Markdown Memoirs

Unlocking Ethereum’s Potential: A Deep Dive into EIP-712

June 30, 2025
By Aditya Mishra
Ethereum Web3 EVM EIP Smart Contracts Digital Signatures NFTs

Introduction

While auditing, I discovered the crucial role of Ethereum Improvement Proposal 712 (EIP-712), a standard that has revolutionized Ethereum’s approach to digital signatures and data handling. Much like EIP-155 changed transaction structure to prevent replay attacks, EIP-712 introduced structured, typed data for improved security and transparency. This enhancement transformed user interactions, providing clarity in Ethereum transactions and offering crucial protections against certain classes of security threats, a significant advancement in blockchain development.

What is EIP-712?

EIP-712, short for Ethereum Improvement Proposal 712, introduced a standardized way for Ethereum-based applications to handle digital signatures by employing typed, structured data. This standard defines how contracts can request users’ permissions or authorizations with clear, readable data, enhancing the security and usability of Ethereum transactions.

Key Components of EIP-712

Typed Data

EIP-712 uses typed data — a structured format with predefined types and fields. This shift provides users with a clear format for understanding messages or authorization requests, eliminating the confusion often associated with cryptic transaction data.

Domain Separator

The domain separator is a cryptographic nonce that helps prevent replay attacks by ensuring each message remains unique to its context. It incorporates essential parameters like the contract’s address, chain ID, and other relevant identifiers to make each request distinct.

Message Structure

The EIP-712 standard defines a specific message structure, including field names, types, and values. This structure allows users to verify a message’s authenticity and purpose easily, adding an extra layer of trust to Ethereum transactions.

Why is EIP-712 Significant?

EIP-712 offers several notable benefits that strengthen the Ethereum ecosystem:

1. Improved User Experience

By introducing typed data and structured messages, EIP-712 enhances user experience, allowing users to verify transaction details more intuitively. This improvement reduces the likelihood of errors or misinterpretations, empowering users to approve transactions with greater confidence.

2. Enhanced Security

EIP-712 also reduces risks associated with phishing attacks and malicious contract interactions. By standardizing the message format and including a domain separator, EIP-712 makes it significantly more challenging for attackers to deceive users into approving unauthorized actions.

3. Interoperability

Designed to work seamlessly with existing Ethereum wallets and clients, EIP-712 is easily integrated into applications, encouraging wide adoption across the Ethereum ecosystem. This interoperability benefits both developers and users, promoting a more cohesive experience across different platforms.

Problem-Solving: Before and After EIP-712

Before EIP-712, users had to sign raw hexadecimal strings, a process as bewildering as reading a foreign contract without a translation. This confusion opened the door to mistakes and even malicious exploitation. With EIP-712, however, data signing is now contextualized and structured. It feels more like a translator turning an unfamiliar document into clear, understandable terms, empowering users to sign with confidence.

How Does EIP-712 Work?

Implementing EIP-712 in an Ethereum-based application involves a few essential steps that allow developers to securely request user authorizations:

Define the Message Structure

Developers outline the message’s structure by specifying field types, names, and values in typed data. This step provides a clear, unambiguous request format for the user.

Generate the Domain Separator

The domain separator is generated with parameters like the contract’s address and chain ID, making each message uniquely tied to its originating context.

Hash the Message

Using the keccak256 cryptographic hash function, developers hash the structured message and domain separator to produce a unique message hash.

Obtain User Authorization

The structured message is presented to the user for approval. The user can review and authorize the transaction, understanding its full context and details.

Verify the Signature

After the user authorizes the transaction, developers verify the signature with the message hash and the user’s public key to confirm authenticity.

Lazy Minting: Another Use Case of EIP-712

A fascinating application of EIP-712 is in lazy minting, a feature that is particularly useful for NFT creators aiming to minimize upfront gas fees. Here’s how it works from the perspective of an NFT creator.

Imagine I’m an artist, and I’ve created an original NFT artwork — let’s say a toucan with two cans of beans around its neck. It’s unique, a potential rival to the Bored Ape NFTs! But there’s one catch: I only want to pay minting fees if my artwork actually sells. Paying gas fees for an unsold NFT can be costly, so I opt for lazy minting.

The Lazy Minting Process

Here’s a step-by-step guide to how lazy minting works:

  1. Define NFT Details: I fill out the necessary details of my NFT, like its name, attributes, and any unique characteristics.
  2. Sign with EIP-712: Instead of immediately minting the NFT on-chain, I sign its metadata using the EIP-712 standard. This standard allows me to sign the data off-chain without incurring gas costs at this stage.
  3. Store Signature and Metadata: The NFT marketplace stores my signed metadata and signature in its database of available NFTs, making the toucan artwork available for sale without incurring any minting fees.
  4. Buyer Comes Along: When a buyer, let’s call him Sam, decides to purchase the NFT, he clicks the “Buy” button.
  5. Fetch Metadata and Signature: The marketplace retrieves the NFT’s metadata and signature from its database, ready to complete the transaction.
  6. Verify Creator and Mint NFT: Using the metadata and signature, the marketplace verifies my address as the original signer and creator. If the verification is successful, the NFT is minted on-chain. If the signer doesn’t match the creator, it means the metadata may have been tampered with, invalidating the NFT.
  7. Transfer Ownership and Funds: Sam receives the NFT, and I receive the payment minus the gas fees for minting and any marketplace fees.

Lazy minting is just one of many innovative uses of EIP-712, providing a practical, cost-effective solution for creators to list NFTs without upfront costs, paying only if a sale occurs. This flexibility is reshaping how NFT marketplaces operate, making them more accessible and creator-friendly.

Conclusion

Ethereum Improvement Proposal 712 (EIP-712) represents a significant step forward in handling digital signatures within Ethereum-based applications. By leveraging typed data and structured messages, EIP-712 enhances usability, strengthens security, and improves interoperability across the Ethereum ecosystem. As more developers adopt EIP-712, we can anticipate even greater advancements in the security and user-friendliness of Ethereum applications, making blockchain technology more accessible and reliable for users everywhere.