Aspx Phpsessid How to Make Lean Bitcoin

Bitcoin relies on cryptography to function, which is why it is sometimes called a cryptocurrency.

But what role does cryptography play in Bitcoin, and why is it needed? We'll begin with a short introduction to some necessary cryptography concepts (if they are familiar to you, you can just skip to “The Reasons Bitcoin Needs Cryptography” on page 137), and then we'll explore the specific cryptographic methods used in Bitcoin.

If you flipped to this chapter only because you wanted to know whether the cryptography used by Bitcoin is safe, you can rest easy knowing that Bitcoin uses only tried-and-tested cryptographic techniques: All of the cryptographic methods used by Bitcoin have been widely used in the past by governments and major corporations to secure financial, medical, and other sensitive information, as well as personal identification data.

In fact, the cryptography in Bitcoin could be described as boring,

simply because it relies on very conservative cryptographic algorithms.
But in some fields of study, such as accounting and dentistry, boring is good; in the case of Bitcoin, conservative and well-established cryptography helps make it more secure. The interesting part is what Bitcoin does
with cryptography.

Fortunately, as you'll see, although Bitcoin cryptography may be old hat to the experts, it is still immensely fascinating to a novice!

A Brief Cryptography Overview

Historically, cryptography was used to send secret messages when necessary to protect information. Messages were systematically scrambled, or encrypted,

in a way that hopefully only the recipient of the message knew how to
decrypt.
A well-encrypted message might be intelligible as battle plans to the intended recipient, but to anyone else it would just be a well-tossed word salad with a side order of alphabet soup. Historically, encryption and decryption were laborious tasks and were reserved only for secure clandestine communication (usually of a military or illicit romantic nature). With the advent of computers, which could do in milliseconds what used to take hours manually, cryptography is now used routinely by the masses to encrypt/decrypt very important (eg, financial) and not-so-important (eg, pay-per- view TV) communication. Perhaps surprisingly, the convenience and speed of computers has led to the adoption of cryptographic methods for more than just encrypting secret messages. Common examples include logging in to websites with a username and password combination and using a registration key to install software. Both use cryptographic methods, but no message encryption is involved in either case.

In addition to encrypting messages, modern cryptography is used to verify the validity of information (through cryptographic hash functions)

and to prove one's identity (through
digital signatures).
For example, without modern cryptography, you wouldn't be able to distinguish between two identical websites that both claimed to belong to your bank. One might be phony and run by thieves to steal your money. But only your bank's website can provide the correct digital signature. Before we explain how digital signatures and cryptographic hash functions work, let's explore one-way functions, a feature that both rely on.

One-Way Functions

One-way functions

are mathematical functions that make it easy to calculate an output based on the input but difficult to do the reverse. A precise mathematical definition of what is easy or difficult doesn't exist but depends on the complexity of the calculation and the effort required to solve it.

A typical example is called integer factorization,

which asks you to write an integer as the product of only prime numbers—for example, the factors of 6 are 2 and 3, which are both prime. Given the prime factors as input, it is easy to multiply them to produce an output integer, but the reverse is not true (at least for larger numbers). Given a large integer, finding its prime factors is very difficult. The only known methods involve systematically guessing different combinations of prime factors, but the amount of time required to find the right answer increases exponentially with the number of digits. Imagine trying to multiply 2 x 7 x 7 in your head. It is not that difficult to calculate the answer of 98; however, if you were given the number 98 and were required to find its prime factors, generating 2, 2, and 7 would be more difficult. A typical laptop can factor a 60-80 digit number in less than a second, but the required time grows exponentially: To factor a 300-digit number or greater would take a modern supercomputer decades.

Another one-way function, which is a bit more complicated but is commonly used in cryptography, involves the discrete logarithm.

Consider a set of integers <0, 1, 2, 3, .
, n
- 1> where
n
is a prime number and where we only use modular arithmetic with modulo
n:3
hour hand on a clock once it moves past 12; instead of pointing to 13, it starts over and points to 1. However, whereas clocks start over at the number one, the common convention among mathematicians is to start over at 0. So 3 + 6 = 9, but 3 + 6 (mod 7) = 2 because after reaching 7, the next three numbers are 0, 1, and 2.

Your own Bitcoin node - what is it and why?

A long time ago, I wrote an article in which I listed ways to open your own Bitcoin wallet. One way was to install your own full node. It's time to add details and understand how the node can be useful.

Storing money is a very complex and multifaceted issue, and storing bitcoins is also technically complicated. If ordinary money can be kept at home (where it can be stolen) or in a bank (which can go bankrupt), then bitcoins can be lost by entrusting them to an exchange (which can be hacked), a storage service site (similarly), you can lose a flash drive with private keys , the hard drive may die, and hackers may also come.

Abkhazia. Digital transformation

Wallets: The most Scammers' wallets are similar to regular online wallets - with one difference: they will not give you your own address, but will offer you a ready-made one, from which your money will leak to the scammers. Bloody Sunday in the cryptocurrency market

Türkiye bans the use of cryptocurrency to purchase goods and services

Interestingly, the peak in sales of digital currencies occurred in the first days after the dismissal of the head of the central bank of Turkey.

Fraudsters can lure Bitcoin users into pyramid schemes, pretending to be miners, wallet services and exchanges.

Node as a payment interface

Let's assume that we need a site where we can deposit and withdraw BTC. There should be no commissions other than general network commissions; input and output of any amount of currency should be supported.

Alien API

And then the dancing with tambourines begins. The most obvious solution, at first glance, is to use a third-party API. Many sites provide such solutions, for example here is a solution from blockchain.info. I used it several years ago, and here’s what I didn’t like (this was a long time ago, the situation could have changed now):

Problem 1. Transfer delays

To receive a payment, you must first contact (via API) the blockchain.info website, get a new address for receiving payment, give the address to the client, the client sends funds to this address - this is still a blockhain.info wallet (hereinafter referred to as BI). After some time, the scheduler transfers money from the wallet that the client transferred to the wallet that you specified... But not immediately. In some cases, BI waits for confirmations, in others it waits for small payments to add up to a certain amount, and only then BI calls a callback on your website, reporting that the funds have arrived.

I lost count of the number of times angry clients wrote to me personally asking: I transferred the money, there are already 10 confirmations, why the balance has not been replenished. In such cases, sometimes the client had to beg to wait, sometimes write to BI support, and, in especially advanced cases, the transfer could take up to THREE DAYS. This is a bit much even by Bitcoin standards. It is clear that the second time people did not send funds.

In addition, people do not send funds to unknown destinations; no one is stupid. A very common pattern is to send a small amount, 30 rubles, check whether it arrived or not, then withdraw it, check whether it was returned, how much commission was actually written off, etc. Obviously, if with 30 rubles such a story lasts for several days, how many nerves will be required when depositing/withdrawing a large amount?

Problem 2: Technical limitations

For each user I created my own address, but the first sign came when the number of users exceeded 1000. The interface simply stopped working - at that time no one expected that someone might need such a number, and after 999 JavaScript wallets I just crashed with an error on the site.

Okay, no problem, I continued to receive the data I needed through the API, and after some time I was faced with the fact that they began to reject me - the size of my data, taking into account the number of addresses and transfers, exceeded the permissible norms for them. They informed me about this and promised terrible punishment, after which I changed the mechanism - I started generating differently, I started using addresses again... But it’s not cool when you can’t do it the way you need.

Problem 3. Fatal

All the money, all the transfers and in general the whole history is stored somewhere there. It is of course clear that the whole history is stored in the blockchain anyway, but when I have a node, only I know which address is mine and which is not mine... And that these 10,000 addresses are all mine, although outwardly there is nothing in common with them. And all these translations were made to me or by me... I don’t want any site to log this, in general.

[email protected]

Many consider it to be something of a talent “given from birth.”
However, with proper motivation, this quality can be developed. The main thing is to set the task correctly.

To begin with, let’s define what “business acumen” is. This concept is far from unambiguous and, apparently, that is why there are a large number of its definitions.

We suggest taking the following as a basis: \"Excellent planning. Organization of work and accounts. The ability to force yourself to work. Originality of ideas."

There are many opinions about such a quality as “business acumen”. Many consider it to be something of a talent “given at birth.”

However, with proper motivation, this quality can be developed.

To begin with, let’s define what “business acumen” is. This concept is far from unambiguous and, apparently, that is why there are a large number of its definitions.

We suggest the following as a starting point: “Excellent planning. Organization of work and accounts. The ability to force yourself to work. Originality of ideas."

Use the following tips:

1. Plan and Execute. When there is a lot to do, planning can seem like a waste of time. How can you sit calmly at your desk in front of a piece of paper when you don’t get anything done anyway? In fact, devoting 10-15 minutes. of your morning planning time, you save much more time during the day. If it is more convenient for you, make a plan for the next working day after the end of the current working day. In any case, the to-do list must be thought out, things must be written down in a certain order, taking into account the degree of importance of each of them. This list should be in front of you throughout the working day.

2. If possible, do several things at once. If you can do two things at the same time, do so. For example, plan the order of all business trips together to determine the shortest route. Collect all the data about your business's financial needs and go to the bank once a week instead of twice. Maintain and constantly update the list of necessary stationery supplies and, once you are near the desired store, buy everything you need.

3. Let other people free you from unimportant problems. FedEx will take your order and deliver it. Many office equipment and office supplies suppliers offer free shipping on a certain order size. Companies involved in the repair and debugging of computer equipment send their employees directly to your office for a small additional payment to the total cost of solving the problem. Let other people deal with these issues, you can use the time saved on other things.

4. Ask for help. If you need to do a project that requires hours of mindless work, ask friends or family to help you out for pizza and soda water (or beer). Ask for all kinds of help: from the selection and installation of media packages to packaging and delivery of orders. With this approach, a project can be completed in one evening when it might otherwise take a whole week.

5. Keep records. It's so easy to leave messages and write down reminders on small pieces of paper and sticky notes. But then these pieces of paper and sticky notes fill your entire workspace. Instead, keep one large notebook with a spring at the top. Keep it on your desk near your phone. Take it with you on a business trip. Every day in the morning, write the date at the top of a new page and write your to-do list on the same page. In this notebook, write down all names and phone numbers.

If in a couple of months you suddenly want to contact that supplier who offers paper bags at an excellent price, you can find his contacts in this notebook. A customer who has been dying to purchase your products? Guess! And his contacts are in the same notepad. In such notebooks you can keep a history of your affairs. Plus, they will definitely come in handy during tax filing, when you need to remember all your business trips and meetings, down to the amount of travel expenses.

6. Take short breaks during the workday. If you work every day, including weekends, the law of diminishing returns will eventually kick in. Even if you love your job, your brain's capabilities are limited. Take at least one day a week to rest completely. Take short breaks from work every few hours, for example, during such a break you can drink a cup of coffee while watching what is happening outside the window, or take a short walk and free your head from unnecessary thoughts. After such a break, you will return to work with renewed vigor and be ready to continue working.

To achieve your goals, you need all the time you can find. These ideas are a good start. Perhaps your family members or friends also have some ideas, ask them for their suggestions. Read books on time management and articles on self-organization. One good idea can save you hours of time.

Prepared by PraktiK (based on open source materials)

In a study that surveyed 55 global business leaders, business acumen was identified as the most important competency area for global leaders. Php Select How to Start a Bitcoin Blog

Installation.

I’ll say right away that location is important for a node. Now it takes up more than 200GB and will continue to grow, because... contains the entire blockchain. Disk space, ironically, is now expensive, so it’s cheaper to take a server from an HDD, or even install it on a laptop at home and forward the port. I will tell you using the example of installation on a laptop on which Ubuntu Server LTS is installed.

Edit the /etc/bitcoin/bitcoin.conf file

The password and user must be very strong, 100 characters each! It's still money.

Create a directory for storing the blockchain (200GB for today). By default everything will go to /home

Add node startup to crontab after reboot

Add an alias so you don’t have to specify the config every time

To check, run

The most useful command at first - displays a list of available commands

With its help you can also learn how to use any of the presented commands. For example:

Of course, on the node you can not only check balances, but also generate new addresses for receiving money

Send money to recipient

Or a list of recipients (each with their own amount)

What’s more pleasant is accessing the node via the web (if you explicitly allow this in the config). Of course, we cannot forget about security, so you should ideally work through VPN channels, or at least limit access to the node via IP.

Bitcoin for Beginners: The Complete Guide

By installing it, you can receive and send bitcoins or other cryptocurrencies.

Possible duplicates found (read more...)

2. Anonymity. Neither transactions nor accounts are associated with any real-world entities. You receive bitcoins to what is called an address, which is a random string of about 30 characters. As a rule, it is possible to trace the flow of transactions, but the address does not necessarily have to be in any way connected with the real identity of the user.

Launching the API

Let's change the config and see what happens

The node is deployed on a machine with the address 192.168.88.244, and the address of the computer from which I work is 192.168.88.248. On a node, I allow connections only from it (and locally from the node itself, of course).

The node needs to be restarted (in the simplest case, reboot Ubuntu, or kill the bitcoind process and start it again by copying the command from crontab)

Now you can check the work - let's open it in the browser first

Hurray, the host is available, the API has been raised, but stupidly you can’t work through the browser, let’s write a small script to work with it.

If everything is done correctly, the result will be like this:

A couple more methods - ask for information about the current state of the blockchain and try to make a transfer

The output will look like this

Here's the actual code:

Done, it worked - the node is running and the script sends and receives data from it. Think of it as a payment gateway or something in your pocket. Another useful option that can be mentioned is walletnotify. You can enter it into the config. Like this:

Every time information about a transaction arrives at your node (someone sent you money or you sent it to someone), the /home/scripts/transaction.sh script will be called (it must be written, of course).

This script will receive a transaction as an input parameter. What you do with it is your choice. I used it this way - as soon as a transaction arrived, the script was triggered, writing this transmitted hash of the transaction to a file, as the most reliable means. The server daemon monitored the file, and if it found a fresh entry there, it transferred it to the database and checked it - i.e. called a node method that requested information about the transaction. If it was an incoming transaction, and this was the first mention of it, I looked at what address it came to, found the user with this payment address in the database at the address (I gave out the addresses) and informed him that the payment had been received and was awaiting confirmation.

Another parameter from the same series is blocknotify=/home/bitcoin/blocknotify.sh %s. Every time the block information is updated, it calls the script and passes it the block number. This is convenient to use to update information about confirmations. Those. if the block has changed, it means the miners have worked, we can check what is there based on our transactions.

More details about the commands can be found here (in English)

Bitcoin Miner is a virus that hunts for your hardware

We recently talked about Bitcoin mining. There are people who mine this “cryptocurrency” honestly, buy equipment, and there are people who do it with the help of others.

The other day, one user began to complain that his computer began to slow down a lot. After looking at the antivirus logs and the computer log, I noticed that a strange program was installed on his computer under the user profile IMG002 and began to load the processor. The user caught Miner Bitcoin. After conducting the analysis, I want to share with you what the user caught and how to deal with it.

Trojan.CoinMiner is a large family of Trojan viruses that have already infected millions of computers. Trojan.CoinMiner is an extremely dangerous Trojan horse that intrudes deeply into your system. The program enters the computer fraudulently and uses its capabilities for the owner's purposes. The main task of the Trojan is to mine cryptocurrency using other people's resources. You can download and install a Bitcoin miner by accident - the program often takes the form of a photograph or Word file. At the same time, the worm not only “pumps” resources from the computer, but also steals personal information, which can be even more dangerous for the user.

The Bitcoin miner program was created by people who set the task of connecting as many PCs as possible to work and increasing Bitcoin earnings. The attackers relied on the fact that many people use 10-20% of their “machines” resources. When mining cryptocurrency, more power is consumed - up to 80-100%. Today, every network user can turn into a miner without his knowledge. The only difference is that such a person will not receive a profit - it goes to the person who “infected” the computer. The PC itself turns into a cryptocurrency mining robot. The Bitcoin system rewards “miners” and provides 25 Bitcoins for one mined block as a bonus. Actually, thanks to the active activity of miners and the processing of ongoing transactions, the operability of the entire structure is ensured.

After downloading and installing the Bitcoin miner, the PC is loaded to its maximum. At the same time, the owner of the victim computer may not notice that someone is “downloading” the computer’s resources. It is not difficult to recognize a virus - the computer load factor increases several times. Moreover, “heavy” programs can be closed. The main task of an attacker who infects a computer is to make the crime less noticeable and force users to follow the insidious link. As soon as the program is downloaded, the capabilities of the PC become the property of the hacker. At the same time, a criminal can solve many problems, from mining cryptocurrency to collecting personal information.

By the way, the Miner Bitcoin Trojan is far from the only program of this kind. Before its appearance, antivirus programs were already able to find a lot of worms using PC resources for their own purposes. One of these is Badminer, a program that searched for information processing blocks in a PC and used them in cryptocurrency mining. A computer is not capable of mining Bitcoin on its own. But nothing is impossible for hackers. Computer scientists find hacked “machines” that have a history of mining cryptocurrency and send their viruses there. If an attacker manages to find the key to more than a million computers, then his costs (time and financial) are fully recouped.

Trojan.CoinMiner is a common name for all viruses of this type.

There are several other similar symptoms of how the virus enters your system:

- A random app is using almost 100% CPU

- Your computer starts to run slowly or freezes every time.

- All websites are taking longer to load than usual.

- Your computer or laptop is overheating, turn it off or restart.

Also, if your computer is infected, you can check this folder on your computer:

C:\Users(Your username)\AppDataRoaminghodl

C:\Users(Your username)\AppDataRoamingETH

C:\Users(Your username)\AppDataLocalEthash

The last directory can often take up several gigabytes on your computer. This virus can give remote access to your PC, so the creator of Trojan.CoinMiner can easily control your computer without you seeing anything.

You can often notice that you are infected with this virus if you see cmd.exe or Engine.exe (also known as - sgminer.exe or SGM.exe ) in the task manager. These processes load the processor to 100% and your computer starts to run slower or simply freezes for a short time.

And if we look in the task manager, we will see.

How do antiviruses react to this virus?

How to get rid of this infection?

The first step, of course, is to disconnect this computer from the network, but I did not have this opportunity because the computer is located far away, and I added the sites where the virus is breaking into the proxy server, thereby blocking its access.

Then I went to the nod 32 website to download nod 32

And we make a bootable USB flash drive. We talked about how to make a bootable USB flash drive in our lesson “Creating a bootable USB flash drive (Rufus).”

And we check the computer for viruses. NOD 32 copes with this task perfectly.

But there is another situation like mine, the computer is far away and there is no way, then in this case KVRT (Kaspersky Virus Removal Tool) will help us.

Unfortunately, I did not find the current version of the antivirus on the official website, so I followed another link and downloaded the current one

Due to the large number of files on the computer, the computer scan took a long time. But after checking and rebooting, the computer began to work stably.

Conclusion:

Network users should be careful when downloading and installing suspicious files, as well as when working with torrent clients. Otherwise, the computer may turn into a “robot” that only mines Bitcoins. I hope that we helped someone get rid of this virus and if you fall for the bait, you will know what to do.

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