Electrum 2.8 was just released, with improved fees and wallet file encryption.()submitted by π Rendered by PID 15091 on app-399 at 2017-06-24 12:20:16.286347+00:00 running 3522178 country code: SG.Locky Ransomware - Encrypts Documents, Databases, Code, BitCoin Wallets and More... Posted by on February 19, 2016Less Than 50 Lines of Code for a Password-Protected, Online Bitcoin WalletBuildling a full-blown Bitcoin Wallet like Blockchain.info is a time-consuming task (surprise, surprise), but with the help of a few JavaScript-libraries and the Blockchain.info-API, it’s possible to develop a Bitcoin Wallet with just a few lines of code.There are two features:Creating the Bitcoin address and encrypting the private key to receive Bitcoin.Sending Bitcoin from your address to an arbitray other address.As you may have thought before, it’s nearly useless.Except when you integrate Bitcoin functionality into your own application.The Itipu WalletItipu is a Bitcoin wallet operated in Facebook chat with the help of a chatbot.

The user’s funds are secured by a personal PIN code.Actually, the private key for the generated Bitcoin address is encrypted with this PIN code, so as long as the PIN code is safe, the Bitcoin are safe.bitcoin forum kursIn Itipu, you can send your Bitcoins to your friend’s wallet by telling the bot to do so, like, “Send 2 dollars to joe.” (You have to enter your PIN code of course).Sending money ?litecoin usd exchange rateNow there’s a bot for that!“send 2 dollar to joe” “Sent 2 USD to Joe Doe.bitcoin bits to btcJavaScript libraries to IncludeFor doing the Bitcoin-related stuff, I used the great “BitcoinJS”-library.bitfinex bitcoin

It depends on some other libraries as well, but as long as you use a package manager like npm, all of them will be loaded automatically.Furthermore, the “TripleSec”-library is used for cryptographic functions.Generating the Bitcoin walletFirst of all, load the libraries mentioned above.var=var=var=var=var=var=Next, the code to generate the address and encrypt the private key.functionvar=var=: new: newfunctionifelsevar=Of course, you have to figure out yourself what to do with the generated Bitcoin address and the encrypted private key.bitcoin mining 1 gh/sFor example, you can save it to a database linking it to the current user.Sending Bitcoin to Another AddressLoading the libraries is exactly the same as above.bitcoin pleaHere is the code to send the Bitcoin (actually: Satoshis) to another address: $.ajax({ // using Blockchain.info API to get unspent outputs url: 'https://blockchain.info/de/unspent?cors=true&active=' + address, type: 'GET' }).done(function(data) { var txHex = tx.build().toHex(); // pushing raw transaction to Blockchain.info API $.ajax({ url: 'https://blockchain.info/pushtx?cors=true', type: 'POST', data: 'tx=' + txHex }).done(function(data) {}Using the Blockchain.info-API this is almost a no-brainer.bitcoin hong kong regulation

The only tricky part is to calculate the transaction fee (“mining fee”) so that the transaction is not declined.Calculating the Mining FeeThe Blockchain.info formula is (currently):Minimum fee is 1.5 satoshi per byteSo I have to estimate the transaction size (in bytes) to calculate the mining fee.bitcoin script explainedThe formula is:#Inputs * 180 + #Outputs * 34 + 10 + #InputsTo be on the safe side, my wallet grants 2 Satoshi per byte.ConclusionThanks to public APIs and Open Source projects it’s pretty simple to provide Bitcoin functionality in your own applications.Shareethereum timelineA wallet backup protects your bitcoins against computer or software failure.It may also help you retrieve your funds after your device was stolen or lost.There are generally 3 ways to backup a Bitcoin wallet.Different software supports different methods.Make sure you're familiar with your wallet before loading it with bitcoins.If you lose the backup and can't access your wallet for some reasons, your bitcoins are permanently gone!

Remember: Always encrypt your wallet with a strong password to make it more difficult for an attacker to steal your coins!Wallet.datThis method is used by Bitcoin Core (and few others) and comprises of backing up a wallet.dat file.It's a file that holds keys to spend outputs, addresses, transaction information, and other metadata such as contacts.It has a different location based on an operating system.Windows: %APPDATA%\BitcoinLinux: ~/.bitcoin/Mac OS X: ~/Library/Application Support/Bitcoin/ If you can't find the location please refer to this page.BackupLocate wallet.dat and copy it to another device only you have an access to.It may be a USB drive, CD, another computer or your private home cloud storage.You may also copy it to a cloud storage such as Mega or Dropbox but make sure it's encrypted.Anyone that gets access to the unencrypted file will be able to steal your coins.Note: If you use Bitcoin Core make sure to backup wallet.dat file regularly after every ~100 transactions.

This way you make sure you have backup of all wallet and change addresses.RestoreTo restore the backup, simply copy your backed up wallet.dat over an existing one in the bitcoin data location.BIP 32BIP 32 is a method of determining key pairs from a single seed.This seed is used to generate a master private key (xprv) which then can be imported to any BIP 32 compliant HD wallet.To backup your wallet either copy the master key to a text file and back it up to another device (encrypted of course) or create a QR code, print it and store it somewhere safe (e.g.vault).If you decide to store the master key as a QR code make sure to disconnect from the internet.To restore the backup, simply paste the xprv string to your wallet when asked to.We won't go into details because most BIP 32 compliant wallets also support the next feature.If they don't, you may avoid using them.BIP 39BIP 39 describes a method of generating a mnemonic sentence - easy to remember set of words - that represents a seed which can be then used to determine wallet addresses (e.g.

BIP 32).When creating a wallet for the first time, you're presented with the list of seemingly random 12 to 24 words.The more the words the bigger the security.Some wallets like Trezor let you choose the entropy yourself.BackupWrite down the words on a piece of paper in an exact order and store it somewhere safe like a vault.You can split it to many papers and hide each piece somewhere else.As with the master private key, you may also want to print the words as a QR code.Note: If you have to store the mnemonic on your computer or a device connected to the Internet, make sure it's encrypted!RestoreTo restore the backup, open your wallet software and look for "New/Restore" feature in the menu.When prompted, type in the mnemonic from your paper in the exact order.The wallet will then determine the rest of your keys and addresses.It will also restore your transaction history from the blockchain but you won't see any metadata such as contacts or transaction labels.If you need them, you will have to backup a wallet data file too.