Smart Contracts News Monday, February 12


Smart Contracts News TLDR / Table of Contents

  • Predicting Random Numbers in Ethereum Smart Contracts
    • Ethereum has gained tremendous popularity as a platform for initial coin offerings (ICOs). However, it is used in more than just ERC20 tokens. Roulettes, lotteries, and card games can all be…
    • Ethereum blockchain, gas price, block variables, higher gas price, smart contracts
  • How Smart Contracts Can Improve Revenue Sharing in the 21st Century.
    • Revenue sharing is truly different in each industry, but at its core revenue sharing is sharing profits or losses among different groups or individuals. Although we may not always see it, the…
    • revenue sharing, smart contracts, , ,
  • How Formal Verification Can Ensure Flawless Smart Contracts
    • Bernhard Mueller, Security Engineer at ConsenSys, lays out how to eradicate errors in the Ethereum bytecode. Smart contract security is serious business. Previously, I wrote about detecting common…
    • state, Smart contract security, formal verification, Ethereum Virtual Machine, certain error states
  • Smart Contracts sicherer machen – mit Hyperledger Sawtooth
    • Hyperledger Sawtooth ist jetzt in Version 1.0 verfügbar. Wir haben mit Dan Middleton gesprochen, dem Projektmanager des Blockchain-Framework.
    • Sawtooth und Fabric, Unterschied zwischen Sawtooth, Dan Middleton Sawtooth, Sawtooth Betreuer kümmern, Anwendungen für Sawtooth

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Score: 10111.773984220907
Tweeted At: Sun Feb 11 20:48:10 +0000 2018
Publish Date: 2018-02-01T03:27:43.238000+00:00
Author: Arseny Reutov


Predicting Random Numbers in Ethereum Smart Contracts

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  • We decided to research smart contracts in order to assess the security of PRNGs written in Solidity and to highlight common design antipatterns that lead to vulnerabilities allowing prediction of the future state.Our research was performed in the following steps:3,649 smart contracts were collected from and GitHub.These contracts were…
  • So if an attackers contract calls the victim contract via an internal message, the same PRNG in both contracts will yield the same outcome.Example 1 Won if block number is even// (note: this is a terrible source of randomness, please dont use this with real money)bool won = (block.number %…
  • In these contracts, the blockhash of the current block was deemed known at runtime and was used as a source of entropy.Example 1 deal(address player, uint8 cardNumber) internal returns (uint8) { uint b = block.number; uint timestamp = block.timestamp; return player, cardNumber, timestamp)) % 52);}Example 2 random(uint64 upper) public returns…
  • The random numbers for the two contracts will be the same.Example 1 random number between 0 maxuint256 constant private FACTOR = rand(uint max) constant private returns (uint256 result){ uint256 factor = FACTOR * 100 / max; uint256 lastBlockNumber = block.number – 1; uint256 hashVal = return uint256((uint256(hashVal) / factor)) %…
  • For instance, popular Ethereum client web3 has the API method web3.eth.getStorageAt(), which allows retrieving storage entries at the specified indices.Given this fact, it is trivial to extract the value of the private variable pointer from the contract storage and supply it as an argument to an exploit:function attack(address a, uint8…

[/vc_column_text][vc_column_text el_class=”topfeed-tags”]Tags: Ethereum blockchain, gas price, block variables, higher gas price, smart contracts[/vc_column_text][/vc_column][vc_column width=”1/2″][vc_separator][vc_column_text el_class=”topfeed-tweet”]

[/vc_column_text][vc_column_text el_class=”topfeed-embedly”]Predicting Random Numbers in Ethereum Smart Contracts[/vc_column_text][/vc_column][/vc_row][vc_row el_id=”How-Smart-Contracts-Can-Improve-Revenue-Sharing-in-the-21st-Century-“][vc_column width=”1/2”][vc_separator][vc_column_text]

Score: 123.1410071942446
Tweeted At: Wed Jan 31 05:53:53 +0000 2018
Publish Date: 2018-01-30T22:46:07.826000+00:00
Author: Rhys Boulanger


How Smart Contracts Can Improve Revenue Sharing in the 21st Century.

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  • How Smart Contracts Can Improve Revenue Sharing in the 21stCentury.Revenue sharing is truly different in each industry, but at its core revenue sharing is sharing profits or losses among different groups or individuals.
  • The teams pool their annual revenue and redistribute it from high grossing team to low grossing ones.Small Business: Owners may choose to use incentives programs, like paying their partners a percentage-based bonus for referring new customers.Challenges With Our Current Revenue Sharing ModelWhen it comes to revenue sharing, there has been…
  • For example, when it comes to music streaming services who combine songs from different artists into one package, they face the issue of how much revenue to allocate to each song.Speedrevenue sharing is a process and in come cases, there is an order to which stakeholders receive their portion of…
  • Using smart contracts, we can ensure that all stakeholders receive their correct share of the revenue by embedding specific terms into a smart contract.For example, lets say you invested a certain amount of cryptocurrency for 15% ownership in a venture.
  • By using smart contracts, you can ensure that right when revenue starts to flow in, 15% of it will be transferred to you wallet in real time.As for speed, there is nothing quicker that the real time transaction mentioned above.

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[/vc_column_text][vc_column_text el_class=”topfeed-embedly”]How Smart Contracts Can Improve Revenue Sharing in the 21st Century.[/vc_column_text][/vc_column][/vc_row][vc_row el_id=”How-Formal-Verification-Can-Ensure-Flawless-Smart-Contracts”][vc_column width=”1/2″][vc_separator][vc_column_text]

Score: 11.716345160179126
Tweeted At: Fri Feb 02 06:06:00 +0000 2018
Publish Date: 2018-01-29T05:23:20.610000+00:00
Author: Bernhard Mueller


How Formal Verification Can Ensure Flawless Smart Contracts

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  • Formal verification allows us to prove conclusively that certain error states can never occur.There is a considerable amount of academic research into semantic modeling of the Ethereum Virtual Machine (EVM) and formal verification of smart contracts using various frameworks (links below).
  • In this article, Ill describe an approach based on symbolic execution and the Z3 theorem prover, and demonstrate that this method is capable of detecting subtle bugs, such as those resulting from Solidity memory addressing mechanics.Our specimen of choice is Ownable, a commonly used base contract that defines the owner…
  • Each state consists of a set of concrete and/or symbolic values associated with the contract account (storage, balance,… ) and virtual machine environment (program counter, call data, etc.), as well as a set of path constraints, i.e. the requirements that must be fulfilled to reach that particular state.Mythrils symbolic execution…
  • We can therefore more easily obtain the set of relevant initial states by selecting from all pairs of global state and machine state (, ) where:An error state exists if it is possible to satisfy the logical formula:In plain English, we attempt to prove that it is impossible to reach…
  • / Ownable.solAnalysis completed.Since no counterexample has been found, we can conclude that Ownable is safe with respect to modifications of the owner state variable, with a few caveats:We assume that the Ethereum virtual machine always behaves correctly;The result only applies to the Ownable contract in isolation, not necessarily to contracts…

[/vc_column_text][vc_column_text el_class=”topfeed-tags”]Tags: state, Smart contract security, formal verification, Ethereum Virtual Machine, certain error states[/vc_column_text][/vc_column][vc_column width=”1/2″][vc_separator][vc_column_text el_class=”topfeed-tweet”]

[/vc_column_text][vc_column_text el_class=”topfeed-embedly”]How Formal Verification Can Ensure Flawless Smart Contracts[/vc_column_text][/vc_column][/vc_row][vc_row el_id=”Smart-Contracts-sicherer-machen-mit-Hyperledger-Sawtooth”][vc_column width=”1/2″][vc_separator][vc_column_text]

Score: 0
Tweeted At: Mon Feb 12 13:43:21 +0000 2018
Publish Date: 2018-02-12T14:41:07+00:00
Author: Gabriela Motroc


Smart Contracts sicherer machen – mit Hyperledger Sawtooth

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  • JAXenter: Eine einzigartige Eigenschaft von Hyperledger Sawtooth ist, dass man Smart Contracts in seiner Lieblingssprache programmieren kann.
  • Ihr untersttzt etwa Go, JavaScript und Python, um nur ein paar zu nennen.
  • Ist Go eine gute Sprache, um Smart Contracts zu programmieren oder Blockchains zu erstellen?
  • Natrlich, es gibt in allen Projekten Bugs und wir werden diese auch in Sawtooth finden und beheben, aber der Groteil der Arbeit aus der Community in den letzten Monaten hat darauf abgezielt, die Plattform abzuhrten und zur Reife zu bringen.
  • Unternehmen knnen also ruhigen Gewissens auf dem API aufbauen, da zuknftige Verbesserungen und Fixes rckwrtskompatibel sein werden.

[/vc_column_text][vc_column_text el_class=”topfeed-tags”]Tags: Sawtooth und Fabric, Unterschied zwischen Sawtooth, Dan Middleton Sawtooth, Sawtooth Betreuer kümmern, Anwendungen für Sawtooth[/vc_column_text][/vc_column][vc_column width=”1/2″][vc_separator][vc_column_text el_class=”topfeed-tweet”]

[/vc_column_text][vc_column_text el_class=”topfeed-embedly”]Smart Contracts sicherer machen – mit Hyperledger Sawtooth – JAXenter[/vc_column_text][/vc_column][/vc_row]

Top Smart Contract Courses

Getting Started with Ethereum Solidity Development (6,530 students enrolled)

By Sebastien Arbogast
  • Understand the basic philosophy behind the blockchain and distributed/decentralized applications
  • The basics of how a blockchain generally works, just enough to be able to use it as a development platform
  • Develop a distributed application, from creating a blank project to deploying it in production all the way through writing smart contracts, unit testing them, and creating a user interface for them
  • How to combine the right tools to put together a consistent development environment
  • The fundamentals of the Solidity smart contract language
  • How to use the Truffle build and testing framework
  • How to deploy a decentralized app to various Ethereum instances (testrpc, private chain, test chain, main net)

Learn more.

Ethereum Blockchain Developer: Build Projects Using Solidity (10,937 students enrolled)

By Ravinder Deol
  • Be Proficient In Solidity Programming By Building Projects In This Course.
  • Understand Blockchain Technology At A Theoretical And Practical Level.
  • Be Aware On A Practical Level Of How Smart Contracts Operate.
  • Be Able To Work With The Ethereum’s Major Core Development Tools.
  • Understand The Core Development Functions Of Ethereum.
  • Understand What Decentralisation Is As We’re Working With This Technology.
  • Be Able To Explain The Structure Of A Solidity Clearly Through Practical Examples.
  • Understand How To Use Web3 In Conjunction With The Project We’re Creating.
  • Be Proficient In Advanced Development With Truffle And Ethereum Studio.
  • Complete A Final Assignment Which Consists Of An Ethereum Blockchain Based Curriculum Vitae.

Learn more.

Ethereum : Decentralized Application Design & Development (9,794 students enrolled)

By Rajeev Sakhuja
  • Leverage the Ethereum tools/software such as Wallet, Geth, MetaMask, Remix, TruffleV4, Ganache....
  • Create an ERC20 Compliant token to launch an Initial Coin Offering (ICO)
  • Setup Private Blockchain Network
  • Develop Smart contracts in Solidity using multiple tools such as Web3/Ganache/TruffleV4/Mocha framework
  • Comfortably describe how Ethereum Blockchain works | Ethers, Gas, POW, POS, Nodes ...
  • Describe how the Blockchain technologies work | Distributed Ledgers, Consensus, Mining ....
  • Develop UI/front end for Decentralized Application in HTML/CSS/Javascript using web3 libraries
  • Develop end to end Decentralized Applications (DAPP) on Ethereum platform
  • Setup private Ethereum networks for development & experimentation
  • Identify and use the right design patterns for developing smart contracts
  • Architect, Design & Build real use cases on Ethereum platform

Learn more.

The Complete Ethereum Course: Get .001 Ether In Your Wallet (4,273 students enrolled)

By Ravinder Deol
  • Understand how Ethereum, the emerging cryptocurrency works, and get involved with it practically as well as learning the theoretical side of the cryptocurrency.
  • Realise how becoming an early adopter of Ethereum gives you the best chance to capitalize on its rise, as many would have missed the meteoric rise of Bitcoin.
  • Undertake your first ever Ethereum transaction by receiving .001 Ether from me for completing this course, I will of course walk you through how to setup your wallet.

Learn more.

Compile Your First Ethereum Smart Contract With Solidity (245 students enrolled)

By Will Bunker
  • Compile a basic smart contract
  • Set a private blockchain for testing
  • Deploy smart contract to blockchain
  • Call the functions on smart contract.

Learn more.

Learn Solidity: Programming Language for Smart Contracts (3,153 students enrolled)

By Toshendra Sharma
  • Develop Ethereum Smart Contracts using Solidity
  • Understand the basics & advance features of Solidity & Ethereum Virtual Machine
  • Develop their own decentralized blockchain applications

Learn more.