Questions tagged [cryptography]

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

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86 views

Cryptographic problem - locks [closed]

Three players, Bob, Alice and Ted are seated at a poker-table and are  playing a game of Texas Hold’em. Bob is the dealer, and he generates a deck of 52 cards on his machine, only he can view the ...
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1answer
23 views

Is it possible to use something besides sheer computational power as the limiting factor on block release?

Why hasn’t anyone tried to create a blockchain that, rather than using computational capacity as the hash scarcity test, just has a direct limit on how many times a particular wallet can make a guess ...
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1answer
258 views

Mycelium Backup Restore

Is there a way I can restore my mycelium Bitcoin wallet if I have forgotten the 12-word list? I have searched everywhere and no one describes a situation like this.
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2answers
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 (...
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2answers
2k views

Do all Cryptocurrencies uses same Public key Cryptography algorithm?

I have been trying to read about how Public key cryptography works and I have just understand what public key cryptography is and how it differs from symmetric key cryptography. I have also just read ...
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1answer
494 views

Is there a point on the secp256k1 curve for any given X coordinate?

There function in libsecp256k1 that allows you to directly set the field element to 32 bytes of your choice. Does secp256k1 always return a valid group element for any 32 byte value? ...
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0answers
222 views

Bitfinex API -> retrieve funding earnings for custom period

I am trying to retrieve my funding profit of the previous day via the Bitfinex API. But all I find is this API which only returns the profit of the last 30 days summed up (funding_profit_30d): https:...
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1answer
44 views

Is it possible for a currency to give coins pub/prvt keys instead?

So the idea is you would have coins and non-coins. A coin is something you could be in possession of but can only prove it by signing messages. If you wanted to transfer it to somebody you would send ...
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0answers
28 views

How the buy/sell rate of bitcoin is continuosly increasing? [duplicate]

I am continuously monitoring bitcoin rate since last one month using an android app (zebpay). The buy/sell rate reached double fold within one month. I never seen it decreasing. Considering me a ...
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1answer
793 views

How to create a deterministic wallet using bitcoinjs-lib

I'm new to bitcoin technology, however, I'm trying to develop a web wallet using bitcoinjs-lib that works like that of blockchain.info. I've gone through the code samples on the github repo but couldn'...
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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
14k 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
16k 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
151 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
440 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
361 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
383 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
256 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
954 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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0answers
38 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 ...
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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?
3
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1answer
305 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
921 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
529 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
200 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
416 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
189 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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586 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
313 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
160 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
865 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
179 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
12k 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
607 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
550 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
95 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
825 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
571 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
234 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
77 views

Signing data with a namecoin private key? [closed]

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 ...