Support Pectra EVM Type 4 Transaction Encoding (EIP-7702)

[0xivanov]

Context

Ethereum's Pectra upgrade (EIP-7600) activated on May 7, 2025. To maintain EVM compatibility, Hiero must adopt the applicable EIPs from this release.

HIP-1341 defines the Hiero adoption of the Pectra release, distinguishing which EIPs are applicable to Hiero versus non-applicable. Of the twelve Pectra EIPs, three are applicable:

EIP	Title	SDK Impact
EIP-7702	Set EOA Account Code	Yes — see HIP-1340
EIP-2537	Precompile for BLS12-381 curve operations	No — consensus node change only
EIP-7623	Increase calldata cost	No — consensus node and JSON-RPC relay change only

The remaining nine EIPs are non-applicable to Hiero (blob support, Ethereum validators, or ETH 2.0 features not present in Hiero).

Dependencies

• HIP-1341: Support for Ethereum Pectra Release — umbrella HIP
• HIP-1340: EOA Code Delegation — SDK design specification for EIP-7702
• Consensus node epic #20043 — upstream consensus node work; SDK integration requires a consensus node release that includes EIP-7702 support

What the SDKs Will Implement

All SDK work is driven by HIP-1340, which implements EIP-7702 (EOA Code Delegation). This feature allows EOAs to delegate code execution to a smart contract, enabling advanced account abstraction use cases such as transaction batching, gas sponsorship, and privilege de-escalation.

New Types

Authorization — Represents an EIP-7702 authorization tuple used to delegate code execution from an EOA to a smart contract address.

EthereumTransactionDataEip7702 — Encodes an Ethereum Type 4 transaction (EIP-7702) that includes an authorization list.

Updated APIs

AccountCreateTransaction — New delegationAddress field (nullable EvmAddress) that sets the EOA code delegation on account creation.

AccountUpdateTransaction — New delegationAddress field (nullable EvmAddress) that sets or clears the EOA code delegation. Setting to 20 zero-bytes or null clears any existing delegation.

AccountInfo — New delegationAddress field (nullable, immutable EvmAddress) returned when querying an account that has a delegation set.

Full API specification is in proposals/hips/hip-1340.md.

SDK Implementation Tasks

Each SDK must:

• Add Authorization type
• Add EthereumTransactionDataEip7702 type
• Update AccountCreateTransaction with delegationAddress setter/getter
• Update AccountUpdateTransaction with delegationAddress setter/getter (including null/zero-address clear)
• Update AccountInfo with delegationAddress field
• Add unit tests
• Add integration tests (against a network that supports Pectra)

[manishdait]

@0xivanov, Can I work on this

[mustafauzunn]

This is duplicate of #2541 and we already have a PR for it #2558

[0xivanov]

I'd suggest closing the old issue since it might be outdated with some new updates in the HIP

[mustafauzunn]

I prefer to keep the old issue and PR. And if needed to refactor or enhance the PR