Ethereum: How does a wallet get the public key from an address?

Understanding Ethereum Wallets: Unpacking an Address’s Public Key

As a new cryptocurrency enthusiast or developer, it’s essential to understand how Ethereum wallets store and manage private keys. Despite their simplicity, understanding the inner workings of Ethereum wallets is crucial to creating secure transactions and managing funds on the platform.

In this article, we’ll dive deeper into the process of retrieving an Ethereum address’s public key. It may seem counterintuitive at first, but you’ll be surprised at how this information is actually used to facilitate transactions on the blockchain.

The Address Format

Ethereum addresses consist of three parts:

• Prefix

  : A 4-character string that identifies the network (e.g., “0x”, “0XB9”)

• Group: An alphanumeric string that represents a unique identifier for the wallet or account

• Hash: A 64-character hexadecimal string that serves as a checksum

Public Key Recovery

When you create an Ethereum address, a public key is associated with it. This public key is not the same as the private key used to sign transactions.

The process of recovering an address’s public key involves:

• Address Parsing: The wallet or smart contract takes the address and parses it into its constituent parts.

• Group Extraction: The wallet extracts the group portion of the address, which contains the unique identifier for the account.

• Hash parsing: The wallet parses the hash to determine if it is valid and related to the account owner.

Why is a public key needed?

Although only the public key is used to sign transactions on the blockchain, the wallet still needs to know this information to:

• Securely store private keys: Even if they don’t actually store the private key, wallets need to keep it safe and generate new ones as needed.

• Verify account ownership: Wallets can use the public key to verify that a specific address belongs to a specific account owner.

Example use case

Suppose you have an Ethereum wallet with an address 0x1234567890abcdef. The corresponding private key is securely stored inside the wallet. To retrieve the public key, you must:

• Parse the address into its parts.

• Extract the group part (e.g. “123456”).

• Analyze the hash to verify that it is valid.

With this extracted public key, you can use it to sign transactions on the blockchain and interact with other wallets that support Ethereum.

Conclusion

In conclusion, while addresses are really just public keys encoded and hashed with a prefix, they actually store information about an account or wallet. The process of retrieving a public key from an address involves analyzing the address, extracting the group part, and analyzing the hash to determine its validity. This understanding is essential for creating secure transactions on Ethereum and managing funds effectively.

By understanding this concept, you will be better equipped to navigate the world of Ethereum wallets and make informed decisions when interacting with the platform.