eip712-signing — Подпись структурированных данных для Ethereum.Net

--- name: eip712-signing description: Sign and verify EIP-712 typed structured data using Nethereum (.NET). Use this skill whenever the user asks about EIP-712, typed data signing, structured data signing, domain separator, SignTypedData, ERC-2612 Permit signatures, or off-chain message signing with typed schemas using C# or .NET. user-invocable: true --- # EIP-712 Typed Data Signing with Nethereum ## Package ``` Nethereum.Signer.EIP712 ``` ## Namespaces ```csharp using System.Numerics; using Nethereum.ABI.EIP712; using Nethereum.ABI.FunctionEncoding.Attributes; using Nethereum.Signer; using Nethereum.Signer.EIP712; using Nethereum.Util; ``` ## Core Concepts EIP-712 signs structured data with a domain separator, producing signatures that wallets can display in human-readable form. Nethereum maps EIP-712 structs to C# classes using attributes. ## Step 1: Define Typed Structs Each EIP-712 struct becomes a C# class with `[Struct]` and `[Parameter]` attributes. ```csharp [Struct("Person")] public class Person { [Parameter("string", "name", 1)] public string Name { get; set; } [Parameter("address", "wallet", 2)] public string Wallet { get; set; } } [Struct("Mail")] public class Mail { [Parameter("tuple", "from", 1, "Person")] public Person From { get; set; } [Parameter("tuple", "to", 2, "Person")] public Person To { get; set; } [Parameter("string", "contents", 3)] public string Contents { get; set; } } ``` Rules: - Use `tuple` as the Solidity type for nested structs, with the struct name as the fourth `[Parameter]` argument. - The `[Struct("Name")]` value must match the EIP-712 type name exactly. - Parameter order numbers (1, 2, 3...) must match the EIP-712 field order. ## Step 2: Create TypedData with Domain ```csharp var typedData = new TypedData<Domain> { Domain = new Domain { Name = "Ether Mail", Version = "1", ChainId = 1, VerifyingContract = "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC" }, Types = MemberDescriptionFactory.GetTypesMemberDescription( typeof(Domain), typeof(Mail), typeof(Person)), PrimaryType = nameof(Mail), }; ``` `MemberDescriptionFactory.GetTypesMemberDescription` auto-generates the type schema from C# classes. Pass `typeof(Domain)` plus all struct types. Domain fields: `Name`, `Version`, `ChainId`, `VerifyingContract`, `Salt` (optional). ## Step 3: Sign and Recover ```csharp var signer = new Eip712TypedDataSigner(); var key = new EthECKey("private-key-hex"); var mail = new Mail { From = new Person { Name = "Cow", Wallet = "0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826" }, To = new Person { Name = "Bob", Wallet = "0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB" }, Contents = "Hello, Bob!" }; var signature = signer.SignTypedDataV4(mail, typedData, key); var recoveredAddress = signer.RecoverFromSignatureV4(mail, typedData, signature); // Verify bool isValid = key.GetPublicAddress().IsTheSameAddress(recoveredAddress); ``` The signature is a `0x`-prefixed hex string (132 chars = 65 bytes). ## Sign from JSON (No C# Types) When receiving EIP-712 data as JSON (e.g., from WalletConnect): ```csharp var typedDataJson = @"{ 'domain': { 'chainId': 1, 'name': 'Ether Mail', 'verifyingContract': '0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC', 'version': '1' }, 'message': { 'contents': 'Hello, Bob!', 'from': { 'name': 'Cow', 'wallet': '0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826' }, 'to': { 'name': 'Bob', 'wallet': '0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB' } }, 'primaryType': 'Mail', 'types': { 'EIP712Domain': [ { 'name': 'name', 'type': 'string' }, { 'name': 'version', 'type': 'string' }, { 'name': 'chainId', 'type': 'uint256' }, { 'name': 'verifyingContract', 'type': 'address' } ], 'Mail': [ { 'name': 'from', 'type': 'Person' }, { 'name': 'to', 'type': 'Person' }, { 'name': 'contents', 'type': 'string' } ], 'Person': [ { 'name': 'name', 'type': 'string' }, { 'name': 'wallet', 'type': 'address' } ] } }"; var key = new EthECKey("private-key-hex"); var signer = new Eip712TypedDataSigner(); var signature = signer.SignTypedDataV4(typedDataJson, key); var recoveredAddress = signer.RecoverFromSignatureV4(typedDataJson, signature); ``` ## ERC-2612 Permit Signature Define the Permit struct: ```csharp [Struct("Permit")] public class Permit { [Parameter("address", "owner", 1)] public string Owner { get; set; } [Parameter("address", "spender", 2)] public string Spender { get; set; } [Parameter("uint256", "value", 3)] public BigInteger Value { get; set; } [Parameter("uint256", "nonce", 4)] public BigInteger Nonce { get; set; } [Parameter("uint256", "deadline", 5)] public BigInteger Deadline { get; set; } } ``` Sign a permit: ```csharp var typedData = new TypedData<Domain> { Domain = new Domain { Name = "MyToken", Version = "1", ChainId = 1, VerifyingContract = "0x1234567890abcdef1234567890abcdef12345678" }, Types = MemberDescriptionFactory.GetTypesMemberDescription( typeof(Domain), typeof(Permit)), PrimaryType = nameof(Permit), }; var permit = new Permit { Owner = "0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826", Spender = "0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB", Value = BigInteger.Parse("1000000000000000000"), Nonce = 0, Deadline = BigInteger.Parse("1000000000000") }; var key = new EthECKey("private-key-hex"); var signer = new Eip712TypedDataSigner(); var signature = signer.SignTypedDataV4(permit, typedData, key); ``` ## Auto-Generated Schema Shortcut For simple structs without nesting, skip manual `TypedData` construction: ```csharp var domain = new Domain { Name = "Ether Mail", Version = "1", ChainId = 1, VerifyingContract = "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC" }; var signer = new Eip712TypedDataSigner(); var key = new EthECKey("private-key-hex"); var signature = signer.SignTypedData<Permit, Domain>(permit, domain, "Permit", key); ``` Manual verification of auto-generated signatures: ```csharp var encodedData = Eip712TypedDataEncoder.Current .EncodeTypedData(permit, domain, "Permit"); var recoveredAddress = new MessageSigner().EcRecover( Sha3Keccack.Current.CalculateHash(encodedData), signature); ``` ## Quick Reference | Method | Use Case | |---|---| | `SignTypedDataV4(message, typedData, key)` | Sign with C# typed structs | | `RecoverFromSignatureV4(message, typedData, sig)` | Recover address from typed struct signature | | `SignTypedDataV4(json, key)` | Sign from raw JSON | | `RecoverFromSignatureV4(json, sig)` | Recover address from JSON signature | | `SignTypedData<T, TDomain>(msg, domain, name, key)` | Sign with auto-generated schema | ## Common Patterns ### Verify a Signature ```csharp var expectedAddress = "0x..."; var recoveredAddress = signer.RecoverFromSignatureV4(message, typedData, signature); bool isValid = expectedAddress.IsTheSameAddress(recoveredAddress); ``` ### Multi-Chain Domain ```csharp var domain = new Domain { Name = "My Dapp", Version = "2", ChainId = 137, // Polygon VerifyingContract = "0x1111111111111111111111111111111111111111" }; ``` ## Verified Source All patterns from `tests/Nethereum.Signer.UnitTests/Eip712DocExampleTests.cs`.