feat: add eip-7702 auth list types

crates/eips/README.md

@@ -18,3 +18,4 @@ Contains constants, helpers, and basic data structures for consensus EIPs.
 - [EIP-7002](https://eips.ethereum.org/EIPS/eip-7002)
 - [EIP-7251](https://eips.ethereum.org/EIPS/eip-7251)
 - [EIP-7685](https://eips.ethereum.org/EIPS/eip-7685)
+- [EIP-7702](https://eips.ethereum.org/EIPS/eip-7702)

crates/eips/src/eip7702/auth_list.rs

@@ -0,0 +1,112 @@
+use core::ops::Deref;
+
+use alloy_primitives::{keccak256, Address, ChainId, Signature, SignatureError, B256};
+use alloy_rlp::{BufMut, Decodable, Encodable, Header, RlpEncodable};
+
+use super::constants::MAGIC;
+
+/// An EIP-7702 authorization list.
+pub type AuthorizationList = Vec<Authorization>;
+
+/// An EIP-7702 authorization.
+#[derive(Debug, Clone, RlpEncodable)]
+pub struct Authorization {
+    chain_id: ChainId,
+    address: Address,
+    nonce: OptionalNonce,
+    signature: Signature,
+}
+
+impl Authorization {
+    /// Get the `chain_id` for the authorization.
+    ///
+    /// # Note
+    ///
+    /// Implementers should check that this matches the current `chain_id` *or* is 0.
+    pub fn chain_id(&self) -> ChainId {
+        self.chain_id
+    }
+
+    /// Get the `address` for the authorization.
+    pub fn address(&self) -> &Address {
+        &self.address
+    }
+
+    /// Get the `nonce` for the authorization.
+    ///
+    /// # Note
+    ///
+    /// If this is `Some`, implementers should check that the nonce of the authority (see [`Self::recover_authority`]) is equal to this nonce.
+    pub fn nonce(&self) -> Option<u64> {
+        *self.nonce
+    }
+
+    /// Get the `signature` for the authorization.
+    pub fn signature(&self) -> &Signature {
+        &self.signature
+    }
+
+    /// Computes the authority prehash used to recover the authority from an authorization list item.
+    ///
+    /// The authority prehash is `keccak(MAGIC || rlp([chain_id, [nonce], address]))`
+    #[inline]
+    fn authority_prehash(&self) -> B256 {
+        #[derive(RlpEncodable)]
+        struct Auth {
+            chain_id: ChainId,
+            nonce: OptionalNonce,
+            address: Address,
+        }
+
+        let mut buf = Vec::new();
+        buf.put_u8(MAGIC);
+
+        Auth { chain_id: self.chain_id, nonce: self.nonce, address: self.address }.encode(&mut buf);
+
+        keccak256(buf)
+    }
+
+    /// Recover the authority for the authorization.
+    ///
+    /// # Note
+    ///
+    /// Implementers should check that the authority has no code.
+    pub fn recover_authority(&self) -> Result<Address, SignatureError> {
+        self.signature.recover_address_from_prehash(&self.authority_prehash())
+    }
+}
+
+/// An internal wrapper around an `Option<u64>` for optional nonces.
+///
+/// In EIP-7702 the nonce is encoded as a list of either 0 or 1 items, where 0 items means that no nonce was specified (i.e. `None`). If there is 1 item, this is the same as `Some`.
+///
+/// The wrapper type is used for RLP encoding and decoding.
+#[derive(Debug, Copy, Clone)]
+struct OptionalNonce(Option<u64>);
+
+impl Encodable for OptionalNonce {
+    fn encode(&self, out: &mut dyn BufMut) {
+        match self.0 {
+            Some(nonce) => {
+                Header { list: true, payload_length: nonce.length() }.encode(out);
+                nonce.encode(out);
+            }
+            None => Header { list: true, payload_length: 0 }.encode(out),
+        }
+    }
+}
+
+impl Decodable for OptionalNonce {
+    fn decode(buf: &mut &[u8]) -> alloy_rlp::Result<Self> {
+        let list: Vec<u64> = Vec::decode(buf)?;
+        Ok(Self(list.first().copied()))
+    }
+}
+
+impl Deref for OptionalNonce {
+    type Target = Option<u64>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}

crates/eips/src/eip7702/constants.rs

@@ -0,0 +1,18 @@
+//! [EIP-7702] constants.
+//!
+//! [EIP-7702]: https://eips.ethereum.org/EIPS/eip-7702
+
+/// Identifier for EIP7702's set code transaction.
+///
+/// See also [EIP-7702](https://eips.ethereum.org/EIPS/eip-7702).
+pub const EIP7702_TX_TYPE_ID: u8 = 4;
+
+/// Magic number used to calculate an EIP7702 authority.
+///
+/// See also [EIP-7702](https://eips.ethereum.org/EIPS/eip-7702).
+pub const MAGIC: u8 = 0x05;
+
+/// An additional gas cost per EIP7702 authorization list item.
+///
+/// See also [EIP-7702](https://eips.ethereum.org/EIPS/eip-7702).
+pub const PER_AUTH_BASE_COST: u64 = 2500;

crates/eips/src/eip7702/mod.rs

@@ -0,0 +1,8 @@
+//! [EIP-7702] constants, helpers, and types.
+//!
+//! [EIP-7702]: https://eips.ethereum.org/EIPS/eip-7702
+
+mod auth_list;
+pub use auth_list::*;
+
+pub mod constants;

crates/eips/src/lib.rs

@@ -26,11 +26,11 @@ pub mod eip2935;
 
 pub mod eip4788;
 
-pub mod eip4895;
-
 pub mod eip4844;
 pub use eip4844::{calc_blob_gasprice, calc_excess_blob_gas};
 
+pub mod eip4895;
+
 pub mod eip6110;
 pub mod merge;
 
@@ -39,3 +39,5 @@ pub mod eip7002;
 pub mod eip7251;
 
 pub mod eip7685;
+
+pub mod eip7702;