Random numbers using blockchain


Are they truly 100% random (generated by hardware) or is it pseudo-random (generated by software)?

Pedantic answer: No, they're not random, because the first twenty digits or so will always be zero.

Serious answer: The Bitcoin client does not use any hardware randomness, as far as I know. However, if even a single transaction in the block was generated using hardware randomness, the block hash will incorporate hardware randomness.

Also, I don't think you could predict the hash of a block that hasn't been found yet.

Can I rely on it or any other blockchain data to make a 100% trustable raffle?

As Greg said, a miner can withhold blocks if releasing them would make the miner lose the raffle. Of course, the cost of withholding a block and not broadcasting it to the network is about $9000, so this attack might not be useful.

How do I make a trustable raffle

Your method would probably work. This answer discusses how to exchange a...

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If I may answer with my stack overflow hat on...

Here's how I'd draw a random number in way that no participant can influence the result of.

Invite each player to pick a random number, x, and publish the hash(x). Once each hash has been published, each player should then reveal their x. With those x's, add them all together and hash the result. Use that final hash as the random value.

UPDATE: To work around the attack described in the comment below, use two rounds.

Each player selects a randon number, x, and reveals hash(x). When all hashes have been revealed, each player reveals x. All x's are combined and hashed. y=hash(all x) Each player selects a new random number, z, and reveals hash(y+z). When all of the second round of hashes have been revealed, each player reveals z. All z's are combined and hashed. The result is used as the random value.

If the player has a prepared hash collision, they could only use it to select their prefered y value. This...

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The magnitude and importance of random numbers in finance does not have to be explained. We need them. Either it is an option pricing or a Monte Carlo simulation, random numbers are with us. However, we make a trade-off: the speed in their generation versus uniqueness. That is why a widely accepted use of, inter alia, Mersenne Twister algorithm as a source of pseudo-random numbers has established its position as a leading PRNG.

Contrary to that, the use of true random numbers in finance is not so direct and obvious. We obtain truly unique randomness but at the expense of speed. Additionally, the (re)sources are limited what makes highly repetitive tasks hard to accomplish in a reasonable time. As discussed in my book on True Random Number Generators (TRNGs), the hardware solutions might be an appealing alternative. But they are expensive. The choice is yours.

If TRNs are so difficult to fetch, do we need them for financial applications? Interestingly, the answer...

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Total Membership Exceeds 150 Organizations in Less Than Seven Months
Cisco Systems, Scotiabank, Government of Andhra Pradesh Lead New Membership

NEW YORK, NY, USA – July 18, 2017 – Enterprise Ethereum Alliance (EEA) announced today that 34 organizations have joined the blockchain industry group since late May. This brings total membership to over 150 organizations added since the group’s launch in February of this year. EEA is now the world’s largest open-source blockchain initiative. EEA’s newest members represent a wide variety of business sectors, including technology, banking, government, healthcare, energy, pharmaceuticals, marketing, and insurance, as well as a number of fast-growing Ethereum startups.

Composed of forward-looking enterprises and blockchain innovators, EEA is an industry-supported, non-profit established to build, promote, and broadly support Ethereum-based technology best practices, open standards, and open source reference...

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It suddenly feels like blockchain is everywhere — and that includes media and advertising. Here’s what to know.

What it is
Blockchain is the technology that underpins cryptocurrencies like bitcoin; it’s essentially a massive Excel sheet that operates in a decentralized network format. That means that the data can have large amounts of information that can be transmitted and added onto, without compromising on security. You can’t change the blockchain — and for data purposes, not one person or entity can destroy it.

What it isn’t
Blockchain is not bitcoin. While that’s what it is best known for, bitcoin is basically a digital currency that operates on blockchain. The blockchain developed for bitcoin was developed specifically for it — which is why other uses for it were only developed much later. And while bitcoin works because it is anonymous, blockchain for other types of businesses don’t have to be anonymous. In fact, they shouldn’t be: Participants are...

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Another bug has been discovered in a bitcoin wallet, leading to the theft of around 50 bitcoins. This time, Blockchain.info's web wallet was at fault, and the company is now offering refunds to users who lost bitcoins due to the flaw.

The popular Blockchain website primarily offers market data and serves as the main block chain explorer for the bitcoin currency. However, users can also create web-based wallets to send and receive bitcoins. The bug lies in the random number generator that the web wallet uses to sign bitcoin transactions. The random numbers are generated in web browsers using the JavaScript programming language. It was discovered on Monday, when a bitcoin user reported that he had 1.8 BTC (around $223) stolen.

"Funds from other addresses in this wallet were not affected. This leads me on thoughts that Blockchain.info or Firefox may have some weakness in random number generator like the vulnerability was recently found in the Android, [sic]" he...

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To facilitate the possibility of upgrades and maintenance, and in exceptional circumstances to handle problems with ENS, the ENS root will initially be owned by a multisig, with members of the Ethereum dev community as keyholders. In the long term, we would like to see the root multisig replaced by some form of distributed decision making process, but developing such a process will require time, thought, and care, which we anticipate will be a longer term effort than the development of the permanent .eth registrar.

The current root keyholders are:

Aron Fischer Dan Finlay Nick Johnson Juan Benet Piper Merriam Taylor Monahan Vlad Zamfir

A majority of at least 4 of the 7 keyholders is required to effect any change to ENS.

All keyholders agree to act with the consensus of the community in facilitating the following ENS development activities:

Migrating the interim registrar to the permanent registrar once the evaluation period is over...
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Let’s face it, at times learning the ins and outs of Bitcoin when you’re a beginner can be daunting. Bitcoin at its core can be technical in nature (think of how technical it is to understand how the Internet works too) and for the layman, understanding its intricacies may prove difficult. Seeing the Blockchain address and transaction page for the first time may also be confusing. To make it easier to understand, we wanted to provide users with a breakdown of the Bitcoin addresses page, to help you understand exactly what it is you’re seeing and how to use it.

We’ll start top to bottom

We are using a random Bitcoin address pulled from a recent transaction in the blockchain as an example. Here is the URL: https://blockchain.info/address/134ZnmvWpGDGSwU6AnkgSEqP3kZ2cKqruh

On the upper left of the page, you will see the Summary section, which looks like this:

The Address is the Bitcoin public address. It is safe to share this with others. Never share...
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What's this fuss about true randomness?

Perhaps you have wondered how predictable machines like computers can generate randomness. In reality, most random numbers used in computer programs are pseudo-random, which means they are generated in a predictable fashion using a mathematical formula. This is fine for many purposes, but it may not be random in the way you expect if you're used to dice rolls and lottery drawings.

RANDOM.ORG offers true random numbers to anyone on the Internet. The randomness comes from atmospheric noise, which for many purposes is better than the pseudo-random number algorithms typically used in computer programs. People use RANDOM.ORG for holding drawings, lotteries and sweepstakes, to drive online games, for scientific applications and for art and music. The service has existed since 1998 and was built by Dr Mads Haahr of the School of Computer Science and Statistics at Trinity College, Dublin in Ireland. Today,...

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Blockchain, one of the Internet's most widely used Bitcoin wallets, has rushed out an update for its Android app after discovering critical cryptographic and programming flaws that can cause users to send digital coins to the wrong people with no warning.

The vulnerabilities affect a subset of people who run Blockchain for Android on versions 4.1 or older of the mobile OS, according to an advisory published Thursday. The most serious of the flaws is the use of the unencrypted HTTP connections when the app's cryptographic engine contacts random.org to obtain random numbers used to generate private keys for Bitcoin addresses. Since January, random.org has required the use of the more secure HTTPS protocol and has returned a 301 Moved Permanently response when accessed through HTTP. As a result, vulnerable installations of Blockchain for Android generated the private key corresponding to the address 1Bn9ReEocMG1WEW1qYjuDrdFzEFFDCq43F, regardless of the address specified by the...

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The blockchain is the new hot technology. If you haven’t heard about it, you probably know Bitcoin. Well, the blockchain is the underlying technology that powers Bitcoin. Experts say the blockchain will cause a revolution similar to what Internet provoked. But what is it really, and how can it be used to build apps today? This post is the first in a series of three, explaining the blockchain phenomenon to web developers. We’ll discuss the theory, show actual code, and share our learnings, based on a real world project.

To begin, let’s try to understand what blockchains really are.

What Is A Blockchain, Take One

Although the blockchain was created to support Bitcoin, the blockchain concept can be defined regardless of the Bitcoin ecosystem. The literature usually defines a blockchain as follows:

A blockchain is a ledger of facts, replicated across several computers assembled in a peer-to-peer network. Facts can be anything from monetary transactions to...

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If you use Blockchain.com for your wallet | Localbitcoins


It got hacked yesterday and some people had their bitcoins stolen. Read here for more details http://www.844bankbtc.com/blockchain-com-wallets-hacked-make-right/


I might get one of those soon. I like the idea.


0.3 btc inc p&p,coin held in escrow till delivery (3 left)


Do Trezors work on chromebooks?


I have been warning people about blockchain.info for years.


be careful if your paper wallet contains the private keys to your coins otherwise stored online they can still be stolen ONLINE. Make sure you get new private keys for paper wallet.


What OS cincinnatistuff,I think they pretty much work on anything,they work indepentently of the computer,but you have to download software for your OS. .


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A blockchain is a distributed database managed by a peer-to-peer network. The distributed database is also called a ledger which is a continuously growing chain of blocks. Each block contains a number of records and each block is linked to a previous block.

It is extremely difficult to change a record in any given block without the alteration of all subsequent blocks and the collusion of the network.

The first implementation of a blockchain was Bitcoin in 2009 invented by an unknown programmer, or a group of programmers, under the name Satoshi Nakamoto.

After the Bitcoin success many blockchain implementations followed such as Litecoin and Peercoin.

Other blockchain implementations introduces new kind of functionalities such as Ethereum and...

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I stumbled upon Christopher Ellis’ “World Citizenship” Blockchain ID concept and was immediately intrigued. His idea is to create proof of an individual’s existence by storing their PGP identity in the blockchain.

The trick is that the blockchain acts as an immutable database that includes full history tracking, meaning that a record can be proven to exist in some state at some time. These services are similar to this concept:

This post will detail how to create a Blockchain Identity.

To begin, you will need:

GPG key with signing abilities Bitcoin wallet with a small balance Keybase.io account

Keybase.io is currently alpha, and you need an invite to get an account, but you can probably snag an invite from Reddit (that’s where I got mine).

I will be using Debian Linux for this tutorial. I recommend the following packages:

gpg : For signing files electrum : For managing bitcoins ruby : For running the scripts below

First you need to create a...

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A widely used Bitcoin wallet service plans to issue refunds to people who saw their bitcoins stolen as a result of a weakness in its application.

Blockchain.info, which has a Web-based service called My Wallet, has also upgraded its application after finding a vulnerability similar to one discovered earlier this month in some Bitcoin wallet programs running on the Android mobile OS.

“Likely if you have been affected by this problem your coins will have been taken already,” a Blockchain.info official wrote on the Bitcointalk.org forum. “All affected users will be refunded in full.”

The number of affected users is small, said Roger Ver, who is an investor in Blockchain.info, via email. Blockchain.info expects to refund around 50 BTC or $5000, he said.

Interest in Bitcoin has surged since its debut just four years ago. The system offers a low-cost way to transmit virtual currency over the Internet, and many companies and entrepreneurs are working to...

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Antony Lewis is a bitcoin and blockchain consultant and blogger, who previously served as the director of business development at bitcoin exchange itBit.

In this article, Lewis attempts to break down some of the more misunderstood questions circulating among institutions seeking to adapt distributed blockchain tech for alternative uses.

There are good reasons and bad reasons to use blockchains.

In conversations with people considering blockchain use cases, I have noticed common confusions arising from certain words. At issue, is that they were initially used in a narrow context (usually to describe bitcoin's blockchain), and are now being interpreted more generically for other blockchains, in cases where they may no longer apply.

In this post, I hope to untangle some of these common misconceptions.

Theme: Blockchains are secure

Writing data

Bitcoin has specific security features for writing data due to the burden of...

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CoinDesk spoke to Nicolas and Ben of Blockchain.info about it being the #1 bitcoin site, how it will remain so into the future, why its users trust it so much and how online wallets need to be easy to use as well as secure.

The Blockchain.info team has been busy. The site grew by over 50% last month, with over 118 million page views and over 3 million unique visitors in November 2013. The number of registered bitcoin wallets jumped from 500,000 at the start of the month to 800,000 at the end and is now on its way to 1 million. These 'My Wallet' users engage in about 24,000 transactions daily, sending about 150,000 BTC in total.

That's quite a change from January 2013, when the site boasted "over 110,000 users." Even in August, daily transactions were around 100,000 BTC (worth $12m at the time). Due to the way Blockchain's encryption works, it is impossible to know the total number of bitcoins stored there.


Blockchain.info has grown to be not...

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