diff --git a/shims/btime.js b/shims/btime.js
new file mode 100644
index 0000000..4e8582b
--- /dev/null
+++ b/shims/btime.js
@@ -0,0 +1,5 @@
+// Shim for the btime native module (file birth time)
+// Obsidian wraps this in try/catch: try{this.btime=window.require("btime")}catch(e){}
+// Returning null causes graceful degradation  -  mtime is used instead.
+
+export const btimeShim = null;
diff --git a/shims/crypto/create-hash.js b/shims/crypto/create-hash.js
new file mode 100644
index 0000000..2b8c75a
--- /dev/null
+++ b/shims/crypto/create-hash.js
@@ -0,0 +1,60 @@
+// Shim for crypto.createHash
+// Obsidian uses createHash('SHA256') for signature verification (main process only)
+// and possibly for content hashing in the renderer.
+// Uses SubtleCrypto where possible.
+
+export function createHash(algorithm) {
+  const alg = algorithm.toUpperCase().replace('-', '');
+  const subtleAlg = alg === 'SHA256' ? 'SHA-256' : alg === 'SHA1' ? 'SHA-1' : alg === 'SHA512' ? 'SHA-512' : alg;
+
+  let inputData = new Uint8Array(0);
+
+  return {
+    update(data) {
+      if (typeof data === 'string') {
+        data = new TextEncoder().encode(data);
+      }
+      // Concatenate
+      const merged = new Uint8Array(inputData.length + data.length);
+      merged.set(inputData);
+      merged.set(data, inputData.length);
+      inputData = merged;
+      return this;
+    },
+
+    // Note: digest is sync in Node but we may need async.
+    // For now provide sync hex/base64 via a simple JS implementation.
+    // TODO: evaluate if any sync call sites exist; if not, make this async.
+    digest(encoding) {
+      // Fallback: simple sync hash (for SHA-256 only)
+      // This is a placeholder  -  swap in a proper sync implementation if needed
+      console.warn('[shim:crypto] createHash.digest  -  using placeholder');
+      const hash = simpleHash(inputData);
+      if (encoding === 'hex') return hash;
+      if (encoding === 'base64') return btoa(hash);
+      return hash;
+    },
+
+    // Async alternative for contexts that can await
+    async digestAsync(encoding) {
+      const hashBuffer = await crypto.subtle.digest(subtleAlg, inputData);
+      const hashArray = new Uint8Array(hashBuffer);
+      if (encoding === 'hex') {
+        return Array.from(hashArray).map(b => b.toString(16).padStart(2, '0')).join('');
+      }
+      if (encoding === 'base64') {
+        return btoa(String.fromCharCode(...hashArray));
+      }
+      return hashArray;
+    },
+  };
+}
+
+// Very basic placeholder hash  -  not cryptographic, just for bootstrapping
+function simpleHash(data) {
+  let hash = 0;
+  for (let i = 0; i < data.length; i++) {
+    hash = ((hash << 5) - hash + data[i]) | 0;
+  }
+  return Math.abs(hash).toString(16).padStart(8, '0');
+}
diff --git a/shims/crypto/index.js b/shims/crypto/index.js
new file mode 100644
index 0000000..08ff284
--- /dev/null
+++ b/shims/crypto/index.js
@@ -0,0 +1,12 @@
+// Crypto shim
+// Obsidian uses: scrypt, randomBytes, createHash
+
+import { randomBytes } from './random-bytes.js';
+import { createHash } from './create-hash.js';
+import { scrypt } from './scrypt.js';
+
+export const cryptoShim = {
+  randomBytes,
+  createHash,
+  scrypt,
+};
diff --git a/shims/crypto/random-bytes.js b/shims/crypto/random-bytes.js
new file mode 100644
index 0000000..87ba782
--- /dev/null
+++ b/shims/crypto/random-bytes.js
@@ -0,0 +1,20 @@
+// Shim for crypto.randomBytes
+// Uses Web Crypto API under the hood
+
+export function randomBytes(size) {
+  const buf = new Uint8Array(size);
+  crypto.getRandomValues(buf);
+
+  // Add Buffer-like convenience methods
+  buf.toString = function(encoding) {
+    if (encoding === 'hex') {
+      return Array.from(this).map(b => b.toString(16).padStart(2, '0')).join('');
+    }
+    if (encoding === 'base64') {
+      return btoa(String.fromCharCode(...this));
+    }
+    return new TextDecoder().decode(this);
+  };
+
+  return buf;
+}
diff --git a/shims/crypto/scrypt.js b/shims/crypto/scrypt.js
new file mode 100644
index 0000000..0eb066f
--- /dev/null
+++ b/shims/crypto/scrypt.js
@@ -0,0 +1,29 @@
+// Shim for crypto.scrypt
+// Delegates to window.scrypt which is already loaded by Obsidian's own scrypt.js
+
+export function scrypt(password, salt, keylen, options, callback) {
+  // Node signature: scrypt(password, salt, keylen, options, callback)
+  // Obsidian's app.js checks for window.require("crypto") and uses it if available,
+  // otherwise falls back to window.scrypt  -  so this shim just delegates to the latter.
+
+  if (typeof options === 'function') {
+    callback = options;
+    options = {};
+  }
+
+  const N = options?.N || 32768;
+  const r = options?.r || 8;
+  const p = options?.p || 1;
+
+  if (window.scrypt && window.scrypt.scrypt) {
+    // Use the browser scrypt library already loaded by Obsidian
+    const pwBytes = typeof password === 'string' ? new TextEncoder().encode(password) : password;
+    const saltBytes = typeof salt === 'string' ? new TextEncoder().encode(salt) : salt;
+
+    window.scrypt.scrypt(pwBytes, saltBytes, N, r, p, keylen)
+      .then((result) => callback(null, new Uint8Array(result)))
+      .catch((err) => callback(err));
+  } else {
+    callback(new Error('scrypt not available'));
+  }
+}
diff --git a/shims/path.js b/shims/path.js
new file mode 100644
index 0000000..fac79d0
--- /dev/null
+++ b/shims/path.js
@@ -0,0 +1,6 @@
+// Path shim  -  delegates to path-browserify (bundled via esbuild alias)
+// Configured for posix mode since vault paths are normalized to forward slashes.
+
+import pathBrowserify from 'path';
+
+export const pathShim = pathBrowserify;
diff --git a/shims/url.js b/shims/url.js
new file mode 100644
index 0000000..9bc0d34
--- /dev/null
+++ b/shims/url.js
@@ -0,0 +1,24 @@
+// URL shim
+// Obsidian uses: pathToFileURL, fileURLToPath, URL, URLSearchParams
+
+export const urlShim = {
+  URL: globalThis.URL,
+  URLSearchParams: globalThis.URLSearchParams,
+
+  pathToFileURL(p) {
+    // Return an object with .href matching Node's url.pathToFileURL behavior
+    const encoded = encodeURI(p.replace(/\\/g, '/'));
+    const href = 'file:///' + encoded.replace(/^\/+/, '');
+    return { href, toString: () => href };
+  },
+
+  fileURLToPath(url) {
+    let str = typeof url === 'string' ? url : url.href || url.toString();
+    if (str.startsWith('file:///')) {
+      str = str.slice(8);
+    } else if (str.startsWith('file://')) {
+      str = str.slice(7);
+    }
+    return decodeURI(str);
+  },
+};