Understanding Ethereum’s Data Structure: A Simple Guide
Tags: merklepatriciatries, ethereum, blockchain, merkle
Published: 2023-11-29 13:33:09

Have you ever wondered what Merkle Patricia Trie was? I know you've also thought about it at some point. I found a way to simplify it for you, breaking it down to what I call "its simplest form."
I'm really happy to share this because I know it will help a whole lot.
Now, let's dive into this amazing article on Merkle Patricia Tries.

Note: Try to picture this whole scenario.



![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/49pjwdv7h1oovf7yd4m9.jpg)

Consider Ethereum as a massive digital notebook where all transactions are recorded. This notebook is not governed by a single entity, as it is decentralized. Now, each page in this notebook is a “block,” and it has a list of transactions. When a page is filled, we seal it with a special code called a “hash.” This hash is like a unique fingerprint for that page, and it also contains the fingerprint of the previous page. So, all the pages are connected in a chain, and if you try to change something on an old page, it messes up the fingerprints, and everyone can see it. This makes it really hard to cheat or tamper with the transactions.
Ethereum uses a special system called the “Merkle Patricia Trie.” Pronounced “try,” it’s basically a structured way of arranging and protecting all the important details.

How does this work? We will see that in a bit.

## The Family Tree Analogy


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/j3m3gbc1oevgi6tkyvs1.jpg)

Think of the Merkle Patricia Trie as a tree—a family tree. At the top of this tree is the main root, like the last name of a big family. This root represents all the information stored in Ethereum. Each branch of the tree leads to more branches or leaves, much like the different branches of a family tree leading to various relatives.

But Ethereum’s tree deals with information, not names and relationships. In this family tree, any item of data—transaction or account balance, for example—is comparable to one individual. Every piece of data has a unique identity, just as every individual has distinctive qualities.

To make things even more efficient, Ethereum uses a special type of code called hexadecimal. It’s like a mix of numbers and letters that helps organize and quickly find information within this tree-like structure. This code acts as the address of a particular piece of information.

Now, to keep everything secure, each piece of information in this tree has a unique code called a “hash.” This hash acts as a fingerprint—no two pieces of information have the same fingerprint. If anything changes in the information, even a tiny bit, its fingerprint (hash) changes too. This way, Ethereum can easily spot if anything has been tampered with or updated.
One cool thing about this tree structure is that it’s super smart about updates. Let’s say something changes—maybe a new transaction happens or an account balance is updated. Instead of reorganizing the entire tree, the system only updates the specific part related to that change. This keeps things speedy and efficient.

Basically, the main hash at the top of the tree acts like a seal on a precious box. If anything within that box changes, even slightly, the seal changes too. This alerts the system that something has been modified or added, ensuring the integrity and security of all the information stored in Ethereum.

I’m sure you made that big family picture, and you can see it right now. So, let’s introduce three essential branches in this family information tree: the “World State,” the “Transaction,” and the “Transaction Receipt.”

**World state:** This is like a family album capturing the current financial state of everyone in Ethereum. Think of it as a snapshot of all account balances and contract storage.

**Transaction:** This is similar to a diary entry, documenting the who, what, and when of a transaction. This contains details of a particular action, like sending cryptocurrency from one account to another, smart contract execution, decentralized application (DApp) interactions, and token swaps on decentralized exchanges. Each Ethereum transaction consists of several components. A few are Nonce, Gas Price, Gas Limit, to (recipient), value, data, V, R, S (Digital signature), etc.

**Transaction Receipt:** The “Transaction Receipt” is like a confirmation slip for a transaction. It verifies that a transaction has been successfully completed, detailing any changes in the world. Transaction receipts consist of post-transaction state, total gas used, logs created through execution of the transaction, etc.

It is necessary to comprehend Ethereum’s data structure in order to navigate the blockchain ecosystem. It influences everything, from transactions to smart contracts, and serves as the foundation for information organization and security. This information is essential for effectively interacting with Ethereum, guaranteeing informed choices and the integrity of interactions in this decentralized environment, regardless of whether you’re a developer, user, or enthusiast.

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