Nethereum.Siwe.Core

NuGet: Nethereum.Siwe.Core | Source: src/Nethereum.Siwe.Core/

Nethereum.Siwe.Core

Core models and utilities for Sign-In with Ethereum (EIP-4361). This package provides the SiweMessage model, message parsing, string building, and validation helpers used by both Nethereum.Siwe and downstream authentication providers.

Key Components

Class	Purpose
SiweMessage	EIP-4361 message model with Domain, Address, Statement, URI, Nonce, expiration, and chain binding
SiweMessageParser	Parses a plain-text SIWE string back into a SiweMessage (regex and ABNF modes)
SiweMessageStringBuilder	Builds the canonical plain-text representation for signing
DefaultSiweMessage	Pre-configured SiweMessage subclass with sensible defaults

Usage

Build a SIWE message string

var message = new SiweMessage
{
    Domain = "example.com",
    Address = "0xAb5801a7D398351b8bE11C439e05C5B3259aeC9B",
    Statement = "Sign in to Example",
    Uri = "https://example.com",
    Version = "1",
    ChainId = "1"
};
message.SetIssuedAtNow();
message.SetExpirationTime(DateTime.UtcNow.AddMinutes(10));
message.SetNotBefore(DateTime.UtcNow);
message.Nonce = "randomnonce123";

string plainText = SiweMessageStringBuilder.BuildMessage(message);

Parse a SIWE message

var parsed = SiweMessageParser.Parse(plainText);
// parsed.Address, parsed.Domain, parsed.Nonce, etc.

Validate timing

bool valid = message.HasMessageDateStartedAndNotExpired();
bool hasRequired = message.HasRequiredFields();

Relationship to Other Packages

• Nethereum.Siwe — Adds session/nonce management, signature verification, and user registration checks on top of these core models
• Nethereum.UI — NethereumSiweAuthenticatorService orchestrates SIWE authentication in Blazor Server using this package