Category Archives: Cryptocurrency

Cryptocurrencies and blockchain technology has received significant attention at the ongoing Saint Petersburg International Economic Forum. The Russian Central Bank made an important announcement regarding its plans to introduce a national cryptocurrency during the event. The introduction of a national cryptocurrency comes at a time when Russia is mulling over the possibility of legalizing Bitcoin and other altcoins in the country. The plans to develop a national cryptocurrency was announced by Russian Central Banks Deputy Chairman, Olga Skorobogatova.

Skorobogatova was quoted by one of the leading Russian media outlets saying,

Regulators of all countries agree that its time to develop national cryptocurrencies, this is the future. Every country will decide on specific time frames. After our pilot projects, we will understand what system we could use in our case for our national currency.

The Russian Finance Ministry recently announced its intentions to introduce Bitcoin regulations, offering a legal status to cryptocurrencies. The move is completely opposite to the ministrys earlier stance which involved criminalizing the use and trade of Bitcoin and other cryptocurrencies.

Russias decision to legalize Bitcoin closely follows Japans latest move to recognize the cryptocurrency as a legally valid mode of payment. The Russian Central Banks decision to introduce a national cryptocurrency is similar to the proposals put forward by respective regulatory bodies in England, United States and others.

Governments can save a lot of taxpayers money and resources by adopting cryptocurrency as a legal tender. The use of cryptocurrency will eliminate the costs otherwise involved in printing, transporting and managing physical banknotes. At the same time, cryptocurrency adoption will further promote the adoption of cashless payment methods.

With the banking sector increasingly adopting blockchain technology, the transition between conventional monetary system involving physical currency to blockchain based electronic currency will be smooth. It is just a matter of time before other countries also start adopting a similar stance.

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Russia to Soon Get Its Own National Cryptocurrency - newsBTC

Forbes

The Benefits And Best Practices Of Branding Your Own Cryptocurrency Forbes In 2015, "Minecraft," one of the most popular online games now owned by Microsoft, announced that PlayMC, one of their servers, would be introducing their own cryptocurrency in order to teach children about the digital currency. It's a pretty smart ...

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The Benefits And Best Practices Of Branding Your Own Cryptocurrency - Forbes

Coinbase, a Bitcoin exchange, is in talks for what could end up being the largest funding round ever for such a company, according to sources. The company is tipped in talks with possible investors for a funding round that may see Coinbase valued at more than one billion dollars, a new milestone for the cryptocurrency market if it proves true. What is spurring such massive figures? The similarly massive and growing demand for Bitcoin and other cryptocoins.

Information about the alleged talks comes from the Wall Street Journal, which reports that it got word from people familiar with the matter. Per those sources, Coinbase has experienced a big uptick in trading and traffic over the last several weeks, something spurred by Bitcoins renewed and record valuation. As we previously reported, Bitcoins value climbed back to the thousand-dollar mark in January, then quickly eclipsed it, blowing past its previous record high.

Critics downplayed the news, saying the uprise in value was a bubble that would soon pop (and that remains a possibility), but that didnt stop people from buying Bitcoin. By March, the value of a single Bitcoin had exceeded the value of an ounce of gold for the first time, and investors both big and small took note.

Coinbases jump in traffic and trading is no doubt spurred heavily by the increased valuation, though the company was already dabbling in massive numbers by the turn of the year. Back in January, Coinbase announced that it had raised $75 million in funding from multiple big-name financial institutions, among them being USAA Bank and the NYSE.

Why are people flocking to Bitcoin and currencies like it over more traditional currency investments, such as gold and silver? Thats a tricky question to answer; indeed, there are multiple reasons people are spending their paper money on digital rather than metal, and some of them are more appealing to certain groups than others.

Bitcoin brings with it a promise of anonymity that is mostly unrivaled in the financial world, though that is slowly changing as the cryptocurrency grows in popularity. Such digital monies arent unfamiliar in the dark net markets, being a staple of Silk Road clones and other online stores where illicit goods flow. The currency isnt limited to underground worlds, though, having become a viable payment option for a slew of companies and vendors, including Dell and Microsoft.

As the digital currencys novelty wears off and its value grows, others are eyeing Bitcoin as a potential way to make money, as a bet against fiat currencies that may fluctuate more heavily or precious metals that, relatively speaking, arent seeing the same big jump in value. The fixed and highly transparent Bitcoin supply is one major element of appeal on the investment level, giving it a solid edge over gold and silver and other valuable items that dont have such a solid and predictable rarity.

While gold, as an example, is a rare item, Bitcoin is more rare and quite a bit safer, at least from a fluctuation point of view. With certain other potential investments, the risk of overproduction or other inflationary issues remains, whereas with Bitcoin theres a bottom of the barrel and everyone knows where it lies. Bitcoin is created in such a way that its value can be preserved, whereas gold is more volatile, and knowing this is comforting.

Of course, there are many reasons you may want to hold off on cryptocurrency investments, and theyre good ones. Weve already seen some digital currencies rise and fall, including most recently Dogecoin with all its related drama, and theres the ever-present short-term volatility investors have to contend with. On top of that, cryptocurrencies require a bit of tech savviness that some feel ill-prepared to offer, and likewise it is difficult to liquidate Bitcoin relative to other investments.

The fact stands, though, that many are choosing to buy their own bits of Bitcoin in the hopes that its value will grow, and many have already won big on these bets.

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Coinbase tipped at $1b valuation as demand for cryptocurrency soars - SlashGear

Cryptocurrency exchanges are always trying to cater to a larger crowd. To do so, they often have to launch some sort of promotional effort to entice users. Although it is fairly common for people to actively trade Bitcoin and cryptocurrencies across multiple exchanges, an extra incentive is always welcome. Below are three recent examples of such promotional efforts which are all quite appealing.

Although this promotion only ran for a few days, it was quite an interesting concept. More specifically, the Huobi exchange launched an effort during which traders who created Bitcoin or Litecoin transactions would earn free Ether. These incentives have been paid out every single at 6 PM local time. The campaign ran from May 27th until May 31st.

It is quite interesting to note this campaign was mainly designed to introduce the Ethereum trading market on the Huobi exchange, which launched late last week. By giving regular traders access to free Ethereum, Huobi ensured these people would continue to spend funds on the platform itself. It is a smart promotional effort, although it is unclear whether or not any traders held on to their ETH rewards.

The BTCC exchange has always been one of the largest in all of China. Now that the company has successfully resumed withdrawals, it is a good time to launch a promotional campaign. The company celebrates its 6th birthday on June 9, 2017. As a result, BTCC is giving away a free iPhone 7, iPad, and other prizes for the most active traders.

This competition launched on June 1st and run until the 9th. During this period, as well as the rest of June, there will be no fees for bank wire deposits. This latter promotion may entice more users to partake in the electronics giveaway as well. Cryptocurrency traders always like lower fees and a chance to win something for doing what they enjoy. A smart move by BTCC, that much is evident.

Perhaps the most notable promotion across all cryptocurrency exchanges hails from Japan. The local Bitbank exchange has announced their addition of XRP trading about a week ago. To commemorate this massive event, the company will issue $736,000 in undisclosed incentives to anyone who can improve XRP trading liquidity on the platform.

This promotional campaign will run from June 1st until September 1st. Everyone who ranks in the top 5 in XRP/JPY trading will receive $800 worth of XRP. These incentives will be issued every single day. No traders would say no to receiving free cryptocurrency, especially if it has the potential to appreciate in price. This particular campaign will undoubtedly affect XRP trading in Japan moving forward.

If you liked this article, follow us on Twitter @themerklenews and make sure to subscribe to our newsletter to receive the latest bitcoin, cryptocurrency, and technology news.

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Top 3 Recent Cryptocurrency Exchange Promotions - The Merkle

Cryptocurrency (digital currency) is taking off this year. New millionaires are being made almost daily as Ethereum, Bitcoin, Litecoin, Ripple, Stratis, and other cryptocurrencies reach all-time highs. It is becoming somewhat of a modern-day gold rush.

As I write this, Bitcoin's "market cap" is $37 billion, with a value of $2,281 per Bitcoin. For a coin that was once worth only pennies, Bitcoin investors have made serious money in the past few years.

Bitcoin might be the oldest, but it's not the only cryptocurrency on the block. In fact, the majority of people getting into cryptocurrency are flocking to Ethereum. Ethereum has had the most impressive gains this year after recently being the first cryptocurrency to be backed by major corporations such as Microsoft, Samsung, JPMorgan Chase, and others in what's being called the Enterprise Ethereum Alliance. Ethereum does for code and programming what Bitcoin did for financial transactions. For simplicity's sake, think of Ethereum like a more advanced and sophisticated Bitcoin backed and utilized by major corporations because of its technological advances and clear pathway to building a decentralized internet.

One Ether (Ethereum's crypto token) was worth as little as $12 earlier this year, but the cryptocurrency is now worth $228 per coin with a total market cap of $21 billion. Ethereum is slowly but surely making gains on Bitcoin's market cap. Many spectators believe that "the flippening" will happen sometime this year, in which Ethereum becomes the most valuable (market cap) cryptocurrency in the world, overtaking Bitcoin in total value (total number of coins times price per coin).

Ethereum isn't the only new coin on the block, but it is definitely the most promising. Others to watch that I will explain and write about in future articles include Ripple, Litecoin, Statis, and Siacoin. All these coins have something unique and technologically innovative about them.

Buying cryptocurrency is confusing for a lot of people. It's not a stock or a typical "investment." It's not like anything most people have ever seen or experienced. You don't get shares; instead you get digital coins or tokens. The coins are "better" than a paper dollar bill because they actually support a greater cause, as in Ethereum's case, to build a decentralized internet and host code and apps on a decentralized platform. And coins help "fuel" that cause, so to speak, without getting technical.

For most people in the U.S., Coinbase would be the easiest option to buy Ethereum, Bitcoin, or Litecoin (it doesn't support any others yet). After verifying your account, you can add a number of payment methods including credit or debit cards, U.S. bank accounts, or even wire transfers of funds. Other options for exchanges that will take U.S. dollars for coins are Kraken, and Gemini in the U.S. Typically you will need to verify your account with a driver's license and add other details to expand your buy limits. Since cryptocurrencies are "hard currencies," the exchanges don't want to risk getting ripped off, since you can't reverse a cryptocurrency transaction once it's done.

If you are looking for some of the newer coins that are making big movement but haven't made their way to the aforementioned exchange sites, you can look into Poloniex or Livecoin. You can transfer Bitcoin or Ethereum to these platforms from Coinbase and then exchange it for any other digital currency that you want.

If you are outside the U.S., here are a few options for exchanges that take your local currency: BTC Markets (Australia), Bitthumb or Coinone (Korea), CHBTC or Huobi (China), and QuadrigaCX (Canada.) You can find a full list on this page of where to buy Ethereum for your local currency.

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How to Buy Your First Cryptocurrency Coins (Ethereum, Bitcoin, Litecoin, and Ripple) - Inc.com

As the value of cryptocurrencies like Ethereum and Bitcoin surge to all-time highs, a new project in crypto space promises to innovate the scene with tradable cards based on the 4chan meme, Pepe the Frog, which rose to popularity during the 2016 US election.

Amid the civil crisis in Venezuela and the plummeting of the Bolvar, some of its more enterprising startups were among the first to hop onboard the cryptocurrency bandwagon to secure their financial safety through the Rare Pepe digital currency.

So what is the tradable Rare Pepe, exactly? Unlike Dogecoin or other joke cryptocurrencies that hold next to no value, the tradable Rare Pepe is built around the concept of tokens and digital asset collection.

The 4channers who first popularized the Rare Pepe meme designed variations of Pepea comic strip character by artist Matt Furiecame up with the idea that each of these Pepes was one-of-a-kind, and therefore rare. In 2011, an eBay prank submission collecting 1,200 Rare Pepes received a $99,166 bid before being removed from the platform.

The tradableRare Pepe builds on this concept and turns the joke into a reality. Issued as tokens on the bitcoin blockchain through Counterparty, user generated Rare Pepe collectible cards hold monetary value and are listed on a directory after inspection by administrators.

The assigned tokens tied to Rare Pepe cards are locked on the blockchain, meaning it isnt possible to alter their Bitcoin value. Each card is a one-of-a-kind digital asset.

In addition to their scarcity, tokens issued on Counterparty are tradable on the services Bitcoin exchange, so users who possess these tokens can trade the Rare Pepe cards directly without anyone else holding the cards. A variety of wallets are compatible with the tokens, allowing users to amass a collection of Rare Pepe cards.

The Venezuela-based game developer of Rare Pepe Party even assigned scores and RPG elements to each Rare Pepe card, incentivizing gamers to build decks of Rare Pepe cards to play online.

It draws from a similar cryptocurrency-based game, Spells of Genesis, a mobile game that gamifies digital assets. Prior to the rise of Rare Pepes, a rare Spells of Genesis card called the Satoshicard, sold for over 6 bitcoins in 2016. At the time, it was worth $3,700. Its now worth $14,100.

Rare Pepe Party and Spells of Genesis arent the only platform to make innovative use of cryptocurrency. The Book of Orbs was designed a collection book and wallet for Rare Pepe owners to collect and trade them on their phones.

As the players of Pokemon Trading Cards and Magic the Gathering grow up, tradeable Rare Pepes provide nerdy cryptocurrency traders actual reason to collect cards, make money, and have fun while theyre doing it. And unlike the paper-based cards, they cant be damaged or destroyed.

Rare Pepes may still seem like a joke in the mainstream, but as Coin and Peace argues on his Medium article, they have the potential to reinvent the concept of currency by providing them with additional, if only entertaining utility.

Ian Miles Cheong is a journalist and outspoken media critic. You can reach him through social media at@stillgray on Twitterand onFacebook.

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From 4Chan Meme to Real Currency: 'Rare Pepes' are Innovating Cryptocurrency - Heat Street

Forbes

Cryptocurrency Is A Bubble Forbes Bitcoin has gone off the dial in the last few weeks, hitting above $2,700 a coin. It has fallen back since, but the other cryptocurrencies have shot up in the aftermath. Anyone who rode the dotcom boom will recognise the symptoms: up like a rocket and ...

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Cryptocurrency Is A Bubble - Forbes

The bigger question is whether or not China can reclaim its status as cryptocurrency powerhouse.

Most people are well aware of the issues affecting Chinese cryptocurrency exchanges. Withdrawals have been unavailable for quite some time now. Luckily, it seems things are finally getting back on track for most platforms. Both OKCoin and BTCC are effectively resuming cryptocurrency withdrawals. Users can apply for higher daily limits as well. This is good news for Bitcoin in general, and the price has gone up ever since these services resumed.

A lot of Chinese cryptocurrency traders are pleased withdrawals are available again. It has taken most exchanges several months to provide this service. Earlier this year, the PBoC intervened and told exchanges they need to step up their AML requirements. As a result, cryptocurrency withdrawals were halted indefinitely. This did not bode well for Bitcoin and other cryptocurrencies.

It now appears the long wait is over. BTCC and OKCoin have reinstated the cryptocurrency withdrawal option. Users will need to adhere to specific limits, though. However, it is possible to increase limits through an application process. One Reddit user claims this process takes about 20 minutes, which is not too bad. This application process puts the user at a 20 Bitcoin withdrawal limit per day.

It is good to see Chinese exchanges resuming their regular operations. Not all of the platforms in the country have reinstated withdrawals, though. Slowly but surely, these platforms are getting back to operating at full strength. Interestingly enough, this news has allowed the Bitcoin price to go up in value once again. An intriguing turn of events, to say the least. It is unclear what this means for the long-term though.

The bigger question is whether or not China can reclaim its status as cryptocurrency powerhouse. Before the AML investigations, Chinese exchanges dominated the landscape in trading volume. Ever since, they have been surpassed by Japanese and Korean platforms. If China can compete with those platforms based on volume, things will get very interesting for Bitcoin. An exciting future lies ahead, that much is evident.

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BTCC Is Resuming Cryptocurrency Withdrawals Albeit Limits Are Part of The Process - newsBTC

The Coin

We are going to create a digital token. Tokens in the ethereum ecosystem can represent any fungible tradable good: coins, loyalty points, gold certificates, IOUs, in game items, etc. Since all tokens implement some basic features in a standard way, this also means that your token will be instantly compatible with the ethereum wallet and any other client or contract that uses the same standards.

If you just want to copy paste the code, then use this:

The token contract is quite complex. But in essence a very basic token boils down to this:

So let's start with the basics. Open the Wallet app, go to the Contracts tab and then Deploy New Contract. On the Solidity Contract Source code text field, type the code below:

A mapping means an associative array, where you associate addresses with balances. The addresses are in the basic hexadecimal ethereum format, while the balances are integers, ranging from 0 to 115 quattuorvigintillion. If you don't know how much a quattuorvigintillion is, it's many vigintillions more than anything you are planning to use your tokens for. The public keyword, means that this variable will be accessible by anyone on the blockchain, meaning all balances are public (as they need to be, in order for clients to display them).

If you published your contract right away, it would work but wouldn't be very useful: it would be a contract that could query the balance of your coin for any addressbut since you never created a single coin, every one of them would return 0. So we are going to create a few tokens on startup. Add this code before the last closing bracket, just under the mapping.. line.

Notice that the function MyToken has the same name as the contract MyToken. This is very important and if you rename one, you have to rename the other too: this is a special, startup function that runs only once and once only when the contract is first uploaded to the network. This function will set the balance of msg.sender, the user which deployed the contract, with a balance of 21 million.

The choice of 21 million was rather arbitrary, and you can change it to anything you want in the code, but there's a better way: instead, supply it as a parameter for the function, like this:

Take a look at the right column besides the contract and you'll see a drop down, written pick a contract. Select the "MyToken" contract and you'll see that now it shows a section called Constructor parameters. These are changeable parameters for your token, so you can reuse the same code and only change these variables in the future.

Right now you have a functional contract that created balances of tokens but since there isn't any function to move it, all it does is stay on the same account. So we are going to implement that now. Write the following code before the last bracket.

This is a very straightforward function: it has a recipient and a value as the parameter and whenever someone calls it, it will subtract the _value from their balance and add it to the _to balance. Right away there's an obvious problem: what happens if the person wants to send more than it owns? Since we don't want to handle debt in this particular contract, we are simply going to make a quick check and if the sender doesn't have enough funds the contract execution will simply stop. It's also to check for overflows, to avoid having a number so big that it becomes zero again.

To stop a contract execution mid execution you can either return or throw The former will cost less gas but it can be more headache as any changes you did to the contract so far will be kept. In the other hand, 'throw' will cancel all contract execution, revert any changes that transaction could have made and the sender will lose all ether he sent for gas. But since the Wallet can detect that a contract will throw, it always shows an alert, therefore preventing any ether to be spent at all.

Now all that is missing is having some basic information about the contract. In the near future this can be handled by a token registry, but for now we'll add them directly to the contract:

And now we update the constructor function to allow all those variables to be set up at the start:

Finally we now need something called Events. These are special, empty functions that you call to help clients like the Ethereum Wallet keep track of activities happening in the contract. Events should start with a capital letter. Add this line at the beginning of the contract to declare the event:

And then you just need to add these two lines inside the "transfer" function:

And now your token is ready!

If you aren't there already, open the Ethereum Wallet, go to the contracts tab and then click "deploy new contract".

Now get the token source from above and paste it into the "Solidity source field". If the code compiles without any error, you should see a "pick a contract" drop down on the right. Get it and select the "MyToken" contract. On the right column you'll see all the parameters you need to personalize your own token. You can tweak them as you please, but for the purpose of this tutorial we recommend you to pick these parameters: 10,000 as the supply, any name you want, "%" for a symbol and 2 decimal places. Your app should be looking like this:

Scroll to the end of the page and you'll see an estimate of the computation cost of that contract and you can select a fee on how much ether you are willing to pay for it. Any excess ether you don't spend will be returned to you so you can leave the default settings if you wish. Press "deploy", type your account password and wait a few seconds for your transaction to be picked up.

You'll be redirected to the front page where you can see your transaction waiting for confirmations. Click the account named "Etherbase" (your main account) and after no more than a minute you should see that your account will show that you have 100% of the shares you just created. To send some to a few friends: select "send", and then choose which currency you want to send (ether or your newly created share), paste your friend's address on the "to" field and press "send".

If you send it to a friend, they will not see anything in their wallet yet. This is because the wallet only tracks tokens it knows about, and you have to add these manually. Now go to the "Contracts" tab and you should see a link for your newly created contract. Click on it to go to its page. Since this is a very simple contract page there isn't much to do here, just click "copy address" and paste the contract address on a text editor, you'll need it shortly.

To add a token to watch, go to the contracts page and then click "Watch Token". A pop-up will appear and you only need to paste the contract address. The token name, symbol and decimal number should be automatically filled but if it's not you can put anything you want (it will only affect how it displays on your wallet). Once you do this, you'll automatically be shown any balance you have of that token and you'll be able to send it to anyone else.

And now you have your own crypto token! Tokens by themselves can be useful as value exchange on local communities, ways to keep track of worked hours or other loyalty programs. But can we make a currency have an intrinsic value by making it useful?

You can deploy your whole crypto token without ever touching a line of code, but the real magic happens when you start customizing it. The following sections will be suggestions on functions you can add to your token to make it fit your needs more.

All dapps are fully decentralized by default, but that doesn't mean they can't have some sort of central manager, if you want them to. Maybe you want the ability to mint more coins, maybe you want to ban some people from using your currency. You can add any of those features, but the catch is that you can only add them at the beginning, so all the token holders will always know exactly the rules of the game before they decide to own one.

For that to happen, you need a central controller of currency. This could be a simple account, but could also be a contract and therefore the decision on creating more tokens will depend on the contract: if it's a democratic organization that can be up to vote, or maybe it can be just a way to limit the power of the token owner.

In order to do that we'll learn a very useful property of contracts: inheritance. Inheritance allows a contract to acquire properties of a parent contract, without having to redefine all of them. This makes the code cleaner and easier to reuse. Add this code to the first line of your code, before contract MyToken {.

This creates a very basic contract that doesn't do anything except define some generic functions about a contract that can be "owned". Now the next step is just add the text is owned to your contract:

This means that all the functions inside MyToken now can access the variable owner and the modifier onlyOwner. The contract also gets a function to transfer ownership. Since it might be interesting to set the owner of the contract at startup, you can also add this to the constructor function:

Suppose you want the amount of coins in circulation to change. This is the case when your tokens actually represent an off blockchain asset (like gold certificates or government currencies) and you want the virtual inventory to reflect the real one. This might also be the case when the currency holders expect some control of the price of the token, and want to issue or remove tokens from circulation.

First we need to add a variable to store the totalSupply and assign it in our constructor function.

Now let's add a new function finally that will enable the owner to create new tokens:

Notice the modifier onlyOwner on the end of the function name. This means that this function will be rewritten at compilation to inherit the code from the modifier onlyOwner we had defined before. This function's code will be inserted where there's an underline on the modifier function, meaning that this particular function can only be called by the account that is set as the owner. Just add this to a contract with an owner modifier and you'll be able to create more coins.

Depending on your use case, you might need to have some regulatory hurdles on who can and cannot use your tokens. For that to happen, you can add a parameter that enables the contract owner to freeze or unfreeze assets.

Add this variable and function anywhere inside the contract. You can put them anywhere but for good practice we recommend you put the mappings with the other mappings and events with the other events.

With this code, all accounts are unfrozen by default but the owner can set any of them into a freeze state by calling Freeze Account. Unfortunately freezing has no practical effect, because we haven't added anything to the transfer function. We are changing that now:

Now any account that is frozen will still have their funds intact, but won't be able to move them. All accounts are unfrozen by default until you freeze them, but you can easily revert that behavior into a whitelist where you need to manually approve every account. Just rename frozenAccount into approvedAccount and change the last line to:

So far, you've relied on utility and trust to value your token. But if you want you can make the token's value be backed by ether (or other tokens) by creating a fund that automatically sells and buys them at market value.

First, let's set the price for buying and selling:

This is acceptable for a price that doesn't change very often, as every new price change will require you to execute a transaction and spend a bit of ether. If you want to have a constant floating price we recommend investigating standard data feeds

The next step is making the buy and sell functions:

Notice that this will not create new tokens but change the balance the contract owns. The contract can hold both its own tokens and ether and the owner of the contract, while it can set prices or in some cases create new tokens (if applicable) it cannot touch the bank's tokens or ether. The only way this contract can move funds is by selling and buying them.

Note Buy and sell "prices" are not set in ether, but in wei the minimum currency of the system (equivalent to the cent in the Euro and Dollar, or the Satoshi in Bitcoin). One ether is 1000000000000000000 wei. So when setting prices for your token in ether, add 18 zeros at the end.

When creating the contract, send enough ether to it so that it can buy back all the tokens on the market otherwise your contract will be insolvent and your users won't be able to sell their tokens.

The previous examples, of course, describe a contract with a single central buyer and seller, a much more interesting contract would allow a market where anyone can bid different prices, or maybe it would load the prices directly from an external source.

Everytime you make a transaction on ethereum you need to pay a fee to the miner of the block that will calculate the result of your smart contract. While this might change in the future, for the moment fees can only be paid in ether and therefore all users of your tokens need it. Tokens in accounts with a balance smaller than the fee are stuck until the owner can pay for the necessary fee. But in some usecases, you might not want your users to think about ethereum, blockchain or how to obtain ether, so one possible approach would have your coin automatically refill the user balance as soon as it detects the balance is dangerously low.

In order to do that, first you need to create a variable that will hold the threshold amount and a function to change it. If you don't know any value, set it to 5 finney (0.005 ether).

Then, add this line to the transfer function so that the sender is refunded:

You can also instead change it so that the fee is paid forward to the receiver by the sender:

This will ensure that no account receiving the token has less than the necessary ether to pay the fees.

There are some ways to tie your coin supply to a mathematical formula. One of the simplest ways would be to make it a "merged mining" with ether, meaning that anyone who finds a block on ethereum would also get a reward from your coin, given that anyone calls the reward function on that block. You can do it using the special keyword coinbase that refers to the miner who finds the block.

It's also possible to add a mathematical formula, so that anyone who can do math can win a reward. On this next example you have to calculate the cubic root of the current challenge gets a point and the right to set the next challenge:

Of course while calculating cubic roots can be hard for someone to do on their heads, they are very easy with a calculator, so this game could be easily broken by a computer. Also since the last winner can choose the next challenge, they could pick something they know and therefore would not be a very fair game to other players. There are tasks that are easy for humans but hard for computers but they are usually very hard to code in simple scripts like these. Instead a fairer system should be one that is very hard for a computer to do, but isn't very hard for a computer to verify. A great candidate would be to create a hash challenge where the challenger has to generate hashes from multiple numbers until they find one that is lower than a given difficulty.

This process was first proposed by Adam Back in 1997 as Hashcash and then was implemented in Bitcoin by Satoshi Nakamoto as Proof of work in 2008. Ethereum was launched using such system for its security model, but is planning to move from a Proof of Work security model into a mixed proof of stake and betting system called Casper.

But if you like Hashing as a form of random issuance of coins, you can still create your own ethereum based currency that has a proof of work issuance:

Also change the Constructor function (the one that has the same name as the contract, which is called at first upload) to add this line, so the difficulty adjustment will not go crazy:

Once the contract is online, select the function "Proof of work", add your favorite number on the nonce field and try to execute it. If the confirmation window gives a red warning saying "Data can't be execute" go back and pick another number until you find one that allows the transaction to go forward: this process is random. If you find one you will be awarded 1 token for every minute that has passed since the last reward was given, and then the challenge difficulty will be adjusted up or down to target an average of 10 minutes per reward.

This process of trying to find the number that will give you a reward is what is called mining: if difficulty rises it can be very hard to find a lucky number, but it will be always easy to verify that you found one.

If you add all the advanced options, this is how the final code should look like:

Scroll down and you'll see an estimated cost for deployment. If you want you can change the slider to set a smaller fee, but if the price is too below the average market rate your transaction might take longer to pick up. Click Deploy and type your password. After a few seconds you'll be redirected to the dashboard and under Latest transactions you'll see a line saying "creating contract". Wait for a few seconds for someone to pick your transaction and then you'll see a slow blue rectangle representing how many other nodes have seen your transaction and confirmed them. The more confirmations you have, the more assurance you have that your code has been deployed.

Click on the link that says Admin page and you'll be taken the simplest central bank dashboard in the world, where you can do anything you want with your newly created currency.

On the left side under Read from contract you have all the options and functions you can use to read information from the contract, for free. If your token has an owner, it will display its address here. Copy that address and paste it on Balance of and it will show you the balance of any account (the balance is also automatically shown on any account page that has tokens).

On the right side, under Write to Contract you'll see all the functions you can use to alter or change the blockchain in any way. These will cost gas. If you created a contract that allows you to mint new coins, you should have a function called "Mint Token". Select it.

Select the address where those new currencies will be created and then the amount (if you have decimals set at 2, then add 2 zeros after the amount, to create the correct quantity). On Execute from select the account that set as owner, leave the ether amount at zero and then press execute.

After a few confirmations, the recipient balance will be updated to reflect the new amount. But your recipient wallet might not show it automatically: in order to be aware of custom tokens, the wallet must add them manually to a watch list. Copy your token address (at the admin page, press copy address) and send that to your recipient. If they haven't already they should go to the contracts tab, press Watch Token and then add the address there. Name, symbols and decimal amounts displayed can be customized by the end user, especially if they have other tokens with similar (or the same) name. The main icon is not changeable and users should pay attention to them when sending and receiving tokens to ensure they are dealing with the real deal and not some copycat token.

Once you've deployed your tokens, they will be added to your list of watched tokens, and the total balance will be shown on your account. In order to send tokens, just go to the Send tab and select an account that contains tokens. The tokens the account has will be listed just under Ether. Select them and then type the amount of tokens you want to send.

If you want to add someone else's token, just go to the Contracts tab and click Watch token. For example, to add the Unicorn () token to your watch list, just add the address 0x89205A3A3b2A69De6Dbf7f01ED13B2108B2c43e7 and the remaining information will be loaded automatically. Click Ok and your token will be added.

Unicorn tokens are memorabilia created exclusively for those who have donated to the address 0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359 that is controlled by the Ethereum Foundation. For more information about them read it here

You just learned how you can use ethereum to issue a token, that can represent anything you want. But what can you do with the tokens? You can use, for instance, the tokens to represent a share in a company or you can use a central committee to vote on when to issue new coins to control inflation. You can also use them to raise money for a cause, via a crowdsale. What will you build next?

Visit link:
Create a cryptocurrency contract in Ethereum

Bitcoin and cryptocurrency exchanges often suffer from an increased amount of internet traffic. In most cases, this indicates a spectacular growth among users looking to buy and sell cryptocurrencies across the platform. However, a lot of companies also suffer from DDoS attacks, or that is what they claim, at least. Below are some exchanges who suffered from recent DDoS attacks.

The past year and a half have been filled with quite a few roadblocks for the Bitfinex exchange. The company was hacked and saw over the US$70m worth of Bitcoin getting stolen. Moreover, Bitfinex sometimes faces a DDoS attack which slows down services or makes the platform completely inaccessible. One of those attacks took place in February of 2017, and it caused issues for users for quite some time. Both the front-end and API access were all impacted by this severe attack.

Bitcoin and other cryptocurrencies have seen incredible growth in popularity over the years. This is especially true in India, where demand for Bitcoin continues to grow. In December of 2016, the Indian exchange platform was hit by a major DDoS attack, shutting down the website, mobile app, and API altogether. It took a few hours of work to get everything in order again, but services were resumed pretty quickly, all things considered.

One of the oldest Bitcoin exchanges is known as BTC-E. The popularity of this platform is not on par with most other trading platforms, but it is still often used by cryptocurrency enthusiasts. One week prior to the Coinsecure DDoS attack, BTC-E suffered from a similar fate. The website was inaccessible for quite some time, although the company successfully increased its DDoS mitigation countermeasures. Ever since that time, the platform has not been targeted again by the look of things.

Larger exchanges are more prone to attracting the wrong kind of people. Kraken, one of the worlds biggest exchanges, has seen its fair share of DDoS attacks over the years. One such attack took place about three weeks ago, forcing the site and API offline. Unfortunately, a lot of traders were affected by this outage, as margin orders were closed without users being able to make changes. Margin trading across centralized platforms is always a risk, though.

The service provided by Poloniex has degraded quite a bit these past few months. For some unknown reason, the platform is incapable of dealing with their alleged user growth. As a result, the available infrastructure gets flooded during times of heavy trading, and the company often blames this on DDoS attacks. Increased user growth and DDoS attacks are not the same thing, yet it is evident Poloniex simply cant keep up with traders.

This string of DDoS attacks has caused quite a few issues for people who use the platform. Margin traders have lost a fair chunk of money these past few weeks. Moreover, it seems the company is struggling with deposit and withdrawal delays since a few weeks as well. It is unclear if this situation can improve, but for the companys sake, we can only hope they pick up the pace a bit.

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Originally posted here:
Top 5 Cryptocurrency Exchanges hit by DDoS Attacks - The Merkle