split into two FIPs; WIP.

Author: raulk

FIPS/fip-nnnn-eam-eeoa.md

@@ -0,0 +1,205 @@
+---
+fip: <to be assigned>
+title: Ethereum Address Manager (EAM) and Ethereum Externally Owned Account (EEOA)
+author: Raúl Kripalani (@raulk), Steven Allen (@stebalien)
+discussions-to: <URL>
+status: Draft
+type: Technical Core
+category: Core
+created: 2022-12-02
+spec-sections:
+requires: N/A
+replaces: N/A
+---
+
+# Ethereum Address Manager (EAM) and Ethereum Externally Owned Account (EEOA)
+
+## Simple Summary
+
+TODO.
+
+## Abstract
+
+TODO.
+
+## Change Motivation
+
+TODO.
+
+
+## Specification: Ethereum Address Manager (EAM)
+
+We introduce the **Ethereum Address Manager (EAM) actor** as a singleton
+built-in actor sitting at ID address `10`. This actor fulfills two purposes:
+
+1. It manages the f4 address class namespace under its ID address (i.e. f410),
+   assigning Ethereum-compatible addresses under it.
+2. It acts as the entrypoint for deployment of EVM smart contracts, respecting
+   Ethereum rules and semantics.
+
+For the latter, this actor offers two Filecoin methods `Create` and `Create2`,
+equivalent to their Ethereum counterparts. In Ethereum, `CREATE` and `CREATE2`
+differ in their address generation rules:
+
+- `CREATE` uses the protocol-provided nonce to derive the contract's address,
+  and is thus non-deterministic.
+- `CREATE2` takes an explicit user-provided salt to compute a deterministic
+  address. It is suitable for counterfactual deployments.
+
+### Deployment
+
+The EAM is deployed as a singleton actor under ID address `10`. The deployment
+happens during the state migration where this FIP goes live.
+
+The EAM is allow-listed in the Init Actor as a caller of its `Exec4` method,
+specified in FIP-0048.
+
+### Procedure
+
+The procedure to deploy EVM smart contracts to the Filecoin chain is as follows:
+
+1. The contract deployment message enters the Ethereum Address Manager (EAM)
+   through the `Create` or `Create2` method. 
+2. The EAM computes an `f410` address according to the heuristics of the invoked
+   method (see below). The resulting f410 address is semantically equivalent to
+   the one Ethereum would've generated for the same inputs, thus retaining tool
+   compatibility.
+2. The EAM invokes the Init actor's `Exec4` method (see [FIP-0048 (f4 Address
+   Class)]), supplying the CodeCID of the EVM runtime actor, the constructor
+   parameters (EVM init code and original creator address), and the assigned
+   f410 address.
+
+### State
+
+None.
+
+### Actor interface (methods)
+
+#### Method number `1` (`Create`)
+
+Deploys a smart contract taking EVM init bytecode and accepting a nonce from the
+user. Refer to [Procedure](#procedure) for a description of the deployment
+procedure.
+
+The `create` method is used in two cases:
+
+1. When an EEOA actor deploys a smart contract by submitting a native Ethereum
+   transaction containing initcode through the Ethereum JSON-RPC API endpoint.
+   The endpoint detects the deployment operation, and translates the Ethereum
+   transaction to an `EAM#Create` Filecoin message.
+2. When an EVM smart contract calls the `CREATE` opcode.
+
+Note that this differs from Ethereum in that we take a user-provided nonce as a
+parameter. This is necessary so that the EVM runtime actor can supply the
+contract's nonce when handling `CREATE` to the EAM. This is a mild departure
+from Ethereum's behavior as it allows an EEOA to deploy a contract with an
+arbitrary nonce. No safety violations are possible because the system guarantees
+that we don't deploy over an existing actor anyway (those constraints are
+enforced by the init actor and the FVM itself).
+
+_Input parameters_
+
+```rust
+// DAG-CBOR tuple encoded.
+pub struct CreateParams {
+    /// EVM init code.
+    pub initcode: Vec<u8>,
+    /// Nonce with which to create this smart contract.
+    pub nonce: u64,
+}
+```
+
+_Return value_
+
+```rust
+// DAG-CBOR tuple encoded.
+pub struct Return {
+    /// The ID of the EVM runtime actor that was constructed.
+    pub actor_id: ActorID,
+    /// Its f2 address.
+    pub robust_address: Address,
+    /// Its Ethereum address, translatable to an f410 address.
+    pub eth_address: [u8; 20],
+}
+```
+
+_Errors_
+
+TODO.
+
+#### Method number `2` (`Create2`)
+
+Deploys a smart contract taking EVM init bytecode and accepting a user-provided
+salt to generate a deterministic Ethereum address (translatable to an f410
+address). Refer to [Procedure](#procedure) for a description of the deployment
+procedure.
+
+`Create2` is used in a single case: to handle the `CREATE2` opcode while
+executing EVM bytecode within the EVM runtime actor.
+
+_Input parameters_
+
+```rust
+pub struct Create2Params {
+    /// EVM init code.
+    pub initcode: Vec<u8>,
+    /// User provided salt.
+    pub salt: [u8; 32],
+}
+```
+
+_Return value_
+
+Same as [`Create`](#method-number-1-create).
+
+## Specification: Ethereum Externally Owned Account (EEOA)
+
+TODO (@aayush).
+
+## Design Rationale
+
+> TODO:
+> - Flat vs nested contract deployment model.
+> - ...
+
+## Backwards Compatibility
+
+TODO.
+
+## Test Cases
+
+## Security Considerations
+
+TODO.
+
+## Incentive Considerations
+
+TODO.
+
+## Product Considerations
+
+TODO.
+
+## Implementation
+
+TODO.
+
+## Appendix A: Notable differences between FEVM and EVM for smart contract developers
+
+TODO.
+
+## Appendix B: Upgrades
+
+TODO.
+
+## Copyright
+
+Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).
+
+
+[`filecoin-project/builtin-actors`]: https://github.com/filecoin-project/builtin-actors
+[FRC42 calling convention]: https://github.com/filecoin-project/FIPs/blob/master/FRCs/frc-0042.md
+[FIP-0048 (f4 Address Class)]: https://github.com/filecoin-project/FIPs/blob/master/FIPS/fip-0048.md
+[Contract ABI spec]: https://docs.soliditylang.org/en/v0.5.3/abi-spec.html
+[Ethereum Paris hard fork]: https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/paris.md
+[FIP-0049 (Actor events)]: https://github.com/filecoin-project/FIPs/blob/master/FIPS/fip-0049.md