Author Topic: Qtum - UTXO based POS Smart Contracts | TESTNET LIVE!  (Read 4540 times)

Offline vindyne8

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The Qtum Whitepaper Has Been Updated:

Please visit https://qtum.org/en/white-papers to download.





Account Abstraction Layer Overview

Building on bitcoins reliable and proven-to-deliver blockchain, Qtum stacks its Account Abstraction Layer, allowing the Bitcoin Core 0.13 blockchain to seamlessly interact with the Ethereum Virtual Machine (EVM). With this innovation it is now possible to execute smart contracts and run decentralized applications, simply and securely, in environments that were previously out of reach for Ethereum, combining the endless possibilities provided by smart contracts with the stability and maturity of the bitcoin ecosystem.

Until now, attempts to implement smart contract solutions on top of the bitcoin blockchain have had issues, been lackluster, or failed to break into the mainstream business market. This is primarily due to the fact that the bitcoin blockchain employs an Unspent Transaction Output (UTXO) scheme to associate coins with addresses, rather than the easier to understand, but otherwise problematic, account-based model used by Ethereum.

An account based model works pretty much the way one would imagine:  if Alice has 10 tokens, and sends 5 of them to Bob, who has zero tokens; 5 tokens are simply subtracted from Alice?s balance and added to Bob?s, who now owns 5 coins.  On a UTXO blockchain, however, Alice does not directly hold 10 tokens, but a series of outputs, which are collections of coins resulting from previous transactions.

In such a model, instead of owning 10 tokens, Alice would, for example, hold 3 outputs: (a) consisting of 6 coins, (b) consisting of 2 coins, and (c) consisting of another 2 coins. In this scenario Alice couldn?t simply send 5 coins to Bob, but instead she (or her wallet, for that matter) would have to pick the best-suited output and receive ?change? in return (a process called coin picking). In our example this means that Alice would transfer output (a), consisting of 6 coins, and receive 1 coin back as ?change?. This ?change? is what is called the Unspent Transaction Output, or UTXO. After the transaction Alice would still hold 3 outputs, this time (a) consisting of 1, while (b) and (c) remain 2.

Employing such a seemingly complex bookkeeping scheme allows the Bitcoin blockchain to support Simple Payment Verifications or SPVs. The SPV protocol enables the support of light wallets, which are wallets that can interact with the Bitcoin network in a decentralized and trustless manner, without having to download the entire Bitcoin blockchain. This property is immensely useful for mobile applications or in any low bandwidth/storage environment.

Until now, Ethereum smart contracts couldn't execute in such environments exactly because Ethereum?s account based blockchain does not provide a SPV analog. To solve this, Qtum builds its decentralized application platform on the proven-to-deliver Bitcoin blockchain and introduces the Qtum Account Abstract Layer, which serves as a communication layer between the Bitcoin Core 0.13 protocol and the EVM.

To achieve this, Qtum has extended the Bitcoin 'Script' language, adding 3 ?opcodes? so that it functions as a vehicle to transport code to the EVM, while adding special processing conditions, executing these EVM-using transactions immediately when added to the blockchain - allowing the EVM to operate within a UTXO environment.

In order to relieve Qtum smart contracts from the need to perform coin picking for every transaction, Qtum comes coded with an automated, generic coin picking algorithm which allows contracts to ignore the UTXO mode of operation, while functioning normally, as if deployed in an account-based environment. This method is what enables Qtum to be compatible with pre-existing Ethereum smart contracts, allowing them to be executed on Qtum with little to no change to their code.

For more information about Qtum?s architecture in general, please read this post or review our  Technical Whitepaper.   

https://qtum.org/ethereum-contracts-on-utxo/

https://qtum.org/wp-content/uploads/2017/01/Qtum-technical-white-paper-draft-version.pdf

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Have questions about the Qtum project? See the FAQ section of the website:



https://qtum.org/en/learn-more-about-qtum/general-faq
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Qtum Crowdsale Reminder

Register for one of the following exchanges ASAP if you wish to participate in the crowdsale

The Qtum crowdsale will start at 12 PM GMT, Thursday, March 16th, 2017


- Bizhongchou
- Yunbi
- ICOAGE
- Allcoin
- ICO365
- BTC9





Want to know more details about the crowdsale:

View the website!

Check out Patrick Dai's speech from Edcon in Paris, below:



Qtum in the News






From the Blog

Qtum Announces Support From PwC
Qtum Releases Whitepaper Detailing Mobile Smart Contracts Platform
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Qtum AMA

Qtum will be hosting two AMAs this week before the crowdsale.



On Tuesday 8:00 pm Beijing Time on 8btc, we will be hosting the first AMA this week. Feel free to ask questions about Qtum and the crowdsale. (Keep in mind this will be in Chinese)



For the English-speaking community, there will be another AMA on Slack on Thursday 6:00 pm Beijing Time. For your local time: [click here](http://www.thetimezoneconverter.com/?t=6:00%20pm%20Thursday&tz=Shanghai&) If you haven't signed up for Qtum slack click the image above, otherwise join up at qtumnexus.slack.com.










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Risk Precaution:

Crypto-token crowdsale is high risk by nature, please read carefully the following Participation Agreement and Prospectus.  By participating in the QTUM Crowdsale, you confirm you fully understand and accept the terms and conditions.

- Agreement on QTUM Crowdsale Participation
 - Prospectus of QTUM Crowdsale



Qtum have released an up-to-date version of their code, and where they are at!

Take a look at the code snapshot:


https://github.com/qtumproject/qtum-snapshot/releases/tag/prototype-snapshot

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Just hours remain until the QTUM crowd-sale goes live!



Register for one of the following exchanges ASAP if you wish to participate in the crowdsale
The Qtum crowdsale will start at 12 PM GMT, Thursday, March 16th, 2017

- Bizhongchou - bizhongchou.com
- Yunbi - yunbi.com
- ICOAGE - icoage.com
- Allcoin - allcoin.com
- ICO365 - ico365.com
- BTC9 - btc9.com





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Re: Qtum - UTXO based POS Smart Contracts | Crowdsale LIVE 63% SOLD!
« Reply #21 on: March 16, 2017, 09:46:01 am »
The Qtum crowd-fund is live, & has so far raised 63%!



Visit the website to participate, while supplies last: https://qtum.org/en/crowdsale
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Re: Qtum - UTXO based POS Smart Contracts | Crowdsale LIVE 63% SOLD!
« Reply #22 on: March 17, 2017, 10:07:48 am »
Qtum Raises US$12.2m In First 24 Hours of Crowdsale



What an amazing 24 hours! The Qtum project raised 12 million dollars in the first day, and thanks you all for your support! Only 19% left for sale, if you would like to participate, please see:

https://qtum.org/en/crowdsale
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Re: Qtum - UTXO based POS Smart Contracts | Crowdsale LIVE 91% SOLD!
« Reply #23 on: March 18, 2017, 09:22:53 am »
The Qtum project sold 90% of the available tokens in the first 48 hours: crowdsale




The sale will now be in phase 2 for the next week, or until it sells out the remaining 10%. See below:




Qtum in the very recent news:


Forbes
NewsBTC
FinanceMagnates
LiveBitcoinNews
Coinspeaker
Coindesk
Coinspot (Russian)
BitcoinMagazine
CryptoCoinsRevolution
Forklog (Russian)
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Re: Qtum - UTXO based POS Smart Contracts | Crowdsale LIVE 97% SOLD!
« Reply #24 on: March 20, 2017, 09:57:51 am »
The Qtum project sold nearly 97% of the available tokens in the first few days: qtum.org/en/crowdsale



The sale will now be in phase 2 for the next few days, or until it sells out the remaining 3%. See below:

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Re: Qtum - UTXO based POS Smart Contracts | Crowdsale is sold out
« Reply #25 on: March 21, 2017, 09:36:19 am »
The crowd-sale is completed, it sold out in 117hrs~
 Here is a message from the Qtum team:


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Re: Qtum - UTXO based POS Smart Contracts | Crowdsale is sold out
« Reply #25 on: March 21, 2017, 09:36:19 am »

Offline vindyne8

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Re: Qtum - UTXO based POS Smart Contracts | TESTNET LIVE!
« Reply #26 on: June 27, 2017, 11:02:34 pm »

Instructions on how to compile from source are listed in the Git. Please see the documentation provided:

Code: [Select]
Quickstart

Build on Ubuntu

This is a quick start script for compiling Qtum on  Ubuntu


sudo apt-get install build-essential libtool autotools-dev automake pkg-config libssl-dev libevent-dev bsdmainutils git cmake libboost-all-dev
sudo apt-get install software-properties-common
sudo add-apt-repository ppa:bitcoin/bitcoin
sudo apt-get update
sudo apt-get install libdb4.8-dev libdb4.8++-dev

# If you want to build the Qt GUI:
sudo apt-get install libqt5gui5 libqt5core5a libqt5dbus5 qttools5-dev qttools5-dev-tools libprotobuf-dev protobuf-compiler

git clone https://github.com/qtumproject/qtum
cd qtum
# Update cpp-ethereum submodule
git submodule update --init --recursive

# Note autogen will prompt to install some more dependencies if needed
./autogen.sh
./configure
make -j2


If you would like to receive Test Network tokens, please PM this account with your address and we will get them sent ASAP.  These test tokens will have no value, so you are free to share them with others for testing. We will have a faucet set up shortly, along with a Win64 QT shortly.

Right now the team is preparing for our launch event in Shanghai, so it may be a touch busy on our side for the next day.

Visit the Qtum Website: https://qtum.org/en/
Join the Qtum Slack: https://qtumslack.herokuapp.com/
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Re: Qtum - UTXO based POS Smart Contracts | TESTNET LIVE!
« Reply #27 on: July 01, 2017, 03:08:49 pm »
The Qtum team is live in Moscow at the http://blockchainhack.ru/ hackathon!

Wish the participants good luck as they compete for 8500 Qtum tokens. This is live in Moscow July 1st-2nd












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Re: Qtum - UTXO based POS Smart Contracts | TESTNET LIVE!
« Reply #28 on: July 10, 2017, 09:27:19 pm »
From the blog post: https://qtum.org/en/blog/qtum-tokens-announcement
___
Qtum Tokens Announcement
___
Qtum Tokens Announcement
July 10, 2017
___
At the request of many Qtum community members, a Qtum ERC-20 token will be released today, Monday, July 10th, and given to the partners that participated in the crowdsale.
___
This will enable users to withdraw their tokens off the exchange they used into ETH wallets that support ERC-20 tokens, like imToken and MyEtherWallet. Please test with small amounts first.
___
The Qtum mainnet is still on schedule to be released in September, which is when these tokens will be allowed to be swapped with Qtum.
___
Thank you for your understanding and support of the Qtum project!
___
Qtum Foundation
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Re: Qtum - UTXO based POS Smart Contracts | TESTNET LIVE!
« Reply #29 on: July 18, 2017, 08:55:12 pm »


QTUM: Building a Better Blockchain Governance
https://hackernoon.com/qtum-building-a-better-blockchain-governance-e2188cc34422
___
Moscow's Blockchain Hackathon Reflects Booming Blockchain Industry in Russia
https://bitcoinmagazine.com/articles/moscows-blockchain-hackathon-reflects-booming-blockchain-industry-russia/


___

What is a blockchain fork?
https://medium.com/@Qtum/what-is-a-blockchain-fork-16cef86c0ad8

___

Energo Labs' First Meetup
https://qtum.org/en/blog/energo-labs-first-meetup


___

See the Qtum "Defining the Blockchain Economy" video here:
https://youtu.be/RS_wd_jmJng

___

Dev Update Week of July 7th
https://forum.qtum.org/topic/218/dev-update-week-of-july-7th

___

Test Network wallet is available on GitHub
 https://github.com/qtumproject/qtum
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Re: Qtum - UTXO based POS Smart Contracts | TESTNET LIVE!
« Reply #29 on: July 18, 2017, 08:55:12 pm »