Eip7702

bool isDelegated = await authorisationService.IsDelegatedAccountAsync(address);
string delegateAddress = await authorisationService.GetDelegatedAccountAddressAsync(address);

Checks if account code starts with 0xef0100 (delegation prefix).

Remove Delegation

var receipt = await authorisationService
    .RemoveAuthorisationRequestAndWaitForReceiptAsync();

Sponsored Delegation

Sponsor pays gas, sponsored account signs only the authorization:

using Nethereum.Accounts;
using Nethereum.Signer;

var sponsor = new Account("0xSPONSOR_KEY", Chain.MainNet);
var web3 = new Web3(sponsor, "https://mainnet.infura.io/v3/YOUR_KEY");

var sponsoredKey = new EthECKey("0xSPONSORED_PRIVATE_KEY");

var sponsorService = new EIP7022SponsorAuthorisationService(
    web3.TransactionManager, web3.Eth);

var receipt = await sponsorService
    .AuthoriseSponsoredRequestAndWaitForReceiptAsync(
        sponsoredKey,
        "0xDelegateContractAddress",
        useUniversalZeroChainId: true,
        brandNewAccount: true);

Batch Sponsorship

var keys = new EthECKey[] { key1, key2, key3 };
var receipt = await sponsorService
    .AuthoriseBatchSponsoredRequestAndWaitForReceiptAsync(
        keys, "0xDelegateContract", useUniversalZeroChainId: true, brandNewAccount: true);

Low-Level: Manual Authorization

using Nethereum.Model;
using Nethereum.Signer;

// 1. Create authorization
var authorisation = new Authorisation7702
{
    ChainId = 1,                          // 0 for universal
    Address = "0xDelegateContractAddress",
    Nonce = 0                              // must match EOA's current nonce
};

// 2. Sign authorization
var ecKey = new EthECKey("0xYOUR_PRIVATE_KEY");
var authSigner = new Authorisation7702Signer();
var signedAuth = authSigner.SignAuthorisation(ecKey, authorisation);

// 3. Build Type 4 transaction
var tx = new Transaction7702(
    chainId: 1, nonce: 0,
    maxPriorityFeePerGas: BigInteger.Parse("2000000000"),
    maxFeePerGas: BigInteger.Parse("100000000000"),
    gasLimit: 100000,
    receiverAddress: ecKey.GetPublicAddress(),
    amount: BigInteger.Zero, data: null,
    accessList: new List<AccessListItem>(),
    authorisationList: new List<Authorisation7702Signed> { signedAuth });

// 4. Sign and broadcast
var txSigner = new Transaction7702Signer();
var signedTxHex = txSigner.SignTransaction(ecKey, tx);
await web3.Eth.Transactions.SendRawTransaction.SendRequestAsync("0x" + signedTxHex);

Inline Authorization (with Contract Calls)

Attach authorization to the same transaction that calls the delegate:

var executeFunction = new ExecuteFunction
{
    Calls = batchCalls,
    Gas = 1000000,  // must set gas manually
    AuthorisationList = new List<Authorisation>
    {
        new Authorisation { Address = "0xDelegateContractAddress" }
    }
};
var receipt = await contractService.ExecuteRequestAndWaitForReceiptAsync(executeFunction);

Unsigned Authorisation is signed automatically by the transaction manager.

Recover Signer from Authorization

var signerAddress = EthECKeyBuilderFromSignedAuthorisation.RecoverSignerAddress(signedAuth);

Gas Costs

• Per authorization base: 12,500 gas
• Per account (new or existing): 25,000 gas

int extraGas = AuthorisationGasCalculator.CalculateGasForAuthorisationDelegation(
    numberOfNew: 3, numberOfExisting: 1);

Key Facts

• Type byte: 0x04
• Delegation prefix in account code: 0xef0100 + 20-byte address
• Uses EIP-1559 fee model (maxFeePerGas + maxPriorityFeePerGas)
• Delegation persists across transactions until explicitly removed
• No delegation chaining (only first level resolved)
• Hardware wallets (Ledger, Trezor) and cloud KMS (AWS, Azure) all support SignAsync(Transaction7702)

Required Usings

using Nethereum.Web3;
using Nethereum.Web3.Accounts;
using Nethereum.Accounts;
using Nethereum.Model;
using Nethereum.Signer;
using Nethereum.RPC.Eth.DTOs;
using Nethereum.RPC.TransactionManagers;
using System.Collections.Generic;
using System.Numerics;