Ethereum Foundation has a new EIP under review that proposes native key delegation for Externally Owned Accounts (EOAs), a protocol-level enhancement that could reshape account abstraction and wallet UX across the ecosystem.

# Native Key Delegation for EOAs — Conceptual Walkthrough
# NOTE: This EIP is in draft/review stage. The interface below is illustrative
# and based on the proposal's described mechanics. No production implementation
# exists yet — this is meant to help developers understand the design space.

# -----------------------------------------------------------
# STEP 1: Understanding the delegation model
# -----------------------------------------------------------
# The EIP introduces a new transaction type (or precompile) that allows
# an EOA to register a delegate key with scoped permissions.
# Think of it as: "My main key authorizes THIS secondary key to sign
# transactions on my behalf, subject to THESE constraints."

# Pseudo-representation of a delegation registration:
# delegation = {
#     "delegator": "0xYourEOA",           # The primary EOA address
#     "delegate":  "0xSessionKey",         # The authorized secondary public key
#     "scope": {                            # Permission boundaries
#         "allowed_targets": ["0xDAppContract"],  # Optional: restrict to specific contracts
#         "max_value": 0,                   # Optional: cap ETH value per tx
#         "expiry": 1744300800               # Optional: Unix timestamp expiration
#     },
#     "nonce": 1,                           # Delegation nonce (for revocation/rotation)
#     "signature": "0xSignedByDelegatorKey" # Signed by the EOA's primary key
# }

# -----------------------------------------------------------
# STEP 2: Registering a delegate key (conceptual TX)
# -----------------------------------------------------------
# The delegator EOA broadcasts a special transaction (new TX type)
# that registers the delegation in protocol state.

# from web3 import Web3
# w3 = Web3(Web3.HTTPProvider('http://localhost:8545'))
#
# # Build the delegation payload
# delegation_payload = {
#     'delegate': '0xAbC123...SessionKey',
#     'scope': {
#         'allowed_targets': ['0xDef456...DAppContract'],
#         'max_value': 0,
#         'expiry': 1744300800
#     }
# }
#
# # Sign and send using the new transaction type (TBD in EIP spec)
# tx_hash = w3.eth.send_delegation(
#     delegator='0x789...YourEOA',
#     delegation=delegation_payload,
#     private_key=DELEGATOR_PRIVATE_KEY
# )
# print(f'Delegation registered: {tx_hash.hex()}')

# -----------------------------------------------------------
# STEP 3: Delegate key signs a transaction on behalf of the EOA
# -----------------------------------------------------------
# Once registered, the delegate key can submit transactions that
# are validated by the protocol as if they came from the delegator EOA.
# The "from" address resolves to the delegator, but the signature
# is from the delegate key.

# delegated_tx = {
#     'from': '0x789...YourEOA',           # Appears as the original EOA
#     'to': '0xDef456...DAppContract',
#     'data': contract.functions.doSomething(42).build_transaction()['data'],
#     'delegated_by': '0xAbC123...SessionKey',  # New field: identifies delegate
# }
#
# # Signed with the SESSION key, not the primary key
# tx_hash = w3.eth.send_delegated_transaction(
#     delegated_tx,
#     private_key=SESSION_PRIVATE_KEY
# )
# print(f'Delegated tx sent: {tx_hash.hex()}')

# -----------------------------------------------------------
# STEP 4: Revoking a delegate key
# -----------------------------------------------------------
# The delegator can revoke at any time by submitting a revocation
# transaction or incrementing the delegation nonce.

# revoke_tx = w3.eth.revoke_delegation(
#     delegator='0x789...YourEOA',
#     delegate='0xAbC123...SessionKey',
#     private_key=DELEGATOR_PRIVATE_KEY
# )
# print(f'Delegation revoked: {revoke_tx.hex()}')

# -----------------------------------------------------------
# STEP 5: Verifying delegation on-chain (for contract devs)
# -----------------------------------------------------------
# Smart contracts interacting with delegated transactions may want
# to inspect delegation metadata. The EIP is expected to expose
# delegation info via a new opcode or precompile.

# # Solidity (conceptual)
# // Check if msg.sender's transaction was delegated
# // address delegate = DELEGATION_PRECOMPILE.getDelegateFor(msg.sender);
# // require(delegate != address(0), "Not a delegated call");

# -----------------------------------------------------------
# KEY TAKEAWAYS FOR DEVELOPERS:
# -----------------------------------------------------------
# - This is a PROTOCOL-LEVEL change, not a smart contract standard.
#   It requires client updates (geth, nethermind, etc.) and a hard fork.
# - It does NOT replace ERC-4337 or smart contract wallets — it
#   complements them by giving EOAs a subset of AA capabilities.
# - Session keys, key rotation, and scoped permissions become native.
# - Watch the EIP discussion thread for spec finalization and
#   testnet availability.
# - If you're building wallets or dApps with session key patterns,
#   this EIP is directly relevant to your architecture decisions.