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30

There's a lot of confusion here, mostly bits and pieces of the whole scheme that is Hierarchical Deterministic derivation, and finally two questions that seem to indicate missing some point about it. The answer to the first question is No. The second question is more interesting : Let's start from extended keys, specifically BIP32 keys. Like private keys ...


29

I couldn't find the results of the Coin Selection written out anywhere, and just finished piecing it together from the code. It works as David mentioned, but here are more details. The Coin Selection Algorithm logic to transfer Target amount If any of your UTXO² matches the Target¹ it will be used. If the "sum of all your UTXO smaller than the Target" ...


29

First you must configure your bitcoin.conf file for JSON-RPC rpcallowip=127.0.0.1 rpcuser=yourusername rpcpassword=reallystrongpasswordthatsnothis rpcport=7788 walletnotify=/home/scripts/transaction.sh %s Where transaction.sh is some bash program. One approach is to have it make an http request to some process to notify you of the deposit. An example: #!/...


29

The address received 0.07014343 BTC in 3d727e3f4565e011c0348f813c2d5480210b6bae2003a0f7abaa949d1a7c599a. These coins have already been spent, so at the very least the recipient's wallet provider is aware of the transaction. Depending on the type of wallet, the recipient's account may not have been credited due to internal system issues. Alternatively, the ...


28

There is no such thing as a transaction "balance". I am going to assume if I jump right to the answer it won't make much sense so the first two sections are to make sure we are how Bitcoin "really works" (at a very high level abstracted view). We need to speak the same language for the answer to make any sense. For this question the two required concepts ...


27

If you don't want to read the whole list, and just want to choose a Bitcoin Cash wallet... (SPV = Simplified Payment Verification, does not depend on a server so it's a more decentralized.) Sorted by various things For PC/MAC Electron Cash (a.k.a Electrum for Bitcoin Cash) For Android CoPay (SPV) BTC.com UnitWallet (SPV) For iOS CoPay (SPV) Bitcoin....


24

from: https://github.com/schildbach/bitcoin-wallet/tree/master/wallet The backup file is encrypted using your chosen password. You can use OpenSSL to decrypt: openssl enc -d -aes-256-cbc -a -in <filename>


23

Thomas' answer is correct, but I think an easy version may be appreciated as well. I suppose you know the concept of public key cryptography? If you don't, here is a very short explanation (or read the wikipedia page): Public key cryptography (as used in Bitcoin), allows you to hand people a public key and use the corresponding private key to prove the ...


23

To actually try and answer your question, Mt Gox acted as a trusted middleman in btc trading, and thus had to have control over their users money. Let's say dude A has a few btc he wants to sell, and dude B has a few dollars he wants to buy btc for. B doesn't want to pay until A sends him the btc, and A doesn't want to send his btc to B until B pays. ...


22

This is mainly adding to @Raghav Sood's answer: A quick google search brought me here from which I found this: https://blockexplorer.com/ Searching your bitcoin address in this website gives some data related to bitcoin transaction concerning this particular address (including the one mentioned on the other answer), plus some more statistics. For ...


19

Yes, you could send bitcoins directly to the public key: in fact, both Pay-to-PubKey (P2PK) and Pay-to-PubKey-Hash (P2PKH) were introduced in the first Bitcoin release. IIRC, P2PK is still used for Coinbase transactions sometimes, today. P2PK transactions are slightly bigger for outputs but significantly smaller for inputs. One advantage of P2PKH is that ...


18

With HD wallets, a single key can be used to generate an entire tree of key pairs. This single key serves as the "root" of the tree. The word seed is simply a more human-readable way of expressing the key used as the root, as it can be algorithmically converted into the root private key. Those words, in that order, will always generate the exact same key. ...


18

I like to suggest a mental model where the network is a metals forge: You have a 1 oz gold coin stamped with your key on it, with your transaction you send it to the forge to be melted down and re-formed to two new coins, a .22 with Alice's key stamped on it and a .77 with a key of yours on it, and then the forge keeps the remainder for their fee. You can'...


17

A wallet is the collection of data needed in order to receive and spend bitcoins. Usually this includes key-pairs (private key, public key and the address that may be inferred from the public key) and funds associated with each key-pair in the form of spendable outputs. The client on the other hand is the interface to the network. It handles all the ...


16

This seems to be a few related questions in one, so I will try to rephrase them individually and answer each one separately. First it is important to understand that a wallet is just a place to keep bitcoin addresses, in the same way that a leather wallet is just a place to keep cards and notes. Bitcoin amounts are sent to an address, not to a wallet. A ...


16

Receiving addresses are addresses generated specifically for sharing with people to send payments to you. Change addresses are generated by your wallet automatically when you send funds to someone else. To understand how change addresses work, consider this example. Say you received 0.1 BTC once, and 0.2 BTC another time. Now you have two UTXOs (unspent ...


14

People had bitcoins loaded on Mt.Gox internal trading accounts (trading wallets). This goes both for fiat currency and bitcoins. Bitcoin withdrawals were shut-down for a few weeks now, which created concepts like "goxbucks" or "goxcoins" as you could not get any Bitcoins out. Now, the Mt.Gox is closed completely, so you cannot get either fiat currency or ...


14

"Improbable" is an understatement. There are 2256 possible keys. In the entire universe, there are estimated to be "only" 2100 atoms. So the odds of someone else ending up with the exact same address/key as you is far, far less than the same atom, out of the entire universe, being randomly picked twice. If you are worried about an address collision, here ...


13

A deterministic wallet is any wallet for which a given private key can be predictably recovered with just: the original secret seed the identifier / sequence number of the desired keypair There are two types of deterministic wallets: sequential deterministic wallets hierarchical deterministic wallets With a sequential deterministic wallet, the seed is a ...


13

There are three main types of wallets: non-deterministic (random) wallets sequential deterministic wallets hierarchical deterministic wallets With a non-deterministic (random) wallet, all the private/public keypairs are generated randomly. The wallet may generate 100 random private keys as soon as it is initialized, for example. With a sequential ...


13

As @Murch correctly pointed out it is indeed possible to send bitcoin to either a public key or to the hash of a public key. The original motivation for using hashes of public keys was to shorten the size of the address. Public keys in their uncompressed form are 64 bytes long whereas RIPE-MD outputs 20 bytes (+5 bytes of checksum and version). ...


13

Yes! The trick is to count each input with its effective value rather than its nominal value. Transactions are composed of three parts: the overhead, the inputs and the outputs. Outputs: The size of the output scripts is determined by the recipient addresses, so their size is given by the transaction instructions. We do not know whether we will need a ...


13

What stops malware from being malicious? Nothing What can you do to ensure that the wallet you are using is a secure way to access your bitcoin? Use an open source bitcoin wallet, download from the original source and verify authenticity before use. If you understand code, review and build it yourself. Obviously, if a person creates a wallet to steal bitcoin ...


12

Electrum is easier. Armory is harder. Electrum lean towards minimalism. Armory is aimed at power users. Even though you asked about offline wallets you will likely want to maintain a watch only version of your wallet on your online system to be able to see the current balance, create unsigned transactions and give out addresses to people who want to send ...


12

C++ may be viewed by some as more suitable for Bitcoin use than Java which I2P currently heavily relies upon https://github.com/monero-project/kovri Kovri: To cover, veil, wrap (Esperanto). A secure, private, untraceable C++ implementation of the I2P anonymous network. Once complete this project should ease of integrating Bitcoin in both a private and ...


12

If you are missing the first word and you know the rest of the 11 words, there are 2048 possible mnemonics but only ~128 of them are valid. Using Python and this library you can print all the valid ones with this simple script: from cryptotools.BTC.HD import check, WORDS phrase = "{x} decrease enjoy credit fold prepare school midnight flower wrong ...


12

Can I get short a explanation about cryptocurrency cold/hot wallets? Hot wallets These are any kind of wallet that has a network connection and so is vulnerable to attack and is relatively unsafe. Many people prefer to keep their savings in a cold-wallet and only transfer money to a hot-wallet when they need to spend the money. You need a hot-wallet to send ...


11

You don't want to be storing any funded keys server side, there's an almost constant steam of hosts being compromised to steal funds. Most Bitcoin systems use something called a "hot wallet", and move the rest onto individual paper wallets outside of the servers control. It's then the administrators role to move funds back and forth to keep the hot wallet ...


11

You can use Blockchain.info. Just paste the address you want to check into the Search inputbox and the website will show you all the transactions where that address was involved, as well as the balance.


11

When you create a private key, this process is (or at least should be) completely random - meaning that in theory, the probability of creating some specific private key is 1/N where N is the number of possible private keys. There's nothing stopping someone from creating an already created private key, except chance. A private key is made up of 256 ...


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