feat: snip-12 typed data parsing and hashing

README.md

@@ -95,21 +95,23 @@ Examples can be found in the [examples folder](./examples):
 
 7. [Encoding and decoding Cairo types](./examples/serde.rs)
 
-8. [Batched JSON-RPC requests](./examples/batch.rs)
+8. [Parse a SNIP-12 message and compute its hash](./examples/snip_12_json.rs)
 
-9. [Call a contract view function](./examples/erc20_balance.rs)
+9. [Batched JSON-RPC requests](./examples/batch.rs)
 
-10. [Deploy an Argent X account to a pre-funded address](./examples/deploy_argent_account.rs)
+10. [Call a contract view function](./examples/erc20_balance.rs)
 
-11. [Inspect public key with Ledger](./examples/ledger_public_key.rs)
+11. [Deploy an Argent X account to a pre-funded address](./examples/deploy_argent_account.rs)
 
-12. [Deploy an OpenZeppelin account with Ledger](./examples/deploy_account_with_ledger.rs)
+12. [Inspect public key with Ledger](./examples/ledger_public_key.rs)
 
-13. [Transfer ERC20 tokens with Ledger](./examples/transfer_with_ledger.rs)
+13. [Deploy an OpenZeppelin account with Ledger](./examples/deploy_account_with_ledger.rs)
 
-14. [Parsing a JSON-RPC request on the server side](./examples/parse_jsonrpc_request.rs)
+14. [Transfer ERC20 tokens with Ledger](./examples/transfer_with_ledger.rs)
 
-15. [Inspecting a erased provider-specific error type](./examples/downcast_provider_error.rs)
+15. [Parsing a JSON-RPC request on the server side](./examples/parse_jsonrpc_request.rs)
+
+16. [Inspecting a erased provider-specific error type](./examples/downcast_provider_error.rs)
 
 ## License
 

examples/snip_12_json.rs

@@ -0,0 +1,44 @@
+use starknet::{core::types::TypedData, macros::felt};
+
+fn main() {
+    let raw = r#"{
+  "types": {
+    "StarknetDomain": [
+      { "name": "name", "type": "shortstring" },
+      { "name": "version", "type": "shortstring" },
+      { "name": "chainId", "type": "shortstring" },
+      { "name": "revision", "type": "shortstring" }
+    ],
+    "Example Message": [
+      { "name": "Name", "type": "string" },
+      { "name": "Some Array", "type": "u128*" },
+      { "name": "Some Object", "type": "My Object" }
+    ],
+    "My Object": [
+      { "name": "Some Selector", "type": "selector" },
+      { "name": "Some Contract Address", "type": "ContractAddress" }
+    ]
+  },
+  "primaryType": "Example Message",
+  "domain": {
+    "name": "Starknet Example",
+    "version": "1",
+    "chainId": "SN_MAIN",
+    "revision": "1"
+  },
+  "message": {
+    "Name": "some name",
+    "Some Array": [1, 2, 3, 4],
+    "Some Object": {
+      "Some Selector": "transfer",
+      "Some Contract Address": "0x0123"
+    }
+  }
+}"#;
+
+    let typed_data = serde_json::from_str::<TypedData>(raw).unwrap();
+    println!("SNIP-12 revision: {}", typed_data.revision());
+
+    let message_hash = typed_data.message_hash(felt!("0x1234")).unwrap();
+    println!("SNIP-12 hash: {:#064x}", message_hash);
+}

starknet-core/Cargo.toml

@@ -22,7 +22,9 @@ starknet-core-derive = { version = "0.1.0", path = "../starknet-core-derive" }
 base64 = { version = "0.21.0", default-features = false, features = ["alloc"] }
 crypto-bigint = { version = "0.5.1", default-features = false }
 flate2 = { version = "1.0.25", optional = true }
+foldhash = { version = "0.1.4", default-features = false }
 hex = { version = "0.4.3", default-features = false, features = ["alloc"] }
+indexmap = { version = "2.7.0", default-features = false, features = ["serde"] }
 num-traits = { version = "0.2.19", default-features = false }
 serde = { version = "1.0.160", default-features = false, features = ["derive"] }
 serde_json = { version = "1.0.96", default-features = false, features = ["alloc", "raw_value"] }
@@ -42,7 +44,7 @@ wasm-bindgen-test = "0.3.34"
 
 [features]
 default = ["std"]
-std = ["dep:flate2", "starknet-crypto/std", "starknet-types-core/std"]
+std = ["dep:flate2", "starknet-crypto/std", "starknet-types-core/std", "indexmap/std"]
 no_unknown_fields = []
 
 [[bench]]

starknet-core/src/codec.rs

@@ -1,5 +1,6 @@
 use alloc::{boxed::Box, fmt::Formatter, format, string::*, vec::*};
 use core::{fmt::Display, mem::MaybeUninit};
+use starknet_crypto::{PedersenHasher, PoseidonHasher};
 
 use num_traits::ToPrimitive;
 
@@ -117,12 +118,31 @@ pub struct Error {
     repr: Box<str>,
 }
 
+// This implementation is useful for encoding single-felt types.
+impl FeltWriter for Felt {
+    fn write(&mut self, felt: Felt) {
+        *self = felt;
+    }
+}
+
 impl FeltWriter for Vec<Felt> {
     fn write(&mut self, felt: Felt) {
         self.push(felt);
     }
 }
 
+impl FeltWriter for PedersenHasher {
+    fn write(&mut self, felt: Felt) {
+        self.update(felt);
+    }
+}
+
+impl FeltWriter for PoseidonHasher {
+    fn write(&mut self, felt: Felt) {
+        self.update(felt);
+    }
+}
+
 impl Encode for Felt {
     fn encode<W: FeltWriter>(&self, writer: &mut W) -> Result<(), Error> {
         writer.write(*self);

starknet-core/src/types/mod.rs

@@ -11,6 +11,10 @@ mod conversions;
 
 mod serde_impls;
 
+/// SNIP-12 typed data.
+pub mod typed_data;
+pub use typed_data::TypedData;
+
 // TODO: better namespacing of exports?
 mod codegen;
 pub use codegen::{