Hello! My name is Inna Halahuz, I am a sales manager at Platinum, the largest listing service provider for the STO and ICO projects. We know all about the best and most useful STO and ICO marketing services.
By the way, we developed the best blockchain platform:
We also created the UBAI, the unique educational project with the best and most useful online courses. We not only share our knowledge but also help the best graduates to find a job! After finishing our courses you will know all about crypto securities, ICO and STO advertizing and best blockchain platforms.
What a Blockchain Wallet is? What is its purpose?
Find the answer after reading this article.
The public key is the digital code you give to someone that wants to transfer ownership of a unit of cryptocurrency to you; and a private key is what you need to be able to unlock your own wallet to transfer a unit of a cryptocurrency to someone else. The encoding of information within a wallet is done by the private and public keys. That is the main component of the encryption that maintains the security of the wallet. Both keys function in simultaneous encryption systems called symmetric and asymmetric encryption. The former, alternatively known as private key encryption, makes use of the same key for encryption and decryption. The latter, asymmetric encryption, utilizes two keys, the public and private key, wherein a message-sender encrypts the message with the public key, and the recipient decodes it with their private key. The public key uses asymmetric algorithms that convert messages into an unreadable format. A person who possesses a public key can encrypt the message for a specific receiver.
Methods of wallet access vary depending on the type of wallet being used. Various types of currency wallets on an exchange will normally be accessed via the exchange’s entrance portal, normally involving a combination of a username/password and optionally, 2FA (Two factor authentication, which we explain in more detail later). Whereas hardware wallets need to be connected to an internet enabled device, and then have a pin code entered manually by the user in possession of the hardware wallet in order for access to be gained. Phone wallets are accessed through the device on which the wallet application has been downloaded. Ordinarily, a passcode and/or security pattern must be entered before entry is granted, in addition to 2FA for withdrawals.
Satoshi Nakamoto built the Satoshi client which evolved into Bitcoin in 2009. This software allowed users to create wallets and send money to other addresses. However, it proved to be a nightmarish user experience, with many transactions being sent to incorrect addresses and private keys being lost. The MtGox (Magic the Gathering Online exchange, named after the original intended use of the exchange) incident, which will be covered in greater detail later, serves as a reminder of the dangers present in the cryptosphere regarding security, and the need to constantly upgrade your defenses against all potential hacks. The resulting loss of 850k BTC is a still unresolved problem, weighing heavily on the victims and the markets at large. This caused a huge push for a constantly evolving and improving focus on security. Exchanges that developed later, and are thus considered more legitimate and secure, such as Gemini and Coinbase, put a much greater emphasis on vigilance as a direct result of the MtGox hacking incident. We also saw the evolution of wallet security into the physical realm with the creation of hardware wallets, most notable among them the Ledger and Trezor wallets.
Types of Wallets & Storage Methods
The simplest way to sift through the dozens of cryptocurrency storage methods available today, is to divide them up into digital and non-digital, software and hardware wallets. There are also less commonly used methods of storage of private keys, like paper wallets and brain wallets. We will examine them all at least briefly, because in the course of your interaction with cryptocurrencies and Blockchain technology, it is essential to master all the different types of hardware and software wallets. Another distinction must be made between hot wallets and cold wallets. A hot wallet is one that is connected to the internet, and a cold wallet is one that is not. Fun fact: The level below cold storage, deep cold storage has just recently been implemented by the Regal RA DMCC, a subsidiary of an internationally renowned gold trading company licensed in the Middle East. After having been granted a crypto trading license, Regal RA launched their “deep cold” storage solution for traders and investors, which offers the ability to store crypto assets in vaults deep below the Almas Tower in Dubai. This storage method is so secure that at no point is the vault connected to a network or the internet; meaning the owners of the assets can be sure that the private keys are known only to the rightful owners.
Lets take a quick look at specific features and functionality of varieties of crypto wallets. Software wallets: wallet applications installed on a laptop, desktop, phone or tablet. Web Wallets: A hot wallet by definition. Web Wallets are accessible through the web browser on your phone or computer. The most important feature to recognize about any kind of web wallet, is that the private keys are held and managed by a trusted third party. MyEtherWallet is the most commonly used non-exchange web wallet, but it can only be used to store Ethereum and ERC-20 tokens.
Though the avenue of access to MEW is through the web, it is not strictly speaking a web wallet, though this label will suffice for the time being. The MEW site gives you the ability to create a new wallet so you can store your ETH yourself. All the data is created and stored on your CPU rather than their servers. This makes MEW a hybrid kind of web wallet and desktop wallet. Exchange Wallets: A form of Web Wallet contained within an exchange. An exchange will hold a wallet for each individual variety of cryptocurrency you hold on that exchange. Desktop Wallets: A software program downloaded onto your computer or tablet hard drive that usually holds only one kind of cryptocurrency. The Nano Wallet (Formerly Raiwallet) and Neon wallet for storage of NEO and NEP-5 tokens are notable examples of desktop wallets Phone Wallets: These are apps downloaded onto a mobile phone that function in the same manner as a desktop wallet, but actually can hold many different kinds of cryptocurrency. The Eidoo Wallet for storing Ethereum and its associated tokens and Blockchain Wallet which currently is configured to hold BTC, ETH and Bitcoin Cash, are some of the most widely used examples.
Hardware wallets — LedgeTrezoAlternatives
Hardware wallets are basically physical pathways and keys to the unique location of your crypto assets on the Blockchain. These are thought to be more secure than any variety of web wallet because the private key is stored within your own hard wallet, an actual physical device. This forcibly removes the risk your online wallet, or your exchange counter party, might be hacked in the same manner as MtGox. In hardware wallet transactions, the wallet’s API creates the transaction when a user requests a payment. An API is a set of functions that facilitates the creation of applications that interact and access features or data of an operating system. The hardware then signs the transaction, and produces a public key, which is given to the network. This means the signing keys never leave the hardware wallet. The user must both enter a personal identification number and physically press buttons on the hardware wallet in order to gain access to their Blockchain wallet address through this method, and do the same to initiate transfers.
Possibly the safest form of cryptocurrency storage in terms of avoiding hacking, Paper Wallets are an offline form of crypto storage that is free to set up, and probably the most secure way for users, from beginners to experts, to hold on to their crypto assets. To say it simply, paper wallets are an offline cold storage method of storing cryptocurrency. This includes actually printing out your public and private keys on a piece of paper, which you then store and save in a secure place. The keys are printed in the form of QR codes which you can scan in the future for all your transactions. The reason why it is so safe is that it gives complete control to you, the user. You do not need to worry about the security or condition of a piece of hardware, nor do you have to worry about hackers on the net, or any other piece of malware. You just need to take care of one piece of paper!
Real World Historical Examples of Different Wallet Types
Web Wallet: Blockchain.info Brief mechanism & Security Blockchain.info is both a cryptocurrency wallet, supporting Bitcoin, Ethereum and Bitcoin cash, and also a block explorer service. The wallet service provided by blockchain.info has both a Web Wallet, and mobile phone application wallet, both of which involve signing up with an email address, and both have downloadable private keys. Two Factor Authentication is enabled for transfers from the web and mobile wallets, as well as email confirmation (as with most withdrawals from exchanges). Phone Wallet: Eidoo The Eidoo wallet is a multi-currency mobile phone app wallet for storage of Ethereum and ERC-20 tokens. The security level is the standard phone wallet level of email registration, confirmation, password login, and 2 factor authentication used in all transfers out. You may find small volumes of different varieties of cryptocurrencies randomly turning up in your Eidoo wallet address. Certain projects have deals with individual wallets to allow for “airdrops” to take place of a particular token into the wallet, without the consent of the wallet holder. There is no need to be alarmed, and the security of the wallet is not in any way compromised by these airdrops.
The NEON wallet sets the standard for web wallets in terms of security and user-friendly functionality. This wallet is only designed for storing NEO, Gas, and NEP-5 tokens (Ontology, Deep Brain Chain, RPX etc.). As with all single-currency wallets, be forewarned, if you send the wrong cryptocurrency type to a wallet for which it is not designed, you will probably lose your tokens or coins. MyEtherWallet My Ether Wallet, often referred to as MEW, is the most widely used and highly regarded wallet for Ethereum and its related ERC-20 tokens. You can access your MEW account with a hardware wallet, or a different program. Or you can also get access by typing or copying in your private key. However, you should understand this method is the least safe way possible,and therefore is the most likely to result in a hack. Hardware: TrezoLedger Brief History Mechanism and Security A hardware wallet is a physical key to your on-chain wallet location, with the private keys contained within a secure sector of the device. Your private key never leaves your hardware wallet. This is one of the safest possible methods of access to your crypto assets. Many people feel like the hardware wallet strikes the right balance between security, peace of mind, and convenience. Paper Wallet Paper wallets can be generated at various websites, such as https://bitcoinpaperwallet.com/
. They enable wallet holders to store their private keys totally offline, in as secure a manner as is possible.
Real World Example — Poor Practices
MtGox Hack history effects and security considerations MtGox was the largest cryptocurrency exchange in the world before it was hacked in 2014. They were handling over 70% of BTC transactions before they were forced to liquidate their business. The biggest theft of cryptocurrency in history began when the private keys for the hot wallets were stolen in 2011 from a wallet.dat file, possibly by hacking, possibly by a rogue employee. Over the course of the next 3 years the hot wallets were emptied of approximately 650000 BTC. The hacker only needed wallet.dat file to access and make transfers from the hot wallet, as wallet encryption was only in operation from the time of the Bitcoin 0.4.0 release on Sept 23rd 2011. Even as the wallets were being emptied, the employees at Mt Gox were apparently oblivious to what was taking place. It seems that Mt Gox workers were interpreting these withdrawals as large transfers being made to more secure wallets. The former CEO of the exchange, Mark Karpeles, is currently on trial for embezzlement and faces up to 5 years in prison if found guilty. The Mt Gox hack precipitated the acceleration of security improvements on other exchanges, for wallets, and the architecture of bitcoin itself. As a rule of thumb, no small-to-medium scale crypto holders should use exchange wallets as a long-term storage solution. Investors and experienced traders may do this to take advantage of market fluctuations, but exchange wallets are perhaps the most prone to hacking, and storing assets on exchanges for an extended time is one of the riskiest ways to hold your assets.
In a case strikingly similar to the MtGox of 2011–2014, the operators of the BitGrail exchange “discovered” that approximately 17 million XRB ($195 million worth in early 2018) were missing. The operators of the exchange were inexplicably still accepting deposits, long after they knew about the hack. Then they proceeded to block withdrawals from non-EU users. And then they even requested a hard fork of the code to restore the funds. This would have meant the entire XRB Blockchain would have had to accept all transactions from their first “invalid” transaction that were invalid, and rollback the ledger. The BitGrailexchange attempted to open operations in May 2018 but was immediately forced to close by order of the Italian courts. BitGrail did not institute mandatory KYC (Know your customer) procedures for their clients until after the theft had been reported, and allegedly months after the hack was visible. They also did not have 2 factor authentication mandatory for withdrawals. All big, and very costly mistakes.
Case Study: Good Practice Binance, the Attempted Hack
During the 2017 bull run, China-based exchange Binance quickly rose to the status of biggest altcoin exchange in the world, boasting daily volumes that surged to over $4 billion per day in late December. Unfortunately, this success attracted the attention of some crafty hackers. These hackers purchased domain names that were confusingly similar to “binance.com”. And then they created sufficiently convincing replica websites so they could phish traders for their login information. After obtaining this vital info, the scammers created API keys to place large buy orders for VIAcoin, an obscure, low volume digital currency. Those large buy orders spiked VIA’s price. Within minutes they traded the artificially high-priced VIA for BTC. Then they immediately made withdrawal requests from the hacked BTC wallets to wallets outside of the exchange. Almost a perfect fait accompli! But, Binance’s “automating risk management system” kicked in, as it should, and all withdrawals were temporarily suspended, resulting in a foiled hacking attempt.
Software Wallets Web/Desktop/Phone/Exchange Advantages and Limitations
As we said before, it is inadvisable to store crypto assets in exchange wallets, and, to a lesser extent, Web Wallets. The specific reason we say that is because you need to deliver your private keys into the hands of another party, and rely on that website or exchange to keep your private key, and thus your assets, safe. The advantages of the less-secure exchange or web wallets, are the speed at which you can transfer assets into another currency, or into another exchange for sale or for arbitrage purposes. Despite the convenience factor, all software wallets will at some point have been connected to the internet or a network. So, you can never be 100% sure that your system has not been infected with malware, or some kind of keylogging software, that will allow a third party to record your passwords or private keys. How well the type of storage method limits your contact with such hazards is a good way to rate the security of said variety of wallet. Of all the software wallets, desktop and mobile wallets are the most secure because you download and store your own private key, preferably on a different system. By taking the responsibility of private key storage you can be sure that only one person has possession of it, and that is you! Thereby greatly increasing the security of your crypto assets. By having their assets in a desktop wallet, traders can guard their private key and enjoy the associated heightened security levels, as well keep their assets just one swift transfer away from an exchange.
Hardware Wallets Advantages and Limitations
We briefly touched on the features and operation of the two most popular hardware wallets currently on the market, the Ledger and Trezor wallets. Now it will be helpful to take a closer look into the pros and cons of the hardware wallet storage method. With hardware wallets, the private keys are stored within a protected area of the microcontroller, and they are prevented from being exported out of the device in plain text. They are fortified with state-of-the-art cryptography that makes them immune to computer viruses and malware. And much of the time, the software is open source, which allows user validation of the entire performance of the device. The advantages of a hardware wallet over the perhaps more secure paper wallet method of crypto storage is the interactive user experience, and also the fact that the private key must at some stage be downloaded in order to use the paper wallet. The main disadvantage of a hardware wallet is the time-consuming extra steps needed to transfer funds out of this mode of storage to an exchange, which could conceivably result in some traders missing out on profits. But with security being the main concern of the vast majority of holders, investors and traders too, this slight drawback is largely inconsequential in most situations.
Paper Wallets Advantages and Limitations
Paper wallets are thought by some to be the safest way to store your crypto assets, or more specifically, the best method of guarding the pathways to your assets on the Blockchain. By printing out your private key information, the route to your assets on the Blockchain is stored 100% offline (apart from the act of printing the private key out, the entire process is totally offline). This means that you will not run the risk of being infected with malware or become the victim of keylogging scams. The main drawback of using paper wallets is that you are in effect putting all your eggs in one basket, and if the physical document is destroyed, you will lose access to your crypto assets forever.
Key things to keep in mind about your Wallet Security: Recovery Phrases/Private Key Storage/2FA/Email Security
Recovery phrases are used to recover the on-chain location for your wallet with your assets for hardware wallets like ledgers and Trezors that have been lost. When you purchase a new ledger for example, you just have to set it up again by entering the recovery phrase into the display and the lost wallets will appear with your assets intact. Private key storage is of paramount importance to maintain the safety of your on-chain assets! This should be done in paper wallet form, or stored offline on a different computer, or USB device, from the one you would typically use to connect to the 2 Factor Authentication (2FA) sometimes known as “two step authentication”. This feature offers an extra security layer when withdrawing funds from cryptocurrency wallets. A specialized app, most commonly Google Authenticator, is synced up to the exchange to provide a constantly changing code. This code must be entered within a short time window to initiate transfers, or to log into an exchange, if it has also been enabled for that purpose.
You must always consider the level of fees, or the amount of Gas, that will be needed to carry out the transaction. In times of high network activity Gas prices can be quite high. In fact, in December 2017 network fees became so high that some Bitcoin transactions became absolutely unfeasible. But that was basically due to the anomalous network congestion caused by frantic trading of Bitcoin as it was skyrocketing in value. When copying wallet addresses, double check and triple check that they are correct. If you make a mistake and enter an incorrect address, it is most likely your funds will be irretrievably lost; you will never see those particular assets again. Also check that you haven’t input the address of another one of your wallets that is designed to hold a different variety of cryptocurrency. You would similarly run the very great risk of losing your funds forever. Or, at the very least, if you have sent the wrong crypto to a large exchange wallet, for example on Coinbase, maybe you could eventually get those funds back, but it would still entail a long and unenjoyable wait.
How to Monitor Funds
There are two ways to monitor you funds and your wallets. The first is by searching for individual wallet addresses on websites specifically designed to let you view all the transactions on a particular Blockchain. The other is to store a copy of your wallet contents on an application that tracks the prices of all cryptocurrencies. Blockchain.info is the block explorer for Bitcoin, and it allows you to track all wallet movements so you can view your holdings and all the historical transactions within the wallet. The Ethereum blockchain’s block explorer is called Ether scanner, and it functions in the same way. There is a rival to Ether scanner produced by the Jibrel Network, called JSearch which will be released soon. JSearch will aim to offer a more streamlined and faster search method for Ethereum blockchain transactions. There are many different kinds of block explorer for each individual crypto currency, including nanoexplorer.io for Nano (formerly Rai Blocks) and Neotracker for NEO. If you simply want to view the value of your portfolio, the Delta and Blockfolio apps allow you to easily do that. But they are not actually linked to your specific wallet address, they just show price movements and total value of the coins you want to monitor.
That’s not all! You can learn how to transfer and monitor the funds in and out of your wallet by clicking on the link.
To be continued! UBAI.co
Contact me via Facebook, Instagram and LinkedIn to learn more about the best online education: LinkedIn Facebook Instagram
Let me say first that I've been following the drama closely and even invested into Verge and Mining it. I heard it all from Exit scams, 50% attack, to bashing on the Devs, to crypto posts. submitted by
Now let's put that junk behind us and look into a few things. So verge has signed a partnership with Pornhub.com, that's great news for Verge and Crypto in general. However, Crypto, as it stands right now, including Verge it a total mess of a payment system.
Now think as a everyday Joe, who wants to buy a Pornhub subscription with Verge, are they going to do all the necessary steps in order to do so? let's go through this
Step 1: Download a Wallet
Step 2: Get Verge from an Exchange
Step 3: Send Verge from exchange to wallet
Step 4: Send Verge from wallet to Pornhub
Step 5: Wait for confirmation of payment from Pornhub.
Now, lets break down these steps. Getting a wallet. Getting a wallet from XVG website is easy enough, however, it comes to a ZIP file with two programs. For the everyday user, an executable going to be far more familiar. Additionally, It took me 6 Days to sync my XVG Windows wallet. that's insane. I can get a Visa card and start using it right away. Now getting into the wallet. jesus What the hell? how do you send or receive? Assuming an average user, they have to watch a tutorial on all this. The Homepage, send, receive, block explorer, back-up wallet(which only gives you a wallet.dat file). How does one back-up a wallet, where does it go, how come I can't just go Back-up and restore from USB or external like windows? So at step one we already lost 90% of people who would want to use Verge or Crypto in general as useful payment system. It's just too complicated.
Then let's say they figure all that out and want to buy Verge, what exchange to they go to? Binance? Bittrex? Next we get into how does on even actually buy Verge? There currently is no USD/XVG pair. So far we basically trade for Bitcoin. So if a user wants to use Verge to pay for Pornhub. They have to buy bitcoin at an exchange then trade it assuming for market value. Prices fluctuate so insanely from BTC to XVG was $.11 now its $.07. This is beyond a shadow of a doubt why the idea of "Cryptocurrency" is beyond insane. It's been like this since bitcoin 2009, We cannot have a currency that is treated like a stock or investment which then fluctuates every single second. I understand Fiat currencies do similar for anyone who is invested into an ETF, but my one dollar is worth one dollar today, tomorrow, 5 years from now, 60 years from now. It's stable (Not taking into account Inflationary values). Going into this would be another write-up.
Which then leads us to another problem yet to be addressed is TAXES. A person buys Bitcoin then exchanges for Verge. Well, guess what. That's a taxable event according to the newest IRS law.
Exchanges are by far the biggest problem. Cryptocurrency need to get away from Exchanges. XVG would have to create/intergrated a payment system in their wallet, where on can buy a certain amount of XVG with USD, similar to how Video games in-game currency works buying weapons/Skins/Characters.
Now once they gotten their Verge, trying to Move Verge from wallets/Exchange involves COPY/PASTA. What average joe, who may know very little about computers, wants to potentially lose $20 because they didn't COPY/PASTA correctly? And’s not like those HEX values are easy to remember. I'm no Dev nor hold a CS degree but if they could make a 6-8 Digit number and behind that have that encrypted in HEX values that would be an idea.
Now they magically did everything correct and waiting for confirmations. That solely depends on the XVG network what happens if it gets overloaded like Bitcoin did in early 2018? or ETH in 2017 with Cryptokitties? Is this person going to wait 2 days for their Pornhub subscription because it hasn't been confirmed yet? Instant trasaction is something RAIBLOCKs/NANO amoung others is working on, additionally there whole another debate because of PoW like Verge and POS like ETH(wants to become).
I'm not hating on Verge, I'm not spreading FUD, this is a problem that all "cryptocurrencies" face. XVG Dev's have work cut out for them to make a more user-friendly wallet and transactions. But there is very little they can do to uncouple from BTC, Taxes, and simplify all that for the everyday users who just wants to watch porn!
7000 Bitcoins von Kryptogeldbörse Binance gestohlen Über kompromittierte Nutzeraccounts bei der Kryptogeld-Börse Binance sollen Unbekannte Bitcoin im Wert von rund 36 Millionen Euro geklaut haben. Electrum ist eine leichtgewichtige Bitcoin-Wallet für Mac, Linux und Windows. Electrum wurde im November 2011 entwickelt. Die Hauptfunktionen von Electrum sind: Support für Hardware-Wallets (wie z.B. TREZOR, Ledger Nano und KeepKey) und eine sichere Bitcoin-Speicherung durch die Nutzung eines Offline-Computers. Electrum ist eine gute Option für Anfänger und erfahrene Benutzer. Blockstream ... Binance Coin (BNB) Wallet. Manage your BNB, Bitcoin, Ethereum, XRP and over 300 tokens in a single interface. For Bitcoin, Ethereum, and 300+ assets Edge - Crypto & Bitcoin Wallet iPhone- / iPad-App 1.17.4 Deutsch: Edge, der Nachfolger von Airbitz, ist ein Crypto-Wallet für iPhones und iPads. Sie können mit der App Bitcoin und andere ... Das Electrum Bitcoin Wallet ist verfügbar für: Windows XP, Windows Vista, Windows 7, Windows 8, Windows 10, OS X, Linux und darüber hinaus auch für Android Smartphones. Für iOs Smartphones empfiehlt sich das Edge Mobile Wallet. Diese Wallet bietet eine automatische Verschlüsselung. Wie das Electrum Wallet arbeitet es mit einem dezentralisierten Server-Netzwerk und funktioniert auch dann ... Electrum - Bitcoin Wallet 4.0.4 Englisch: Mit dem kostelosen Tool Electrum erhalten Sie eine Bitcoin Wallet für den PC. Bitcoin/Ethereum an Binance-Wallet senden und IOTA kaufen ... Wir zeigen, wie Sie in Windows eine IOTA Wallet erstellen. Wer sein Geld selbst verwalten möchte, statt es Bitfinex zu überlassen ... Bitcoin Wallet Vergleich: Alles was man über Bitcoin Wallets wissen muss Auch wenn eine Investition in Bitcoins heutzutage immer einfacher wird, gilt es doch einige wichtige Informationen zu kennen. So sollte man als zukünftiger Anleger beispielsweise wissen, was ein Bitcoin Wallet ist, welche unterschiedlichen Arten es gibt, wie man ein Bitcoin Wallet erstellen kann und welche Anbieter am ...
To download PC wallet here: https://www.Exodus.io To create a Myetherwallet here: https://www.myetherwallet.com To Buy Bitcoins out of the middle east here: (these are all referral links that make ... Short video for those who need help creating API keys on Binance. This video is unavailable. Watch Queue Queue Bitcoin Golden-Cross Binance Hack FUD Ripple wie Amazon? Chainlink löst DeFi Problem Tezos Rakete IOTA Sicherheits Update 🔐 Bitcoin & Crypto Wallet... Today i'm going to review a multicoin wallet called Zelcore that is part of Zel Technologies which have their own coin called Zelcash and soon they are working on a ZelEx which is going to be ... Emergency Pod: A Glimpse at Facebook’s Libra Coin Binance CFO Wei Zhou walks you through the latest report by Binance Research on Facebook's long-anticipated... I’m not sure if calling this a hack is appropriate or even correct, which is why I have gone with a factual episode title. We won’t know the full story until they complete the security audit ... Binance'de İki adımlı doğrulama nasıl yapılır anlatmaya çalıştım. Faydalı olması dileğiyle Faydalı olması dileğiyle Binance Borsası Link'i (refli): Nova carteira trust da binance, mais uma opção para guardar suas criptomoedas com segurança no celular. Site http://bit.ly/2XCobu9 BTH Solutions http://bit.l... Bitcoin hack pro-2020 Bitcoin hack free Bitcoin wallet hack Bitcoin account hack Bitcoin address hack allbitcoin private keys Bitcoin hack in windows Bitcoin fast hack Bitcoin wallet blockchain hacked