Blockchain on Janik von Rotz

Create a soft wallet and transfer your Ether coins from an exchange

Wed, 10 Jan 2018 14:58:27 +0000

Intrigued by the title you might ask your self: What is the reason to store ether in a software wallet? Well, If you have cryptocoins on an exchange platform there is always the risk of the account getting hacked or the platform goes offline (see MtGox). Exchange platforms for cryptocoins are not as regulated and institutionalized as banks and trading centers are. The risk is in favor of the provider. To assert full control of your coins aka your money it is recommended to store them in a wallet.

In the following tutorial I will show you how I have transferred my coins into a soft wallet.

This tutorial assumes that the os environment is MacOS. Nonetheless, the platform does not matter to go through the tutorial, it also works for other platforms such as Windows or Linux.

Install Geth

Lets get started by installing the go command line tool to interact with the Ethereum network.

Use Homebrew to install the tool, make sure it is up-to-date.

brew update
brew upgrade

Install the go etherum cli.

brew tap ethereum/ethereum
brew install ethereum

For other platforms use the according package manager.

Account Management

To receive Ether we need an account.

Create an account and set a password.

geth account new

Make sure to store the password somewhere safe. There is no way to retrieve or reset the password for the account once lost.

List all available accounts.

geth account list

Backup the keystore file of the new account.

cp ~/Library/Ethereum/keystore/UTC--yyyy-mm-ddT12-59-07.353801000Z--927b07ac62ee6c10861b5024710a997937b20e31 /path/to/encrypted/storage/Etherum/_ADDRESS_.prv

Sync

Transactions are stored on the block chain. In order to see transactions and execute them you must sync the blockchain.

Sync the Etherum blockchain in fast mode.

geth --syncmode fast --cache 2048

This mode allows us to sync the blockchain without processing and verifying each block.

The second parameter sets the cache according to the computers available memory. Make sure to adjust the number.

To see the progress of the sync an attached geth console must be started. An attached geth console is connected to the currently running geth process. Open a new terminal and run the command below.

geth attached

Now check the syncing state.

eth.syncing

As long as the current and highest block number do not match, further syncing is required.

Send Ether

Once the sync is finished, we are ready to retrieve Ether.

From your exchange platform (I am using Kraken) send the fewest amount of Ether possible to the accounts address. Do not send all of your Ether. We have to make sure everything works correctly.

To see the transaction a sync of the chain is required.

To check the accounts balance start the geth console.

geth console

Now run this JavaScript code.

function checkAllBalances() {
    var totalBal = 0;
    for (var acctNum in eth.accounts) {
        var acct = eth.accounts[acctNum];
        var acctBal = web3.fromWei(eth.getBalance(acct), "ether");
        totalBal += parseFloat(acctBal);
        console.log("  eth.accounts[" + acctNum + "]: \t" + acct + " \tbalance: " + acctBal + " ether");
    }
    console.log("  Total balance: " + totalBal + " ether");
};
checkAllBalances();

The JavaScript function return the Ether balance for each registered account.

If you see a positive Ether balance for your account then everything works fine and you are ready to send more Ether to the soft wallet.

Secure Storage

In case you want to know how I store my password and key files.

I am using the keybase file system to store the key file of the geth account and KeePass to store the password. The KeePass database is encrypted with a password and a key file. All data can be accessed from my Windows and from my Mac computer. These tools are all open source. Further the hard disk of my Windows and Mac computer are encrypted.

Geth Alternative

In case geth did not work you, try parity.

Source

Etherum Wiki - Managing your accounts
Etherscan - Blockchain Explorer

My Dogecoin experience: mining server

Fri, 30 May 2014 14:07:11 +0000

In my last post I’ve written about the hardware components I’ve bought for my dogecoin mining server. This time I show you the finished mining rig and summarize the most important configurations for the mining software.

My mining rig

Your browser does not support the video tag.

Basic Setup

This tutorial assumes you have the following setup:

Windows 7 Service Pack 1
3 x Asus R9 270x graphics card

Download and install the latest version of:

cgminer by ckolivas AMD Catalyst driver

In case to this cgminer won’t work, try this one:

cgminer by kalroth

To monitor the cpu and ram usage of the server I’ll use the built-in resource monitor for windows.

Test Setup

After unziping the cgminer add a configuration file named cgminer.conf to the cgminer folder.

Add the following json configuration to config file, of course you have to replace the pool credentials.

{
	"pools" : [
		{
			"url" : "stratum+tcp://www.suchcoins.com:3333",
			"user" : "weblogin.WorkerName",
			"pass" : "workerPassword"
		}
	],
	"scrypt" : true
}

Next add a batch cgminer.bat to the same folder and add this commands:

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
cgminer.exe

Finally double click the batch file. Cgminer should start to mine some coins.

Productive Setup

Now we are going to tweak our cgminer installation. For this purpose we have to add a bunch of parameters to our batch file.

cgminer Parameter

Thread Concurrency

–thread-concurrency is a parameter to tell your graphics cards how many different tasks it should be juggling at the same time. Depending on your card, this can be set for anything between 2-30,000. It may or may not help your performance, but most people set it between 10,000-25000.

GPU Overclocking Parameters

–gpu-memclock and –gpu-engine Allows you to specifically overclock your cards. If you don’t know the defaults off the top of your head, a quick way is to go into cgminer and Press G, it will take you to the graphics card details screen. E: would be your –gpu-engine and M: –gpu-memclock for GPU 1.

Intensity

-I A value between 1-20, this is a general setting that makes our graphics cards work harder. Putting it on 20 will put your cards into high speed. Intensity is usually the last parameter that you will set, after you tweak everything else.

Autofan and Temp Targets

–auto-fan gives cgminer more control on keeping your cards a specific temperature.

–temp-target 80 tells cgminer to keep your card around 80.

–temp-overheat 85
to help prevent overheating.

Work Size

-w is the parameter for Work Size, or the size of jobs your cards will be doing. Most people flag this at -256 to start for mid tier cards. But the effect this parameter is described as “minimal”.

-g This is labeled as an optional parameter that can give some small boost, but shouldn’t be be the first thing you go after. It seems to crash cgminer if it is set any higher than 4, and many people leave it at 1 or 2. Some people have gotten a lot more than others out of this.

My configurations

This is my first configuration approach: -I 18 -g 1 -s 265 --thread-concurrency 20000 --auto-fan Now each GPU runs with about 400kH/s. It’s not that much, I’ve seen others got about 450kH/s with the same hardware.

Source

http://linustechtips.com/main/topic/95726-r9-270x-485khs-setup https://litecoin.info/Mining_hardware_comparison http://www.minedogecoin.com/getting-such-dogecoin-a-basic-guide-to-gpu-mining-with-cgminer

My Dogecoin experience part 1 - Mining Hardware

Thu, 08 May 2014 09:24:46 +0000

Based on a internet meme and funded as a joke the Dogecoin crypto currency is getting really serious about their business.

Just for fun I’ve bought some computer hardware to mine some doges.

Here’s a list of hardware I’ve bought in case you’re also interest in this crypto currency mining stuff.

Digitec is my local retailer in switzerland, the type of hardware is almost the same.

Hardware

GPU

Cgminer is the simplest and most effective miner to use. That’s why you should buy a AMD GPU.

MSI Computer Corp. Video Graphics Card R9 270 GAMING 2G
This is a good GPU with an average performance. A good thing to start.
Amazon $184
Digitec 186.–

CPU

Processing speed of the CPU makes no difference for mining. We just need something that can run the operating system. Plus this CPU is actually good because it uses less power.

AMD Sempron 145 Processor (SDX145HBGMBOX)
Amazon $30

AMD Athlon II X3 455 (AM2+, AM3, 3.30GHz, Unlocked)
Digitec 67.-

CPU Cooler

Arctic Freezer 13 PRO (120mm)
Digitec 48.-

Power Supply

SeaSonic Platinum SS-860XP2 Power Supply
This is a really high quality power supply. The main benefit this has over other power supplies that are a little cheaper, is that the energy efficiency is much better than what others recommend (Being Platinum Rated). This will mean your electricity is much cheaper, and over the long run it will pay for itself.
Amazon $180
Digitec 200.–

Cooler Master V850 - 850W Power Supply with Fully Modular Cables and 80 PLUS Gold Certification
Amazon $169
Digitec 187.-

Motherborad

ASUS M5A97 R2.0 AM3+ AMD 970 SATA 6Gb/s USB 3.0 ATX AMD Motherboard
This motherboard is a good choice for being cheap and able to handle the 3 graphics cards (Up to 4 actually). But you will need powered extenders.
Amazon $88

ASUS M5A99X EVO R2 (AM3+, AMD 990X, ATX)
Digitec 138.–

Hard Drive

Just big enough for the OS. Since we are just using it for mining this will be fine.

ADATA USA Premier Pro SP600 2.5-Inch 64 GB SATA III MLC Internal Solid State Drive ASP600S3-64GM-C
Amazon $49
Digitec 57.-

Ram

All we need is 4gigs or so of ram. RAM has no impact on mining, we just need enough to run the OS. You might be able to pick up a stick for slightly cheaper, but this one is good and more consistently in stock.

Kingston Hyper X Blu 4 GB 1600MHz DDR3 Non-ECC CL9 Desktop Memory (KHX1600C9D3B1/4G)
Amazon $49

Corsair XMS3 (1x, 4GB, DDR3-1333)
Digitec 44.–

Riser Cables for Graphics Cards

The motherboard has 2 PCI-Express x16 and 2 1x slots. So you can go with 2 PCIE “1x-16″ risers and 1 PCIE “16x-16x” Riser or vice versa. I went with 1- x16 riser and 2 x 1 to 16 riser to reduce power usage through the motherboard. It is important for the 1x to 16x ones are powered, so that your motherboard isn’t overloaded. Risers are also necessary to help disperse heat.

Qody PCI-E Extension Cable: 1X to 16X (powered)
Amazon 5$

Micro SATA Cables - PCI-E Express 16X Riser Card with Flexible Cable
Amazon 8$

Case

Most miners go with a simple milk crate to hold their components.

Sterilite 16929006 Storage Crate, Black
Amazon $12

Wireless Card (optional)

Make sure the wireless card is PCI, not PCIE, so if you want to add another graphics card later, you won’t be using a PCIE slot by your wireless card.

TP-LINK TL-WN951N Wireless N300 Advanced PCI Adapter, 2.4GHz 300Mbps, Include Low-profile Bracket
Amazon $28

TP-LINK TL-WN851ND, n300 (PCI) Digitec 22.-

Software

I’ll recommand to install a Windows 7. Everything else required is opensource.

Source

http://www.minedogecoin.com/building-a-nice-dogecoin-mining-rig-for-1000-dollars/
http://www.minedogecoin.com/top-graphics-cards-in-stock/

Get the latest version of this list here: https://gist.github.com/447c906e16c2c8be5719