A Revolutionary Approach To Academic Validation Usingethereum
A Revolutionary Approach to Academic Validation UsingEthereum CryptoCreditor is a HackRice 2017 project by Kunal Shah, Jack Duryea, Shashank Mahesh, and Yorke Rhodes IV. It provides a fast and secure degree verification solution via blockchain technology. Check out the source code on our github . Students at Rice and at universities across the country are currently in the process of applying to internships and full-time positions. A critical step of the employment application process is convincing employers of the validity of academic credentials. Existing solutions for verifying the integrity of academic degrees are slow, expensive, and inefficient. The problem lies in how academic records across the country are stored and retrieved. Universities rarely distribute or verify transcripts themselves. Rather, they outsource this responsibility to The National Clearinghouse . This relieves universities of the costs of managing records on a case-by-case basis, but creates a central authority responsible for answering all academic verification queries. The resulting system necessitates redundant transactions by the middleman and creates an inefficient medium between students, employers, and universities. Weve built a decentralized application on top of the Ethereum network to allow the secure and instantaneous validation of academic credentials. Our solution uses the blockchain as a ledger of academic credentials. The underlying technology is a distributed peer-to-peer record-keeping solution that builds a system of trust around academic credentials. There are two portals: a university portal and a student portal. Through the university portal, users are required to authenticate themselves as accredited universities. Once authenticated, they are granted access to edit the cr Continue reading >>
Poa Network: Public Ethereum Sidechain With Proof Of Authority Consensus By Independent Validators.
Building a service on top of a public blockchain has both high technical barriers of entry and significant upfront costs. As the result, many small and medium businesses are excluded from adopting and enjoying the benefits of the blockchain technology. We are building a public network that combines speed, security, and cost efficiency, previously only available to private networks. We aspire to become a decentralized hub for open networks based on PoA consensus. We see POA Network as a first step towards realizing our vision of horizontal blockchains scalability by creating a swarm of blockchains with Proof of Authority consensus, connected by interledger protocols. POA Network is designed as a general application blockchain. I.e. what can be done on Ethereum network, can also be done on POA Network. Organizations can build their own networks with their own validators based on POA Network's ceremony and governance. Developers can deploy DApps using our PoA framework. We envision the most immediate use cases in identity (obviously, because its a part of our consensus), crowdfunding, real estate transactions and many more. But the most innovative use cases are probably the ones we have not yet thought about. Proof of Authority (PoA) is an alternative consensus mechanism, which does not depend on the nodes solving arbitrarily difficult mathematical problems, but instead uses a set of "authorities" - nodes that are explicitly allowed to create new blocks and secure the blockchain. Validators on POA Network are the known people who validate the blocks. Proof of Authority means that they stake their identity to secure the network. Their identity is subject to a number of verification requirements, including proof of address and no criminal record. The Master of Ceremony is t Continue reading >>
How To Find $10m Just By Reading The Blockchain
How to Find $10M Just by Reading the Blockchain Two weeks ago, one Golem enthusiast and GNT holder reported a strange GNT transfer transaction bug. After investigating the data attached to the transaction, I discovered that there had to be a problem in the way the exchange was preparing data for the transaction. Oh no, I thought, this bug could be used to empty the whole GNT account on the exchange! And quite a large number of tokens were stored there! The bug was indeed the exchanges fault, but it was also related to the way Ethereum contracts see the transaction input data and Solidity ABI (e.g. the way the methods of Solidity contracts encode and decode arguments). So of course it was not specific to GNT, but indeed to all ERC20 tokens, as well as other contracts which have transfer-like methods. Yes you read it right: this could potentially work for any Ethereum-based token listed on said exchange, if only withdrawals were managed in the same way as GNT. We do not know this to be the case, but assume it was very likely. Raw Ethereum contracts have neither methods nor functions. Methods are features of high level languages like Solidity, and they use the Ethereum Contract ABI to specify how a contracts bytecode is divided into methods, as well as how different types of arguments are encoded in transaction input data. (See for a reference.) To invoke the transfer(address a, uint v) method of the GNT contract to transfer 1 GNT to address 0xabcabcabcabcabcabcabcabcabcabcabcabcabca one needs to include 3 pieces of data: 32 bytes, with the destination address (20 bytes) filled with leading zeros: 000000000000000000000000abcabcabcabcabcabcabcabcabcabcabcabcabca 32 bytes, being the value to transfer, 1 * 10 GNT: 0000000000000000000000000000000000000000000000000de0b6b3a7640 Continue reading >>
The Erc20 Short Address Attack Explained
GOLEM's tech team published a nice find today -- a vulnerability for any service that takes user-generated withdrawal addresses and passes them in unaudited to a transfer function. From their post at : The service preparing the data for token transfers assumed that users will input 20-byte long addresses, but the length of the addresses was not actually checked. edit: I mistook bytes and nibbles, thanks to Noel Marsk for the careful reading! The server taking in user data allowed an Ethereum address that was less than 20 bytes: usually an Ethereum address looks like 0x1234567890123456789012345678901234567800. What if you leave off those trailing two zeros (one hex byte equal to 0)? The Ethereum VM will supply it, but at the end of the packaged function arguments, and that's a very bad place to add extra zeros. The transfer function arguments get shifted over one byte from the point that a short argument was given, and this shifts over the number of tokens transferred. Let's say I have 1,000 tokens and would like 256,000 -- what do I do? Generate an Ethereum address with a trailing 0. Ethereum addresses are generated pretty much randomly, so on average this will take 256 tries -- almost no time at all. Find an exchange wallet with 256,000 tokens. Send 1,000 tokens to this exchange wallet, crediting my account internally (off chain) with 1,000. Request a withdrawal of 1,000 tokens using my generated address. Critically I will leave off my last "0" byte. What happens then? Read the Golem blog for a clear explanation, but in brief, if the server does not validate the address, it will "pack" everything together and move the amount, the final argument, over one byte, yielding a 67 byte argument to the transfer function when 68 is what's needed. All these arguments are passed Continue reading >>
An Introduction To Ethereum And Smart Contracts: An Authentication Solution
An Introduction to Ethereum and Smart Contracts: an Authentication Solution Bitcoin took the world by suprise in the year 2009 and popularized the idea of decentralized secure monetary transactions. The concepts behind it, however, can be extended to much more than just digital currencies. Ethereum attempts to do that, marrying the power of decentralized transactions with a Turing-complete contract system. In this post we teamed up with Ivo Zieliski, Konrad Kozio, David Belinchon, and Nicols Gonzlez from GFT's Innovation Team to develop a practical application of an Ethereum-based login system for Ethereum users. This system will allow any Ethereum user to prove ownership of an Ethereum account without using his or her private-key each time such proof is required, which is ideal for login systems. Think of "Login with Facebook" for Ethereum users. Read on! This is the third post from a three-post series about Ethereum. Read part 1 and part 2 if you haven't done so. In our previous post we took a closer look at Ethereum, a decentralized, Turing-complete platform for developing applications using a blockchain. In Ethereum, applications run on each node in the network. The results of those computations are then encoded in blocks, which, through the proof-of-work system, are validated by each node in the network. Furthermore, these operations (transactions) are carried on out on behalf of users. Users must sign each transaction with their private-key, thus making it possible to track whether a certain user can perform certain operations or not. In particular, transactions have a cost, and users must be able to pay that cost by spending Ethereum's cryptocoin: Ether. In our previous post we also had a look at practical applications of Ethereum. The Decentralized Autonomous O Continue reading >>
An Introduction To Ethereum And Smart Contracts: A Programmable Blockchain
An Introduction to Ethereum and Smart Contracts: a Programmable Blockchain Bitcoin took the world by surprise in the year 2009 and popularized the idea of decentralized secure monetary transactions. The concepts behind it, however, can be extended to much more than just digital currencies. Ethereum attempts to do that, marrying the power of decentralized transactions with a Turing-complete contract system. In this post we will take a closer look at how Ethereum works and what makes it different from Bitcoin and other blockchains. Read on! In our previous post , we took a closer look at what blockchains are and how they help in making distributed, verifiable transactions a possibility. Our main example was Bitcoin: the world's most popular cryptocurrency. Millions of dollars, in the form of bitcoins, are traded each day, making Bitcoin one of the most prominent examples of the viability of the blockchain concept. Have you ever found yourself asking this question: "what would happen if the provider of this service or application disappeared?" If you have, then learning about Ethereum can make a big difference for you. Ethereum is a platform to run decentralized applications: applications that do not rely on any central server. In this post we will explore how Ethereum works and build a simple PoC application related to authentication. A blockchain is a distributed, verifiable datastore. It works by marrying public-key cryptography with the nobel concept of the proof-of-work. Each transaction in the blockchain is signed by the rightful owner of the resource being traded in the transaction. When new coins (resources) are created they are assigned to an owner. This owner, in turn, can prepare new transactions that send those coins to others by simply embedding the new owner Continue reading >>
Ethereum Address Validation Php
How Can We Do Ethereum Address Validation?
Answered Mar 13, 2018 Author has 308 answers and 106.1k answer views Ever wondered why your Ethereum Address has both upper case and lower case letters. This case-sensitivity of Ethereum Addresses is used for checksum validation. In simpler terms, checksum validation is a way to tell if an address is valid and prevent typos while entering an address. In this article, we shall look into the details of how Ethereum addresses are checksummed. At the end of the article, we shall provide a tool that validates an address using the checksum. Why Checksum is necessary for Ethereum Addresses: Ethereum addresses are 160-bit hexadecimal addresses. Since each address is 40 characters long, a simple typo might transfer Ether to a different address than intended. In such cases, it is impossible to recover ethers or tokens from mistyped address. Therefore Vitalik Buterin, the founder of Ethereum, proposed and implemented some formatting rules for addresses via EIP 55(short form for Ethereum Improvement Protocol). EIP-55 specifies mixed case checksum encoding for addresses to validate an address. At the time of writing this article, some wallets still do not support this validation mechanism. Therefore we provide a tool in this article that validates your address easily. Convert the rest of the address to lower-case. Hash the lowercase hexadecimal string from Step-2 using Keccak 256 algorithm. Compare the obtained hash with the original hex address: Change the nth letter of hexadecimal address to uppercase if the nth bit of the obtained hash is greater than 7. Otherwise, the nth letter of the hexadecimal address should be lowercased. If the address obtained from Step 5 matches with original, then the address is checksummed. If not, the address might have typos such as extra spacing at Continue reading >>
How To Set Up An Erc-20 Compatible Wallet
Using blockchain to create a more equitable media ecosystem, where creators and valuable contributors have a personal stake in the network they build with us. How to Set up an ERC-20 Compatible Wallet PROPS is one of the first consumer-facing crypto projects in the market. We understand that many of those who participated in the PROPS token sales are new to crypto, and thus new to the concept of a wallet. In order to receive PROPS, everyone who participated in our SAFT, CoinList, or Republic Crypto sales will need to set up an ERC-20 compatible wallet. Any ERC-20 wallet can send, receive and hold PROPS. We advise you choose from among the following four options based on their reputation and security: On your Chrome browser: MetaMask [ step-by-step guide ] On your computers hard drive: MyEtherWallet [ step-by-step-guide ] On your mobile device: imToken [ iTunes Store ; Google Play Store ] On an external hardware wallet: Ledger / other Hardware Wallet [ purchase Ledger here ] Please note that hardware wallets are in strong demand, so it may take weeks to ship. Note: wallets from an exchange such as Coinbase do NOT have the ability to receive or hold tokens such as PROPS. Once your wallet is set up, we suggest testing it two different ways: Plugging your wallet address into this validator on this website: . Send a small amount of Ether (0.0001 ETH) from another wallet or exchange, if you have one, to your new wallet. Please look for emails from [email protected] in the upcoming weeks for more specific details and feel free to email us with any questions. Tune into our Telegram group to join the real-time conversation. Thank you again for your ongoing support. Continue reading >>
How Does Ethereum Work,anyway?
Odds are youve heard about the Ethereum blockchain, whether or not you know what it is. Its been in the news a lot lately, including the cover of some major magazines, but reading those articles can be like gibberish if you dont have a foundation for what exactly Ethereum is. So what is it? In essence, a public database that keeps a permanent record of digital transactions. Importantly, this database doesnt require any central authority to maintain and secure it. Instead it operates as a trustless transactional system a framework in which individuals can make peer-to-peer transactions without needing to trust a third party OR one another. Still confused? Thats where this post comes in. My aim is to explain how Ethereum functions at a technical level, without complex math or scary-looking formulas. Even if youre not a programmer, I hope youll walk away with at least better grasp of the tech. If some parts are too technical and difficult to grok, thats totally fine! Theres really no need to understand every little detail. I recommend just focusing on understanding things at a broad level. Many of the topics covered in this post are a breakdown of the concepts discussed in the yellow paper. Ive added my own explanations and diagrams to make understanding Ethereum easier. Those brave enough to take on the technical challenge can also read the Ethereum yellow paper. A blockchain is a cryptographically secure transactional singleton machine with shared-state.  Thats a mouthful, isnt it? Lets break it down. Cryptographically secure means that the creation of digital currency is secured by complex mathematical algorithms that are obscenely hard to break. Think of a firewall of sorts. They make it nearly impossible to cheat the system (e.g. create fake transactions, erase tr Continue reading >>
How Ethereum's Casper Protocol Will Address Problems With Proof Of Stake
How Ethereum's Casper Protocol Will Address Problems With Proof Of Stake Bitcoin and Ethereum both currently operate under a Proof of Work protocol. Ethereum is moving from Proof of Work towards Proof of Stake under its new Casper protocol. Despite its many benefits, the drawbacks of Proof of Stake have prevented its widespread adoption. Casper aims to solve Proof of Stake's drawbacks, resulting in an improvement over existing Proof of Work and Proof of Stake protocols. The updated protocol improves the long term outlook of Ethereum's valuation. An overarching problem that cryptocurrencies must address is called the Byzantine General's Problem . The Byzantine General's Problem essentially simplifies down to: How do you prevent data from being corrupted or falsified in a network where there are nodes that have economic incentive to lie about the data? In application to cryptocurrency, the problem boils down to preventing attackers from lying about a coin's ledger, given the economic incentive of doing so. We need a way to form consensus on the ledger because anyone can create a block, while we only want a unique chain, so we want a way to decide which block to trust. The two main schools of thought to solving the Byzantine General's Problem are Proof of Work (PoW) and Proof of Stake (PoS). Explicitly, a "proof of work" is a piece of data which is difficult (costly, time-consuming) to produce but easy for others to verify and which satisfies certain requirements. Producing a proof of work can be a random process with low probability so that a lot of trial and error is required on average before a valid proof of work is generated. Currently Bitcoin, Ethereum, and the vast majority of other cryptocurrencies utilize some form of proof of work. PoW (referring to the protocol Continue reading >>
Ether - How Can I Check If An Ethereum Address Is Valid? - Ethereum Stack Exchange
Blockchain Developer Api For Bitcoin, Ethereum, Testnet, Litecoin And More | Blockcypher
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Ethereum Address Validator: Tool To Validate Eth Addresses?
Ethereum is an open source, unrestricted, blockchain based distributing computer platform that features scripting (smart contract) functionality. The platform provides a decentralized virtual machine known as the EVM (Ethereum virtual machine). This machine has the capability to execute scripts using public nodes spread all over the globe. Ethereum has also provided a cryptocurrency that is referred to as Ether. The currency can be transferred from one account to another and can be used in compensating all participating nodes for the computations they perform. There is an internal transaction mechanism used to determine the pricing referred to as Gas, and its used primarily in spam mitigation. It also assists in allocating resources throughout the network. The Process of Checking an Ethereum Address The Ethereum Address Validator is a tool that is used in validating Ethereum addresses. The validator is designed for use in cases where payers need to verify whether a transaction receiver has correctly communicated his or her address. It was designed to prevent scenarios where a payment is sent to an unrecoverable or mistyped Ethereum address. Benefits of the Ethereum Address Validator It is backward compatible with common hex parsers, especially those that accept mixed case letters. This allows it to be slowly introduced as time goes by. Ethereum Address Validator ensures that characters do not surpass the 40 length limit The address checksum has been encoded in lower and upper case variation of A-F hexadecimal letters that are contained in an address. This means that if the typed address only includes lowercase letters, it will not be possible to establish whether that particular address is valid or not. When this happens, you will need to request the address sender to Continue reading >>
Ethereum Signature Validation App
Import:This article is for educational purposesonly. Dont attempt to incorporate the codes and methods presented here into working applications and dont use keys that are associated with your real Bitcoin/Ethereum wallets. Key pair (Asymmetric encryption) is one of the building blocks of current blockchain solutions and cryptocurrencies, without it, Bitcoin, Ethereum and other blockchains were not possible. The idea behind this tool is quite simple: Encrypting information using one key (public key) and decryption it using another (private key). This short video gives a great introduction to the concept of key pairs as well as an explanation to the mathematical background behind RSA asymmetric encryption Rememebr that both Bitcoin and Ethereum arent using RSA encryption. Instead theyre using ECC (Elliptic Curve). The mathematical background is different for the two, yet the main principle is the same. As seen in the video, asymmetric encryption has been around for quite some time and its by no mean a unique feature of the blockchain. However, both Bitcoin and Ethereum (and probably many other blockchains) utilize it in a slightly different way. Rather than using the public key to encrypt a message, theyre using the private key to sign a message. This signed message has some interesting proprieties, but the one thing what makes it really useful in the blockchain context is that the public key can be used to validate to authenticity of the signer. original_msg = "hello"private_key = "0x010203..."public_key = "0x0f0e0d..."signed_message = sign(original_msg, private_key) = "0xaabbcc..."validate(public_key, original_msg) = True As you can see, the idea wasnt necessarily to hide the information (the original message need to be presented in order to validateauthenticity of the Continue reading >>