implicitly assume secp256k1 elliptic curve cryptography (ECC) is to be applied, or can BIP 32 technology also be applied to create extended public or private keys that can readily ...
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2answers
873 views

Changing a private key of a public Bitcoin address

I would like a way to change the private key of a public address, for this you'd of course require the current private key. Is this at all possible? I want to prove that it can be done, or prove that ...
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2answers
515 views

Signing data with ECDSA

I was reading about the math behind bitcoins in this article, and one thing I can't seem to wrap my head around is how the said algorithm is used to sign "data". What exactly is this "data"? Is it my ...
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3answers
2k 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?...
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1answer
196 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" ...
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2answers
412 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?
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2answers
4k views

How to generate Ed25519 public key from private key using libsodium?

Not all crypto currencies are using secp256k1 technology for keypair generation and digital signatures. Curve25519 technology (frequently used to support ECDH key exchanges) is being used by a few ...
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1answer
185 views

Proving collisions on Bitcoin addresses without discovery of the private key?

If there is a private key that leads to a collision on an address, it is possible to show that the private key is not the one used previously, even though they have a collision on the address? ...
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0answers
205 views

Looking for a Project Ideas [closed]

Im a student at Sri Lanka institute of information technology and I am reading for cyber security BSc. I'm supposed to do a research project with a group of four people within an year. We are ...
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0answers
579 views

Cryptocurrencies based on RSA instead of ECDSA

Bitcoin is based on ECDSA. Does anyone know of cryptocurrencies based on RSA for authentication?
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1answer
303 views

Why is a chain code needed for entropy in HD wallets?

In the documents and articles I have read, it is stated that the "chain code" in HD wallets exists to provide entropy to the derivation of child public/private keys. If I understand the process ...
4
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1answer
159 views

Bitcoin's Cryptographic Integrity

A few people I know compare bitcoin and gold regarding currencies with integrity; Martin Armstrong on Zero Hedge compared both in a recent post. One advantage I currently see that bitcoin has over ...
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1answer
844 views

Using a Bitcoin or Litecoin miner for attacking PBKDF2 / SHA-256 [duplicate]

I'm wondering if it would be possible to utilize a Bitcoin or Litecoin miner to attack, say, a password database that uses PKBDF2 with HMAC / SHA-256. PBKDF2 uses multiple iterations of a PRF - ...
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1answer
175 views

What level of mathematical understanding do I need in order to contribute or to understand the crypto behind bitcoin?

My mathematical knowledge is up to CALC II (college level.) Is this enough mathematical maturity in order to understand the crypto in bitcoin or do I need more knowledge? If I do indeed need more ...
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1answer
107 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 ...
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2answers
11k views

ECDSA: (v, r, s), what is v?

Deterministically signing a Tx with RFC6979 returns v, r, s, where r and s are the 2 values used in standard ECDSA signatures. v = 27 + (y % 2), so 27 + the parity of r, as pybitcointools indicates. ...
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2answers
577 views

Is it possible to discover the set of bitcoin addresses from a public key?

I'm trying to find the set of bitcoin addresses from a public key associated with a user just to analyse this user transaction. Is there any way to derive/find all the addresses that have been ...
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1answer
541 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 ...
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1answer
169 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 ...
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1answer
93 views

Electrum 2 validation: how is the HMAC always 01…?

Electrum version 2 creates a seed from a random number which is then encoded as a mnemonic. The seed is validated by checking that the hmac begins with the bytes 01 or 101 for standard and 2fa types, ...
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1answer
797 views

HMAC “Bitcoin Seed” for BIP32

Pybitcointools uses the following code for calculating a master private key (BIP32) from a seed: def bip32_master_key(seed, vbytes=MAINNET_PRIVATE): I = hmac.new(from_string_to_bytes("Bitcoin ...
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0answers
566 views

Error While making windows.exe using gitian build?

Actually I'm making a logos windows exe (logosd and logos-qt) following the release process, which is mention on below path on any coin you can find that path, I'm working logos LGS Coin that's why I'...
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1answer
230 views

How do I create release build of my new bitcoin wallet?

I have created a new alt coin, and now I want to create a executable of my wallet in ubuntu. I don't know how to create a release build wallet with all its dependencies. How I can build my wallet ...
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0answers
75 views

Signing data with a namecoin private key? [on hold]

Consider the following scenario User A stores an image on a DHT and receives a SHA-256 hash in return. User A wants to prove ownership of the data has, so he registers a username on the namecoin ...
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1answer
2k views

Problems with deterministic ECDSA based on RFC6979 in Bitcoin

Generating random number k in elliptic curve is crucial and in any transactions signature in Bitcoin, random number k is required to compute a point k*G. If this k is chosen not randomly, it instantly ...
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2answers
1k views

How to generate a Litecoin Private key and correspondent Public Address in C#

I found this C# tool to generate addresses for Bitcoin (compressed and uncompressed): https://en.bitcoin.it/wiki/Bitcoin_Address_Utility https://github.com/casascius/Bitcoin-Address-Utility It ...
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0answers
105 views

Bitcoin-qt doesn't get a server connection?

I have created a new altcoin, and I run a server on one machine and connect bitcoin-qt on another machine. In this case it's blink the network connection, sometimes it shows one connection and after ...
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3answers
1k views

How do you derive the lambda and beta values for endomorphism on the secp256k1 curve?

You can see a little background about this on this bitcointalk post by the late Hal Finney. Beta and lambda are the values on the secp256k1 curve where: λ^3 (mod N) = 1 β^3 (mod P) = 1 As seen ...
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3answers
665 views

Papers/Books on how bitcoin works from a mathematical perspective?

I'm a math student interested in Cryptography. Is there any paper or book which explains, in mathematics and cryptography terms, how bitcoin (more general, a digital cryptocurrency system) works? In ...
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1answer
468 views

Is there a fallback plan if bitcoin's underlying cryptography is cracked?

Lets say someone started making real viable quantum computers that were affordable enough that large companies could buy one. And lets say a quantum algorithm was devised to crack the private keys of ...
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2answers
214 views

Hash property resistance

I'm experimenting with some self study cryptography and I was curious about the two following scenarios (simple answers and/or in relation to bitcoin) If SHA256 was found to lack pre-image resistance,...
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1answer
148 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. (...
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4answers
4k views

What exactly is generator G in Bitcoin's elliptical curve algorithm?

What exactly is the generator G in elliptical curve math? It is typically described as a point on the curve. Is this a tuple of values? What properties does it have?
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1answer
155 views

Anonymous transactions technology for a cryptocoin? [duplicate]

I’m thinking of investing in a cryptocoin with anonymous transactions feature. So far there are 3 well-known technologies for that: coinjoin (Bitcoin), masternodes (Darkcoin) and CryptoNote (Bytecoin)....
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2answers
146 views

Which cryptocurrencies deviate significantly from Bitcoin?

There's been dozens of alternate cryptocurrencies but I don't believe many of them did much other than find/replace some strings. We see Bitcoin as made up of the blockchain and proof-of-work via ...
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1answer
172 views

Bitcoin related research areas [closed]

I have a one year research project in my MSc curriculum. So i was suppose to address a existing issue in bitcoin protocol. Highly appreciate if someone can advise me and give me some ideas. Thank you....
3
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2answers
757 views

Are Bitcoin Block Hashes Predictable

to create the block chain, the Bitcoin network runs hashing algorithms for each block, is it mathematically possible to predict the hash value of say, the 100th block from the last block currently in ...