1 files changed, 66 insertions, 0 deletions
diff --git a/packages/meshbay-client/src/argon2-wasm.js b/packages/meshbay-client/src/argon2-wasm.js
new file mode 100644
index 0000000..c68e994
--- /dev/null
+++ b/packages/meshbay-client/src/argon2-wasm.js
@@ -0,0 +1,66 @@
+/**
+ * Argon2id for the main process, from the page's own WebAssembly build.
+ *
+ * Electron's Node is built on BoringSSL, which has no Argon2: `crypto.argon2`
+ * exists there and refuses (`ERR_CRYPTO_ARGON2_NOT_SUPPORTED`) — found by
+ * signing in to the real application, since a plain Node has it. The vendored
+ * build the page already runs is the one implementation both sides can share,
+ * which also makes their agreement a matter of construction.
+ */
+
+'use strict';
+
+const fs = require('node:fs');
+const path = require('node:path');
+
+let ready = null;
+
+/**
+ * The emscripten loader reads its options from a global `Module` (through
+ * `self`) when it is required, and again while the WebAssembly instantiates,
+ * which is asynchronous. Both globals are set for that time only — until the
+ * first derivation has run — so nothing else in this process sees them after.
+ */
+function load(vendorDir) {
+  if (ready) return ready;
+  const saved = {};
+  for (const name of ['self', 'Module']) {
+    saved[name] = Object.prototype.hasOwnProperty.call(globalThis, name)
+      ? { value: globalThis[name] } : null;
+  }
+  const restore = () => {
+    for (const [name, was] of Object.entries(saved)) {
+      if (was) globalThis[name] = was.value; else delete globalThis[name];
+    }
+  };
+  globalThis.Module = { wasmBinary: fs.readFileSync(path.join(vendorDir, 'argon2.wasm')) };
+  globalThis.self = globalThis;
+  ready = (async () => {
+    try {
+      const lib = require(path.join(vendorDir, 'argon2.min.js'));
+      // One derivation at the lowest cost: the instance exists once it returns.
+      await lib.hash({ pass: 'x', salt: new Uint8Array(8), time: 1, mem: 8,
+                       hashLen: 16, type: lib.ArgonType.Argon2id });
+      return lib;
+    } finally {
+      restore();
+    }
+  })();
+  ready.catch(() => { ready = null; });
+  return ready;
+}
+
+/** `(password, salt, params) => Promise<Buffer>` over the vendored build. */
+function wasmArgon2(vendorDir) {
+  return async (password, salt, { memory, passes, parallelism, tagLength }) => {
+    const a = await load(vendorDir);
+    const out = await a.hash({
+      pass: String(password), salt: new Uint8Array(salt),
+      time: passes, mem: memory, parallelism, hashLen: tagLength,
+      type: a.ArgonType.Argon2id,
+    });
+    return Buffer.from(out.hash);
+  };
+}
+
+module.exports = { wasmArgon2 };