Sign-In with Ethereum

The five-minute read

One action, walked through

1. Open ERC 4361 and read the status line before the examples.
2. Write down the rule in one sentence. A fair version of that sentence is: Sign-In with Ethereum describes how Ethereum accounts authenticate with off-chain services by signing a standard message format parameterized by scope, session details, and security mechanisms (e.g., a nonce).
3. Name the object that changes: MUST, NOT, REQUIRED.
4. Ask what an old client, an old contract, or an offline counterparty does. If the document is silent, the silence is part of the design.

The argument, unpacked

What has to be true

• You are implementing ERC 4361 at the status the text itself states: Final.
• The object that has to change is MUST, NOT, REQUIRED. A neighbouring document with a similar name is not this one.
• Wallet support is not the same as consensus validity.

What happened after the paper

The source marks this final. That is a statement about the text, not a promise that every wallet or node has shipped it. Later documents can narrow, replace, or ignore this one. Cite the number you mean.

What to check before you use the idea

• What is covered by the signed bytes in Sign-In with Ethereum?
• Can the same signature be replayed on another chain, account, or message?
• Which primitive does the text require: MUST, NOT, REQUIRED?

Terms

ERC 4361

The public text titled Sign-In with Ethereum.

Final

The document's own label for how finished the text is. It is not a market fact.

The problem the paper names

A signature that does not commit to what the user saw can be replayed into a different spend, a different chain, or a different message.

What the design proposes

• Sign-In with Ethereum describes how Ethereum accounts authenticate with off-chain services by signing a standard message format parameterized by scope, session details, and security mechanisms (e.g., a nonce).
• The goals of this specification are to provide a self-custodied alternative to centralized identity providers, improve interoperability across off-chain services for Ethereum-based authentication, and provide wallet vendors a consistent machine-readable message format to achieve improved user experiences and consent management.
• When signing in to popular non-blockchain services today, users will typically use identity providers (IdPs) that are centralized entities with ultimate control over users' identifiers, for example, large internet companies and email providers.

How the mechanism is specified

• Taken from the specification, the next constraint is: The goals of this specification are to provide a self-custodied alternative to centralized identity providers, improve interoperability across off-chain services for Ethereum-based authentication, and provide wallet vendors a consistent machine-readable message format to achieve improved user experiences and consent management.
• Locate MUST, NOT, REQUIRED in ERC 4361 and apply it to one transaction or call.
• Then check the failure the class of rule always has: a node that did not upgrade, a reverted call, a replayed signature, or a peer that does not speak the message.

What this page does not treat as proven

• A signature scheme is not a privacy system. It hides the signer only if the protocol says so.
• Wallet support is not the same as consensus validity.
• The source marks this final. That is a statement about the text, not a promise that every wallet or node has shipped it.

Why a venture studio still reads it

Use ERC 4361 when a pitch says 'Sign-In with Ethereum' without saying whether the rule is consensus, policy, or an interface. The number is the citation. The pitch is not.