feat: add eip2124 forkid

Cargo.toml

@@ -49,3 +49,6 @@ arbitrary = "1.3"
 # for 7702 signed authorization list arbitrary
 k256 = { version = "0.13", default-features = false, features = ["ecdsa"] }
 rand = "0.8"
+
+# misc
+thiserror = { version = "2.0.0", default-features = false }

crates/eip2124/Cargo.toml

@@ -0,0 +1,44 @@
+[package]
+name = "alloy-eip2124"
+description = "Fork identifier for chain compatibility checks"
+
+version = "0.1.0"
+edition.workspace = true
+rust-version.workspace = true
+authors.workspace = true
+license.workspace = true
+homepage.workspace = true
+repository.workspace = true
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+
+[lints]
+workspace = true
+
+[dependencies]
+alloy-primitives = { workspace = true, features = ["rlp"] }
+alloy-rlp = { workspace = true, features = ["derive"] }
+
+# serde
+serde = { workspace = true, optional = true }
+
+# used for forkid
+crc = "3"
+
+# arbitrary
+arbitrary = { workspace = true, features = ["derive"], optional = true }
+rand = { workspace = true, optional = true }
+
+thiserror.workspace = true
+
+[dev-dependencies]
+arbitrary = { workspace = true, features = ["derive"] }
+alloy-rlp = { workspace = true, features = ["arrayvec"] }
+
+[features]
+default = ["std"]
+std = ["alloy-primitives/std", "alloy-rlp/std", "serde?/std", "thiserror/std"]
+serde = ["dep:serde", "alloy-primitives/serde"]
+arbitrary = ["std", "dep:arbitrary", "dep:rand", "alloy-primitives/arbitrary"]