Can you mine without transactions?

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This is essentially correct: the protocol leaves it up to the miner to decide which transactions to include in a block. There is no requirement for them to include any transactions at all, other than the "coinbase" transaction which specifies where to send the block reward.

However, most transactions have fees attached, which the miner can collect only by including those transactions in the block. So this gives the miner an incentive to include transactions if there are any outstanding.

Note that a block with no transactions does still contribute to the security of the currency: it increases the amount of hashing that an attacker would need to do to reverse a transaction recorded in a previous block. (They would have to produce a chain showing more work than the current one, including the work proved by the zero-transaction block.)

See also Does mining activity only exist if there are bitcoin...

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Today someone showed up on IRC suggesting a scheme for to improve the

ability of miners to mine without validation while including transactions

by shipping around an approximate sketch of the txins that were used by a

block.

I pointed out that what sounded like the exact same scheme had been
previously proposed by Anthony Towns over a year ago, that it turned out
that it didn't need any consensus changes, but also wasn't very attractive
because the actual transmission of the block (at least with FBRP or Fibre)
didn't really take any longer... And, of course, mining without validating
does a real number on SPV security assumptions.

But then realized the the conversation between Anthony and I was offlist.
So-- for posterity...

I think the most interesting thing about this thread is that it gives a
concrete proof that a restriction on collecting transaction fees does not
discourage...

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This article is part of our ongoing series of Support Team Tips, where we tackle some of the more prominent questions our support team receives. In this post, we cover possibly the most common question new users ask about bitcoin transactions: can you cancel or reverse my transaction?

The short answer to this question is no, we can’t cancel, reverse, or speed up bitcoin transactions.

You can’t reverse bitcoin transactions? Why not?

To elaborate further on why, we’ll provide some important information to explain how bitcoin works, and how it compares to other payment methods.

When bitcoin was created, it was introduced as a public, distributed peer-to-peer electronic cash system. And in order for bitcoin (the currency) to succeed without a third party like a bank to mediate, verify, and manage transactions, the concept of a block chain ledger was developed alongside the currency as a way to verify and track transactions and prevent fraud. Settlement with...

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Can my Bank in France reverse transactions without my consent? | Localbitcoins

Geeney

Three transactions totalling to €800 was reversed to a scammer who transferred the money earlier in the month. There was no attempt by the bank to contact me before reversing the money. I know in some countries the bank would have to stay out of such matters like reversals. Anyone know what is common practice among EU and in France? I rang them 5 times (once every day this week) and each time my account agent was either having lunch (at 12pm) or gone home (at 4pm!). Talk about stereotyping the French!

dinbits

(_and CIP and CDD _)

nagleatorcoin

From what I know SEPA payments can be reversed within 24 hours in the case of fraud, similarly with Faster Payments in the UK. Didn't think SEPA payments could be reversed without the bank owners consent after 24 hours.

scottemick

It's very odd for a reversal after all...

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Neediness has gotten a bad rap.

You shouldn’t need a man. You should be independent and self-sufficient. You should seek a partner to complement you, not complete you.

Those “shoulds” come from everywhere. Culture. Advice columns. Friends.

It’s not surprising that more and more women are afraid to come out and speak their hearts’ truest desires. They want relationships. They don’t feel complete when they go home to an empty apartment. They don’t want more girlfriends; they want that one special best friend who’s at their side for life.

Recently, the Dalai Lama co-authored an article in the New York Times[1] about the importance of being needed. He mentioned a study that found that elderly people who didn’t feel useful were at much greater risk of premature death. “Feeling superfluous,” he wrote, “is a blow to the human spirit.”

Today, men are feeling more superfluous than ever.

Modern superwomen don’t need them. Women can buy a house,...

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How to start?

It's easy and free to open an account. Click sign up, fill out the form and log in. Then you have to fund your account. Click balance in the main menu and deposit your favorite digital currencies.

How much does it cost? Are there any fees on outgoing transactions?

The only fees user pays is transaction fees. These fees are essensial so that transaction can be processed by the network without delays. Transaction fees may vary for different currencies and depends on the network state.

How many confirmations do incoming payments require?

Number of minimum required confirmations is different for every currency.

How many addresses can my account have?

Currently we allow to create only 1 address per currency.

How quickly are outgoing payments processed?

We make payment instantly, however transaction usually needs some time to gain minimal number of confirmations. Minimum confirmations required varies in...

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Easiest way to buy airtime, make payments & send money with your 'ATM' card

You even get bonus airtime when you top up your phone on any network.

With your Verve cards. From your Phone

Buy airtime for all networks Pay to DSTV, ipNX, Aero, Swift, Startimes. And more. Transfer money to bank accounts No need to register for a wallet!

Requirements:
Compatible with BB OS 5.0 higher. BIS, WiFi, Edge, or 3G connection required.

Requirements:
Requires Android 2.1 and higher. WiFi, Edge, or 3G network connection required.

Requirements:
Compatible with Windows Phone 8 or higher. WiFi, Edge, or 3G connection required.

Requirements:
Requires IOS 5.0 and higher. WiFi, Edge, or 3G network connection required.

Requirements:
WiFi, Edge, or 3G connection required.

Requirements:
Requires WiFi, Edge, or 3G network connection required.

Click below to try...
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I have an unconfirmed transaction and/or it is confirming super slow. What should I do?

Be patient and wait. The transaction should confirm within 5 days. If it does not, tell the sender to resend with a fee. Do not ship goods without at least 1 confirmation. Please do not ask for help; it will not speed up confirmations.

Blockchain.info says it should be confirmed by now, but it is still not confirmed!

Blockchain.info's confirmation time is just a guess. Confirmation times may vary wildly, so do not be concerned when your confirmation time is long. Sit tight and your transaction will confirm.

Their transaction prediction system is also extremely outdated. Anything more than about 50 satoshi per byte will show up as "Will be in the next block", when in reality the priority is much, much higher.

How can I speed up confirmation in the future?

Use a wallet with dynamic fees (most do nowadays) and use the recommended fee set by the wallet. For fastest...

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If you’re reading this post I assume that like many others, you sent a bitcoin transaction and was kind of confused as to why it’s still listed as “unconfirmed” or “pending” after a few hours or so.

I mean Bitcoin transactions are supposed to be instant right?

In this post I want to try and explain in a very basic way how a Bitcoin transaction works and why the fee that you attach to each transaction has a crucial role in how long it will take the transaction to go through the network.

Here’s what happens when you send Bitcoins to someone

Whenever you send someone Bitcoins, the transaction goes through different computers running the Bitcoin protocol around the world that make sure the transaction is valid. Once the transaction is verified it then “waits” inside the Mempool (i.e. in some sort of a “limbo” state).

It’s basically waiting to be picked up by a Bitcoin miner and entered into a block of transaction on the Blockchain. Until it is picked...

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EntityFramework

This is a .net ORM Mapper Framework from Microsoft to help you talking with your Database in an object oriented manner. Wikipedia

Database Transaction

A database transaction, by definition, must be atomic, consistent, isolated and durable. Database practitioners often refer to these properties of database transactions using the acronym ACID. Transactions in a database environment have two main purposes:

To provide reliable units of work that allow correct recovery from failures and keep a database consistent even in cases of system failure, when execution stops (completely or partially) and many operations upon a database remain uncompleted, with unclear status. To provide isolation between programs accessing a database concurrently. If this isolation is not provided, the program's outcome are possibly erroneous. Wikipedia

.NET Transactions

A .NET Transaction can be used in different ways by different frameworks to support...

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src/main/java/hello/Application.java

package hello; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class Application { public static void main(String[] args) { SpringApplication.run(Application.class, args); } }

@SpringBootApplication is a convenience annotation that adds all of the following:

@Configuration tags the class as a source of bean definitions for the application context.

@EnableAutoConfiguration tells Spring Boot to start adding beans based on classpath settings, other beans, and various property settings.

Normally you would add @EnableWebMvc for a Spring MVC app, but Spring Boot adds it automatically when it sees spring-webmvc on the classpath. This flags the application as a web application and activates key behaviors such as setting up a DispatcherServlet.

@ComponentScan tells Spring to look for other components,...

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Contents of Earn Bitcoins

Earn Bitcoins by accepting them as a means of...
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@pa2013 helpfully posted Alon's BitKey announcement from last week to the Bitcoin Reddit, which sparked an interesting discussion regarding whether or not you can safely trust BitKey to perform air-gapped transactions. I started responding there but my comment got so long I decided to turn it into a blog post.

Air-gaps are not enough

As the astute commenters on Reddit correctly pointed out, just because you are using an offline air-gapped computer doesn't make you safe:

For example an offline computer can have a tainted random number generator, modified to only feed you addresses that the attacker can sweep at a later point in time.

I agree 100%. There are many ways a tainted air-gapped system can betray you, including smuggling out your secret keys via covert channel (e.g., USB keys, high frequency sound, covert activation of Bluetooth/wifi chipset, etc.)

The good news is that:

Even if you assume BitKey is evil you can still use it to perform a...
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I've been talking for a while about MSDTC and transactions without explaining them. I know many of you reading this blog already know the terms, but some of the developers just entering the enterprise space don't know if they should care or not about these subjects.

MSDTC is an acronym for Microsoft Distributed Transaction Coordinator. As the name says, MSDTC is a Windows service providing transaction infrastructure for distributed systems. In this case, a transaction means a general way of structuring the interactions between autonomous agents in a distributed system. Each transaction is a state transformation with four key properties - the ACID properties: Atomic (all or nothing), Consistent (legal), Isolated (independent of concurrent transactions) and Durable (once it happens, it cannot be abrogated). There are different techniques that implement the ACID properties but the most known one is two-phase commit.

In other words, transaction...

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When mining began, regular off-the-shelf PCs were fast enough to generate bitcoins. That's the way the system was set up—easier to mine in the beginning, harder to mine as more bitcoins are generated. Over the last few years, miners have had to move on to faster hardware in order to keep generating new bitcoins. Today, application-specific integrated circuits (ASIC) are being used. Programmer language aside, all this means is that the hardware is designed for one specific task—in this case mining.

New faster hardware is being created by various mining start-ups at a rapid rate and the price tag for a full mining rig—capable of discovering new bitcoins on its own—currently costs in the ballpark of $12,000.

(Read more: How to make your email as stealth as Edward Snowden)

There is a way around such a hefty investment: joining mining pools. Pools are a collective group of bitcoin miners from around the globe who literally pool their computer power together to...

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