Ethereum blockchain data structure

The aim of this post is to provide as much information, as possible, in relation to how Ethereum stores its transactions, contracts, account balances and more. Ethereum is a transaction-based "state" machine; a technology on which all transaction based state machine concepts may be built [1]. The Ethereum blockchain begins life with a genesis state. From the genesis block onward, activities such as transactions, contracts and mining continually change the state of the Ethereum blockchain. In Ethereum, an example of this would be an account balance stored in the state trie changing when a transaction, in relation to that account, takes place. The state is not stored in the blocks of the Ethereum blockchain.

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Content:

• Reading Ethereum Geth database (LEVELDB)
• A gentle introduction to Ethereum
• Getting Deep Into Ethereum: How Data Is Stored In Ethereum?
• Decentralized Storage
• Which Crypto Projects Are Based on Ethereum?
• Build a blockchain analytic solution with AWS Lambda, Amazon Kinesis, and Amazon Athena
• Subscribe to RSS

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Reading Ethereum Geth database (LEVELDB)

This post is a continuation of my Getting Deep Into Series started in an effort to provide a deeper understanding of the internal workings and other cool stuff about Ethereum and blockchain in general which you will not find easily on the web.

Here are the other parts of the Series:. First of all, we have to see that what all things we need to store for making the blockchain system work. As we can see here that we can change the state by executing a transaction on it. Here we have to keep track of the balances and other details of different people states and the details of what happens between them on blockchain transactions.

Different platforms handle this differently. Here we will see how Bitcoin and Ethereum handle this. The transfer of value in bitcoin is actioned through transactions. Firstly, bitcoin UTXOs cannot be partially spent. If a bitcoin user spends 0. Secondly, at the most fundamental level, bitcoin does not maintain user account balances. With bitcoin, a user simply holds the private keys to one or more UTXO at any given point in time. Digital wallets make it seem like the bitcoin blockchain automatically stores and organizes user account balances and so forth.

This is not the case. The UTXO system in bitcoin works well, in part, due to the fact that digital wallets are able to facilitate most of the tasks associated with transactions. Including but not limited to:. One analogy for the transactions in the UTXO model is paper bills banknotes.

Each bill can only be spent once since, once spent, the UTXO is removed from the pool. In contrast to the information above, the Ethereum world state is able to manage account balances, and more. The state of Ethereum is not an abstract concept. As with all other blockchains, the Ethereum blockchain begins life at its own genesis block. From this point genesis state at block 0 onward, activities such as transactions, contracts, and mining will continually change the state of the Ethereum blockchain.

In Ethereum, an example of this would be an account balance stored in the state trie which changes every time a transaction, in relation to that account, takes place. Importantly, data such as account balances are not stored directly in the blocks of the Ethereum blockchain. Only the root node hashes of the transaction trie, state trie and receipts trie are stored directly in the blockchain.

This is illustrated in the diagram below. You will also notice, from the above diagram, that the root node hash of the storage trie where all of the smart contract data is kept actually points to the state trie, which in turn points to the blockchain. We will zoom in and cover all of this in more detail soon. There are two vastly different types of data in Ethereum; permanent data and ephemeral data.

An example of permanent data would be a transaction. Once a transaction has been fully confirmed, it is recorded in the transaction trie; it is never altered.

An example of ephemeral data would be the balance of a particular Ethereum account address. The balance of an account address is stored in the state trie and is altered whenever transactions against that particular account occur. It makes sense that permanent data, like mined transactions, and ephemeral data, like account balances, should be stored separately.

Ethereum uses trie data structures to manage data. The record-keeping for Ethereum is just like that in a bank. The bank tracks how much money each debit card has, and when we need to spend money, the bank checks its record to make sure we have enough balance before approving the transaction.

An incrementing nonce can be implemented to counteract this type of attack. In Ethereum, every account has a public viewable nonce and every time a transaction is made, the nonce is increased by one. This can prevent the same transaction being submitted more than once. Note, this nonce is different from the Ethereum proof of work nonce, which is a random value. Like most things in computer architecture, both models have trade-offs. Some blockchains, notably Hyperledger, adopt UTXO because they can benefit from the innovation derived from the Bitcoin blockchain.

We will look into more technologies that are built on top of these two record-keeping models. The state trie contains a key and value pair for every account which exists on the Ethereum network.

A storage trie is where all of the contract data lives. Each Ethereum account has its own storage trie. Each Ethereum block has its own separate transaction trie. A block contains many transactions. The order of the transactions in a block are of course decided by the miner who assembles the block. The path to a specific transaction in the transaction trie, is via the RLP encoding of the index of where the transaction sits in the block.

Mined blocks are never updated; the position of the transaction in a block is never changed. The main Ethereum clients use two different database software solutions to store their tries. Rocksdb is out of scope for this post. LevelDB is an open source Google key-value storage library which provides, amongst other things, forward and backward iterations over data, ordered mapping from string keys to string values, custom comparison functions and automatic compression. Whilst Snappy does not aim for maximum compression, it aims for very high speeds.

Leveldb is an important storage and retrieval mechanism which manages the state of the Ethereum network. As such, leveldb is a dependency for the most popular Ethereum clients nodes such as go-ethereum, cpp-ethereum and pyethereum. To learn more, we have to access the data in leveldb using the appropriate Patricia trie libraries.

To do this we will need an Ethereum installation. Here is a easy to follow tutorial for setting up your own Ethereum private network. We will provide our code examples and screen captures from our Ethereum private network. As we mentioned previously there are many Merkle Patricia Tries referenced in each block within the Ethereum blockchain:.

To reference a particular Merkle Patricia Trie in a particular block we need to obtain its root hash, as a reference. The following commands allow us to obtain the root hashes of the state, transaction and receipt tries in the genesis block. Note: If you would like the root hashes of the latest block instead of the genesis block , please use the following command.

The following commands will further prepare our environment. From this point, running the following code will print a list of the Ethereum account keys which are stored in the state root of your Ethereum private network.

You will have noticed that querying leveldb returns encoded results. In short, Ethereum have extended on the trie data structures. The following example uses ethereumjs. The ethereumjs repositories are easy to install and use; they will be perfect for us to quickly peer into Ethereum leveldb database. This clever upfront design has many advantages. Given that mobile devices and Internet of Things IoT devices are now ubiquitous, the future of e-commerce depends on safe, robust and fast mobile applications.

As we acknowledge advances in mobility, we also acknowledge that the constant increase in blockchain size is inevitable. It is not practicable to store entire blockchains on everyday mobile devices. Every function put, update and delete performed on a trie in Ethereum utilizes a deterministic cryptographic hash.

This cryptographic feature provides an opportunity for light clients devices which do not store the entire blockchain to quickly and reliably query the blockchain i. An interesting idea, mentioned in the Ethereum white paper is the notion of a savings account. You may recall our discussion about bitcoin UTXOs at the start of this article.

UTXOs are blind to blockchain data, and as we discussed, the bitcoin blockchain does not actually store a users account balance. For this reason the base protocol layer of bitcoin is far less likely or perhaps unable to implement any sort of daily spend limits. As work continues in this space we will see a lot of development in light clients.

More specifically, safe, robust and fast mobile applications, which can interact with blockchain technologies. A successful blockchain implementation in the e-commerce space must bolster speed, safety and usability. It is always possible to improve consumer confidence as well as increase mainstream adoption by providing superior usability, safety and performance through smart design. Thanks to Timothy McCallum for his wonderful explanation on states in Ethereum.

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Interview Decentralized Interview. Call me, text me with Plivo APIs. Originally published by Vaibhav Saini on July 29th 49, reads. We will dive into the data storage layer. This post is a continuation of my Getting Deep into Series started in an effort to provide a deeper understanding of the internal workings of the system. There is a lot of stuff going on This post marks the first in a new… hackernoon. Smart Contract Versioning by vasa.

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A gentle introduction to Ethereum

Are blockchain and distributed ledger technology the same? This is a common misconception that many people have. We are living in a digital age of sound bites and buzzwords. An age where even complex technological solutions are reduced to five words or less. As a result, we are witnessing a rise in cunning businesses attempting to piggyback the so-called crypto boom.

Getting Deep Into Ethereum: How Data Is Stored In Ethereum?

Although Ethereum borrows many ideas that have already been tried and tested for half a decade in older cryptocurrencies like Bitcoin, there are a number of places in which Ethereum diverges from the most common way of handling certain protocol features, and there are also many situations in which Ethereum has been forced to develop completely new economic approaches because it offers functionality that is not offered by other existing systems. The purpose of this document will be to detail all of the finer potentially nonobvious or in some cases controversial decisions that were made in the process of building the Ethereum protocol, as well as showing the risks involved in both our approach and possible alternatives. These principles are all involved in guiding Ethereum development, but they are not absolute; in some cases, desire to reduce development time or not to try too many radical things at once has led us to delay certain changes, even some that are obviously beneficial, to a future release eg. Ethereum 1. This section provides a description of some of the blockchain-level protocol changes made in Ethereum, including how blocks and transactions work, how data is serialized and stored, and the mechanisms behind accounts. Bitcoin, along with many of its derivatives, stores data about users' balances in a structure based on unspent transaction outputs UTXOs : the entire state of the system consists of a set of "unspent outputs" think, "coins" , such that each coin has an owner and a value, and a transaction spends one or more coins and creates one or more new coins, subject to the validity constraints:. A user's "balance" in the system is thus the total value of the set of coins for which the user has a private key capable of producing a valid signature. Ethereum jettisons this scheme in favor of a simpler approach: the state stores a list of accounts where each account has a balance, as well as Ethereum-specific data code and internal storage , and a transaction is valid if the sending account has enough balance to pay for it, in which case the sending account is debited and the receiving account is credited with the value.

Decentralized Storage

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Which Crypto Projects Are Based on Ethereum?

A blockchain is an immutable, append-only distributed database. To work with a blockchain, it is not just about understanding these unique features, but one also needs to understand what data is saved on the blockchain. What does blockchain data look like, i. As the word describes, a blockchain is a chain of blocks, and it works similarly for the existing major chains like Bitcoin, Ethereum, and other Proof-of-Work networks. To simplify, in this article the focus is on the Ethereum blockchain only.

Build a blockchain analytic solution with AWS Lambda, Amazon Kinesis, and Amazon Athena

Ethereum is a decentralized , open-source blockchain with smart contract functionality. Among cryptocurrencies, Ether is second only to Bitcoin in market capitalization. Ethereum was conceived in by programmer Vitalik Buterin. Additionally, many other cryptocurrencies operate as ERC tokens on top of the Ethereum blockchain and have utilized the platform for initial coin offerings. Ethereum has started implementing a series of upgrades called Ethereum 2. Ethereum was initially described in a white paper by Vitalik Buterin , [4] [13] a programmer and co-founder of Bitcoin Magazine , in late with a goal of building decentralized applications. Hoskinson left the project at that time and soon after founded IOHK, a blockchain company responsible for Cardano.

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This article assumes the reader has a basic familiarity with how Bitcoin works. Ethereum is software running on a network of computers that ensures that data and small computer programs called smart contracts are replicated and processed on all the computers on the network, without a central coordinator. The vision is to create an unstoppable censorship-resistant self-sustaining decentralised world computer.

In the medical system, the verification, preservation and synchronization of electronic medical records has always been a difficult problem, and the random dissemination of patient records will bring various risks to patient privacy. In recent years, blockchain has been proposed to be a promising solution to achieve data sharing with security and privacy preservation due to its advantages of immutability. So, a distributed electronic medical records searchable scheme was proposed by leveraging blockchain and smart contract technology. Firstly, we perform a hash calculation on the electronic medical data and store the corresponding value on the blockchain to ensure its integrity and authenticity.

Ethereum is also described as a second-generation blockchain being Bitcoin-like blockchains, the first-generation , supporting the first-time smart contracts and scripting functionality. Smart contracts allow a world of possibilities , and they can pretty much automate anything, being self-executing computer code that lives in a decentralized blockchain. In Ethereum, the smart contracts are written in a programming language called Solidity and these programs are run in the EVM — Ethereum Virtual Machine. You can see the EVM as a giant Turing-complete , decentralized virtual machine distributed across all the Ethereum nodes worldwide. In total, there are around nodes, and pretty much anyone can be a node in the network.

Help us translate the latest version. Page last updated : January 30, This introductory paper was originally published in by Vitalik Buterin, the founder of Ethereum , before the project's launch in