enable webassembly support

Cargo.toml

@@ -48,6 +48,7 @@ incrementalmerkletree = "0.8.1"
 zcash_spec = "0.2.1"
 zip32 = { version = "0.2.0", default-features = false }
 visibility = "0.1.1"
+wasm-bindgen = { version = "0.2", optional = true }
 
 # Circuit
 halo2_gadgets = { git = "https://github.com/QED-it/halo2", branch = "zsa1", optional = true }
@@ -79,17 +80,22 @@ inferno = { version = "0.11", default-features = false, features = ["multithread
 #clap = "=4.2.0" #Pinned: Used by inferno. Later version requires Rust 1.70
 pprof = { version = "0.11", features = ["criterion", "flamegraph"] }
 
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+getrandom = { version = "0.2", default-features = false, features = ["js"] }
+
 [lib]
+crate-type = ["cdylib", "rlib"]
 bench = false
 
 [features]
-default = ["circuit", "multicore", "std"]
+default = ["circuit", "std"]  # multicore is opt-in; wasm builds disable it to avoid atomics issues
 std = ["core2/std", "group/wnaf-memuse", "reddsa/std"]
 circuit = ["dep:halo2_gadgets", "dep:halo2_proofs", "std"]
 unstable-frost = []
 multicore = ["halo2_proofs?/multicore"]
 dev-graph = ["halo2_proofs?/dev-graph", "image", "plotters"]
 test-dependencies = ["proptest", "rand/std"]
+wasm = ["wasm-bindgen"]
 
 [[bench]]
 name = "note_decryption"

pkg/package.json

@@ -0,0 +1,38 @@
+{
+  "name": "orchard",
+  "type": "module",
+  "collaborators": [
+    "Sean Bowe <sean@electriccoin.co>",
+    "Jack Grigg <jack@electriccoin.co>",
+    "Daira-Emma Hopwood <daira@jacaranda.org>",
+    "Ying Tong Lai",
+    "Kris Nuttycombe <kris@electriccoin.co>"
+  ],
+  "description": "The Orchard shielded transaction protocol",
+  "version": "0.11.0",
+  "license": "MIT OR Apache-2.0",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/zcash/orchard"
+  },
+  "files": [
+    "orchard_bg.wasm",
+    "orchard.js",
+    "orchard_bg.js",
+    "orchard.d.ts",
+    "LICENSE-APACHE",
+    "LICENSE-MIT"
+  ],
+  "main": "orchard.js",
+  "types": "orchard.d.ts",
+  "sideEffects": [
+    "./orchard.js",
+    "./snippets/*"
+  ],
+  "keywords": [
+    "zcash"
+  ],
+  "dependencies": {
+    "bip39": "^3.0.4"
+  }
+}

pkg/test-derive.js

@@ -0,0 +1,65 @@
+#!/usr/bin/env node
+/*
+ * Minimal Node.js test for the full Orchard key/address derivation pipeline using a BIP39 mnemonic.
+ *
+ * Steps:
+ *   1) derive_spending_key(seed: Uint8Array, coinType: number, account: number) -> spendingKey
+ *   2) derive_full_viewing_key(spendingKey: Uint8Array) -> fullViewingKey
+ *   3) derive_address(fullViewingKey: Uint8Array, diversifierIndex: number) -> rawAddress
+ *
+ * Prerequisites:
+ *   npm install bip39
+ *   node --experimental-wasm-modules test-derive.js
+ */
+import { readFile } from 'fs/promises';
+import path from 'path';
+import { fileURLToPath } from 'url';
+import * as orchard from './orchard_bg.js';
+import bip39 from 'bip39';
+
+// In ES modules, compute __dirname relative to this file
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+async function main() {
+  // Load and instantiate the WebAssembly module manually
+  // Resolve the .wasm path relative to this script's directory
+  const wasmPath = path.resolve(__dirname, 'orchard_bg.wasm');
+  const wasmBytes = await readFile(wasmPath);
+  // Provide the two JS functions the .wasm expects as imports
+  const importObject = {
+    './orchard_bg.js': {
+      __wbindgen_string_new: orchard.__wbindgen_string_new,
+      __wbindgen_object_drop_ref: orchard.__wbindgen_object_drop_ref,
+    },
+  };
+  const { instance } = await WebAssembly.instantiate(wasmBytes, importObject);
+  orchard.__wbg_set_wasm(instance.exports);
+
+  // Example BIP39 mnemonic (12 words)
+  const mnemonic = 'abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about';
+  // Derive a 64-byte seed from the mnemonic
+  const seedBuffer = await bip39.mnemonicToSeed(mnemonic);
+  const seed = new Uint8Array(seedBuffer);
+
+  const coinType = 1;
+  const account = 0;
+
+  // Derive the Orchard spending key
+  const spendingKey = orchard.derive_spending_key(seed, coinType, account);
+  console.log('Spending key (hex):', Buffer.from(spendingKey).toString('hex'));
+
+  // Derive the full viewing key from the spending key
+  const fullViewingKey = orchard.derive_full_viewing_key(spendingKey);
+  console.log('Full viewing key (hex):', Buffer.from(fullViewingKey).toString('hex'));
+
+  // Derive a raw Orchard payment address (using diversifier index = 0)
+  const diversifierIndex = 0;
+  const rawAddress = orchard.derive_address(fullViewingKey, diversifierIndex);
+  console.log('Raw address (hex):', Buffer.from(rawAddress).toString('hex'));
+}
+
+main().catch(err => {
+  console.error(err);
+  process.exit(1);
+});

src/lib.rs

@@ -100,3 +100,11 @@ impl Proof {
         Proof(bytes)
     }
 }
+#[cfg(test)]
+mod key_test;
+
+// WASM-bindgen: derive Orchard address from a spending key
+#[cfg(feature = "wasm")]
+mod wasm_bindings;
+#[cfg(feature = "wasm")]
+pub use wasm_bindings::derive_orchard_address;