diff --git a/packages/opvault.js/adapters/browser.ts b/packages/opvault.js/adapters/browser.ts
new file mode 100644
index 0000000..e38f70f
--- /dev/null
+++ b/packages/opvault.js/adapters/browser.ts
@@ -0,0 +1,124 @@
+import { Buffer } from "buffer"
+import createHmac from "create-hmac"
+import type { IAdapter, IFileSystem } from "./index"
+
+function normalize(path: string) {
+  return path.replace(/^\//, "")
+}
+
+function splitPath(path: string) {
+  const segments = normalize(path).split("/")
+  const filename = segments.pop()!
+  return [segments, filename] as const
+}
+
+export class FileSystem implements IFileSystem {
+  constructor(private handle: FileSystemDirectoryHandle) {}
+
+  static async create() {
+    const handle = await showDirectoryPicker()
+    return new FileSystem(handle)
+  }
+
+  private async getDirectoryHandle(segments: string[]) {
+    if (!segments.length || (segments.length === 1 && !segments[0])) {
+      return this.handle
+    }
+    const [first, ...pathSegments] = segments
+    const handle = await pathSegments.reduce(
+      async (accum, next) => (await accum).getDirectoryHandle(next),
+      this.handle.getDirectoryHandle(first)
+    )
+    return handle
+  }
+
+  private async getFileHandle(path: string) {
+    const [segments, filename] = splitPath(path)
+    const dirHandle = await this.getDirectoryHandle(segments)
+    const fileHandle = await dirHandle.getFileHandle(filename)
+    return fileHandle
+  }
+
+  async readFile(path: string) {
+    const handle = await this.getFileHandle(path)
+    const file = await handle.getFile()
+    return file.text()
+  }
+
+  async exists(path: string): Promise<boolean> {
+    if (path === "/") {
+      return true
+    }
+
+    const [segments, filename] = splitPath(path)
+    let { handle } = this
+    for (const segment of segments) {
+      try {
+        handle = await handle.getDirectoryHandle(segment)
+      } catch {
+        return false
+      }
+    }
+
+    return (
+      (await success(() => handle.getFileHandle(filename))) ||
+      (await success(() => handle.getDirectoryHandle(filename)))
+    )
+  }
+
+  async readBuffer(path: string): Promise<Buffer> {
+    const handle = await this.getFileHandle(path)
+    const file = await handle.getFile()
+    return Buffer.from(await file.arrayBuffer())
+  }
+
+  async writeFile(path: string, data: string): Promise<void> {
+    const handle = await this.getFileHandle(path)
+    const writable = await handle.createWritable()
+    await writable.write(data)
+    await writable.close()
+  }
+
+  async readdir(path: string): Promise<string[]> {
+    const segments = normalize(path).split("/")
+    const dirHandle = await this.getDirectoryHandle(segments)
+    const keys: string[] = []
+    for await (const key of dirHandle.keys()) {
+      keys.push(key)
+    }
+    return keys
+  }
+
+  async isDirectory(path: string) {
+    const [segments, filename] = splitPath(path)
+    const dirHandle = await this.getDirectoryHandle(segments)
+    for await (const [key, handle] of dirHandle.entries()) {
+      if (key !== filename) continue
+
+      if (handle instanceof FileSystemDirectoryHandle) {
+        return true
+      } else {
+        return false
+      }
+    }
+    return false
+  }
+}
+
+async function success(fn: () => Promise<any>) {
+  try {
+    await fn()
+    return true
+  } catch {
+    return false
+  }
+}
+
+/**
+ * Default Browser adapter.
+ */
+export const getBrowserAdapter = (handle: FileSystemDirectoryHandle): IAdapter => ({
+  fs: new FileSystem(handle),
+  subtle: crypto.subtle,
+  hmacSHA256: (key, data) => createHmac("sha256", key).update(data).digest(),
+})
diff --git a/packages/opvault.js/adapters/decipher.ts b/packages/opvault.js/adapters/decipher.ts
new file mode 100644
index 0000000..422edd6
--- /dev/null
+++ b/packages/opvault.js/adapters/decipher.ts
@@ -0,0 +1,324 @@
+function bufferXor(a: Buffer, b: Buffer) {
+  const length = Math.min(a.length, b.length)
+  const buffer = Buffer.alloc(length)
+
+  for (let i = 0; i < length; ++i) {
+    buffer[i] = a[i] ^ b[i]
+  }
+
+  return buffer
+}
+
+function asUInt32Array(buf: Buffer) {
+  const len = (buf.length / 4) | 0
+  const out: number[] = new Array(len)
+
+  for (let i = 0; i < len; i++) {
+    out[i] = buf.readUInt32BE(i * 4)
+  }
+
+  return out
+}
+
+function cryptBlock(
+  M: number[],
+  keySchedule: number[],
+  SUB_MIX: number[][],
+  SBOX: number[],
+  nRounds: number
+) {
+  const SUB_MIX0 = SUB_MIX[0]
+  const SUB_MIX1 = SUB_MIX[1]
+  const SUB_MIX2 = SUB_MIX[2]
+  const SUB_MIX3 = SUB_MIX[3]
+
+  let s0 = M[0] ^ keySchedule[0]
+  let s1 = M[1] ^ keySchedule[1]
+  let s2 = M[2] ^ keySchedule[2]
+  let s3 = M[3] ^ keySchedule[3]
+  let t0: number
+  let t1: number
+  let t2: number
+  let t3: number
+  let ksRow = 4
+
+  for (let round = 1; round < nRounds; round++) {
+    t0 =
+      SUB_MIX0[s0 >>> 24] ^
+      SUB_MIX1[(s1 >>> 16) & 0xff] ^
+      SUB_MIX2[(s2 >>> 8) & 0xff] ^
+      SUB_MIX3[s3 & 0xff] ^
+      keySchedule[ksRow++]
+    t1 =
+      SUB_MIX0[s1 >>> 24] ^
+      SUB_MIX1[(s2 >>> 16) & 0xff] ^
+      SUB_MIX2[(s3 >>> 8) & 0xff] ^
+      SUB_MIX3[s0 & 0xff] ^
+      keySchedule[ksRow++]
+    t2 =
+      SUB_MIX0[s2 >>> 24] ^
+      SUB_MIX1[(s3 >>> 16) & 0xff] ^
+      SUB_MIX2[(s0 >>> 8) & 0xff] ^
+      SUB_MIX3[s1 & 0xff] ^
+      keySchedule[ksRow++]
+    t3 =
+      SUB_MIX0[s3 >>> 24] ^
+      SUB_MIX1[(s0 >>> 16) & 0xff] ^
+      SUB_MIX2[(s1 >>> 8) & 0xff] ^
+      SUB_MIX3[s2 & 0xff] ^
+      keySchedule[ksRow++]
+    s0 = t0
+    s1 = t1
+    s2 = t2
+    s3 = t3
+  }
+
+  t0 =
+    ((SBOX[s0 >>> 24] << 24) |
+      (SBOX[(s1 >>> 16) & 0xff] << 16) |
+      (SBOX[(s2 >>> 8) & 0xff] << 8) |
+      SBOX[s3 & 0xff]) ^
+    keySchedule[ksRow++]
+  t1 =
+    ((SBOX[s1 >>> 24] << 24) |
+      (SBOX[(s2 >>> 16) & 0xff] << 16) |
+      (SBOX[(s3 >>> 8) & 0xff] << 8) |
+      SBOX[s0 & 0xff]) ^
+    keySchedule[ksRow++]
+  t2 =
+    ((SBOX[s2 >>> 24] << 24) |
+      (SBOX[(s3 >>> 16) & 0xff] << 16) |
+      (SBOX[(s0 >>> 8) & 0xff] << 8) |
+      SBOX[s1 & 0xff]) ^
+    keySchedule[ksRow++]
+  t3 =
+    ((SBOX[s3 >>> 24] << 24) |
+      (SBOX[(s0 >>> 16) & 0xff] << 16) |
+      (SBOX[(s1 >>> 8) & 0xff] << 8) |
+      SBOX[s2 & 0xff]) ^
+    keySchedule[ksRow++]
+  t0 = t0 >>> 0
+  t1 = t1 >>> 0
+  t2 = t2 >>> 0
+  t3 = t3 >>> 0
+
+  return [t0, t1, t2, t3]
+}
+
+// AES constants
+const RCON = [0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36]
+const G = (function () {
+  // Compute double table
+  const d = new Array(256)
+  for (let j = 0; j < 256; j++) {
+    if (j < 128) {
+      d[j] = j << 1
+    } else {
+      d[j] = (j << 1) ^ 0x11b
+    }
+  }
+
+  const SBOX: number[] = []
+  const INV_SBOX: number[] = []
+  const SUB_MIX: number[][] = [[], [], [], []]
+  const INV_SUB_MIX: number[][] = [[], [], [], []]
+
+  // Walk GF(2^8)
+  let x = 0
+  let xi = 0
+  for (let i = 0; i < 256; ++i) {
+    // Compute sbox
+    let sx = xi ^ (xi << 1) ^ (xi << 2) ^ (xi << 3) ^ (xi << 4)
+    sx = (sx >>> 8) ^ (sx & 0xff) ^ 0x63
+    SBOX[x] = sx
+    INV_SBOX[sx] = x
+
+    // Compute multiplication
+    const x2 = d[x]
+    const x4 = d[x2]
+    const x8 = d[x4]
+
+    // Compute sub bytes, mix columns tables
+    let t = (d[sx] * 0x101) ^ (sx * 0x1010100)
+    SUB_MIX[0][x] = (t << 24) | (t >>> 8)
+    SUB_MIX[1][x] = (t << 16) | (t >>> 16)
+    SUB_MIX[2][x] = (t << 8) | (t >>> 24)
+    SUB_MIX[3][x] = t
+
+    // Compute inv sub bytes, inv mix columns tables
+    t = (x8 * 0x1010101) ^ (x4 * 0x10001) ^ (x2 * 0x101) ^ (x * 0x1010100)
+    INV_SUB_MIX[0][sx] = (t << 24) | (t >>> 8)
+    INV_SUB_MIX[1][sx] = (t << 16) | (t >>> 16)
+    INV_SUB_MIX[2][sx] = (t << 8) | (t >>> 24)
+    INV_SUB_MIX[3][sx] = t
+
+    if (x === 0) {
+      x = xi = 1
+    } else {
+      x = x2 ^ d[d[d[x8 ^ x2]]]
+      xi ^= d[d[xi]]
+    }
+  }
+
+  return {
+    SBOX,
+    INV_SBOX,
+    SUB_MIX,
+    INV_SUB_MIX,
+  }
+})()
+
+class AES {
+  private _key: number[]
+  private _nRounds!: number
+  private _invKeySchedule!: number[]
+
+  constructor(key: Buffer) {
+    this._key = asUInt32Array(key)
+    this._reset()
+  }
+
+  _reset() {
+    const keyWords = this._key
+    const keySize = keyWords.length
+    const nRounds = keySize + 6
+    const ksRows = (nRounds + 1) * 4
+
+    const keySchedule: number[] = []
+    for (let k = 0; k < keySize; k++) {
+      keySchedule[k] = keyWords[k]
+    }
+
+    for (let k = keySize; k < ksRows; k++) {
+      let t = keySchedule[k - 1]
+
+      if (k % keySize === 0) {
+        t = (t << 8) | (t >>> 24)
+        t =
+          (G.SBOX[t >>> 24] << 24) |
+          (G.SBOX[(t >>> 16) & 0xff] << 16) |
+          (G.SBOX[(t >>> 8) & 0xff] << 8) |
+          G.SBOX[t & 0xff]
+
+        t ^= RCON[(k / keySize) | 0] << 24
+      } else if (keySize > 6 && k % keySize === 4) {
+        t =
+          (G.SBOX[t >>> 24] << 24) |
+          (G.SBOX[(t >>> 16) & 0xff] << 16) |
+          (G.SBOX[(t >>> 8) & 0xff] << 8) |
+          G.SBOX[t & 0xff]
+      }
+
+      keySchedule[k] = keySchedule[k - keySize] ^ t
+    }
+
+    const invKeySchedule = []
+    for (let ik = 0; ik < ksRows; ik++) {
+      const ksR = ksRows - ik
+      const tt = keySchedule[ksR - (ik % 4 ? 0 : 4)]
+
+      if (ik < 4 || ksR <= 4) {
+        invKeySchedule[ik] = tt
+      } else {
+        invKeySchedule[ik] =
+          G.INV_SUB_MIX[0][G.SBOX[tt >>> 24]] ^
+          G.INV_SUB_MIX[1][G.SBOX[(tt >>> 16) & 0xff]] ^
+          G.INV_SUB_MIX[2][G.SBOX[(tt >>> 8) & 0xff]] ^
+          G.INV_SUB_MIX[3][G.SBOX[tt & 0xff]]
+      }
+    }
+
+    this._nRounds = nRounds
+    this._invKeySchedule = invKeySchedule
+  }
+
+  decryptBlock(buffer: Buffer) {
+    const M = asUInt32Array(buffer)
+
+    // swap
+    const m1 = M[1]
+    M[1] = M[3]
+    M[3] = m1
+
+    const out = cryptBlock(
+      M,
+      this._invKeySchedule,
+      G.INV_SUB_MIX,
+      G.INV_SBOX,
+      this._nRounds
+    )
+
+    const buf = Buffer.allocUnsafe(16)
+    buf.writeUInt32BE(out[0], 0)
+    buf.writeUInt32BE(out[3], 4)
+    buf.writeUInt32BE(out[2], 8)
+    buf.writeUInt32BE(out[1], 12)
+    return buf
+  }
+
+  static blockSize = 4 * 4
+  static keySize = 256 / 8
+}
+
+class Decipher {
+  private _cipher: AES
+  private _prev: Buffer
+  private _cache = new Splitter()
+
+  constructor(key: Buffer, iv: Buffer) {
+    this._cipher = new AES(key)
+    this._prev = Buffer.from(iv)
+  }
+
+  update(data: Buffer) {
+    this._cache.add(data)
+    let chunk: Buffer | null
+    let thing: Buffer
+    const out: Buffer[] = []
+    while ((chunk = this._cache.get())) {
+      thing = this.cbc_decrypt(chunk)
+      out.push(thing)
+    }
+    return Buffer.concat(out)
+  }
+
+  setAutoPadding(setTo: boolean) {
+    return this
+  }
+
+  cbc_decrypt(block: Buffer) {
+    const pad = this._prev
+
+    this._prev = block
+    const out = this._cipher.decryptBlock(block)
+
+    return bufferXor(out, pad)
+  }
+}
+
+class Splitter {
+  cache = Buffer.allocUnsafe(0)
+
+  add(data: Buffer) {
+    this.cache = Buffer.concat([this.cache, data])
+  }
+
+  get() {
+    if (this.cache.length >= 16) {
+      const out = this.cache.slice(0, 16)
+      this.cache = this.cache.slice(16)
+      return out
+    }
+    return null
+  }
+}
+
+export function createDecipheriv(_suite: any, password: Buffer, iv: Buffer) {
+  if (iv.length !== 16) {
+    throw new TypeError(`invalid iv length ${iv.length}`)
+  }
+  if (password.length !== 256 / 8) {
+    throw new TypeError(`invalid key length ${password.length}`)
+  }
+  return new Decipher(password, iv)
+}
diff --git a/src/adapters/index.d.ts b/packages/opvault.js/adapters/index.d.ts
similarity index 64%
rename from src/adapters/index.d.ts
rename to packages/opvault.js/adapters/index.d.ts
index 90f2a4d..eb5eb14 100644
--- a/src/adapters/index.d.ts
+++ b/packages/opvault.js/adapters/index.d.ts
@@ -3,10 +3,10 @@
  */
 export interface IFileSystem {
   /**
-   * Synchronously tests whether or not the given path exists by checking with the file system.
+   * Asynchronously tests whether or not the given path exists by checking with the file system.
    * @param path A path to a file or directory.
    */
-  existsSync(path: string): boolean
+  exists(path: string): Promise<boolean>
 
   /**
    * Asynchronously reads the entire contents of a file.
@@ -34,10 +34,9 @@ export interface IFileSystem {
   readdir(path: string): Promise<string[]>
 
   /**
-   * Asynchronous stat(2) - Get file status.
-   * @param path A path to a file.
+   * Returns true if the path points to a directory.
    */
-  stat(path: string): Promise<{ isDirectory(): boolean }>
+  isDirectory(path: string): Promise<boolean>
 }
 
 export interface IAdapter {
@@ -46,4 +45,16 @@ export interface IAdapter {
    * `memfs` or any object that implements `IFileSystem`.
    */
   fs: IFileSystem
+
+  /**
+   * `SubtleCrypto` implementation. On Node.js this is
+   * `require("crypto").webcrypto.subtle` and in the browser this is
+   * `window.crypto.subtle`.
+   */
+  subtle: SubtleCrypto
+
+  /**
+   * Equivalent to `createHmac("sha256", key).update(data).digest()`
+   */
+  hmacSHA256(key: Buffer, data: Buffer): Buffer
 }
diff --git a/src/adapters/node.ts b/packages/opvault.js/adapters/node.ts
similarity index 53%
rename from src/adapters/node.ts
rename to packages/opvault.js/adapters/node.ts
index 618a386..428afdd 100644
--- a/src/adapters/node.ts
+++ b/packages/opvault.js/adapters/node.ts
@@ -1,4 +1,5 @@
 import { promises as fs, existsSync } from "fs"
+import { webcrypto, createHmac } from "crypto"
 
 import type { IAdapter } from "./index"
 
@@ -6,15 +7,15 @@ import type { IAdapter } from "./index"
  * Default Node.js adapter. This can be used while using `opvault.js`
  * in a Node.js environment.
  */
-const nodeAdapter: IAdapter = {
+export const adapter: IAdapter = {
   fs: {
     readFile: path => fs.readFile(path, "utf-8"),
     readBuffer: path => fs.readFile(path),
     writeFile: fs.writeFile,
     readdir: fs.readdir,
-    stat: fs.stat,
-    existsSync,
+    isDirectory: async path => fs.stat(path).then(x => x.isDirectory()),
+    exists: async path => existsSync(path),
   },
+  subtle: (webcrypto as any).subtle,
+  hmacSHA256: (key, data) => createHmac("sha256", key).update(data).digest(),
 }
-
-export default nodeAdapter
diff --git a/packages/opvault.js/ee.ts b/packages/opvault.js/ee.ts
new file mode 100644
index 0000000..c5a8cba
--- /dev/null
+++ b/packages/opvault.js/ee.ts
@@ -0,0 +1,22 @@
+export function createEventEmitter<T = void>() {
+  type EventListener = T extends void ? () => void : (value: T) => void
+  type Emitter = T extends void
+    ? { (): void; (listener: EventListener): IDisposable }
+    : { (value: T): void; (listener: EventListener): IDisposable }
+
+  const listeners = new Set<EventListener>()
+
+  function emitter(value: T | EventListener) {
+    if (typeof value === "function") {
+      listeners.add(value as EventListener)
+      return {
+        dispose() {
+          listeners.delete(value as EventListener)
+        },
+      }
+    } else {
+      listeners.forEach(fn => fn(value))
+    }
+  }
+  return emitter as Emitter
+}
diff --git a/src/errors.ts b/packages/opvault.js/errors.ts
similarity index 100%
rename from src/errors.ts
rename to packages/opvault.js/errors.ts
diff --git a/src/fs.ts b/packages/opvault.js/fs.ts
similarity index 87%
rename from src/fs.ts
rename to packages/opvault.js/fs.ts
index ef9288b..7e7320d 100644
--- a/src/fs.ts
+++ b/packages/opvault.js/fs.ts
@@ -5,14 +5,14 @@ import { once } from "./util"
 
 export type OnePasswordFileManager = ReturnType<typeof OnePasswordFileManager>
 
-export function OnePasswordFileManager(
+export async function OnePasswordFileManager(
   fs: IFileSystem,
   path: string,
   profileName: string
 ) {
   const root = resolve(path, profileName)
-  invariant(fs.existsSync(path), `Path ${path} does not exist.`)
-  invariant(fs.existsSync(root), `Profile ${profileName} does not exist.`)
+  invariant(await fs.exists(path), `Path ${path} does not exist.`)
+  invariant(await fs.exists(root), `Profile ${profileName} does not exist.`)
 
   const abs = (path: string) => resolve(root, path)
 
@@ -46,7 +46,7 @@ export function OnePasswordFileManager(
 
     async getBand(name: string) {
       const path = abs(`band_${name}.js`)
-      if (fs.existsSync(path)) {
+      if (await fs.exists(path)) {
         return await fs.readFile(path)
       }
     },
diff --git a/src/global.d.ts b/packages/opvault.js/global.d.ts
similarity index 100%
rename from src/global.d.ts
rename to packages/opvault.js/global.d.ts
diff --git a/src/i18n/index.ts b/packages/opvault.js/i18n/index.ts
similarity index 100%
rename from src/i18n/index.ts
rename to packages/opvault.js/i18n/index.ts
diff --git a/src/i18n/res.json b/packages/opvault.js/i18n/res.json
similarity index 100%
rename from src/i18n/res.json
rename to packages/opvault.js/i18n/res.json
diff --git a/src/index.ts b/packages/opvault.js/index.ts
similarity index 80%
rename from src/index.ts
rename to packages/opvault.js/index.ts
index c376d58..2b2dbf4 100644
--- a/src/index.ts
+++ b/packages/opvault.js/index.ts
@@ -1,6 +1,5 @@
 import { resolve } from "path"
 import { Vault } from "./models/vault"
-import { invariant } from "./errors"
 import type { IAdapter } from "./adapters"
 import { asyncMap } from "./util"
 
@@ -26,10 +25,9 @@ export class OnePassword {
   readonly #path: string
   readonly #adapter: IAdapter
 
-  constructor({ path, adapter = require("./adapters/node").default }: IOptions) {
+  constructor({ path, adapter = require("./adapters/node").adapter }: IOptions) {
     this.#adapter = adapter
     this.#path = path
-    invariant(path, "Path must not be empty")
   }
 
   /**
@@ -41,8 +39,10 @@ export class OnePassword {
     const profiles: string[] = []
     await asyncMap(children, async child => {
       const fullPath = resolve(path, child)
-      const stats = await fs.stat(fullPath)
-      if (stats.isDirectory() && fs.existsSync(resolve(fullPath, "profile.js"))) {
+      if (
+        (await fs.isDirectory(fullPath)) &&
+        (await fs.exists(resolve(fullPath, "profile.js")))
+      ) {
         profiles.push(child)
       }
     })
diff --git a/src/models.ts b/packages/opvault.js/models.ts
similarity index 100%
rename from src/models.ts
rename to packages/opvault.js/models.ts
diff --git a/src/models/attachment.ts b/packages/opvault.js/models/attachment.ts
similarity index 83%
rename from src/models/attachment.ts
rename to packages/opvault.js/models/attachment.ts
index 21478de..4e5916c 100644
--- a/src/models/attachment.ts
+++ b/packages/opvault.js/models/attachment.ts
@@ -1,5 +1,5 @@
+import { Buffer } from "buffer"
 import type { Crypto } from "./crypto"
-import { decryptOPData } from "./crypto"
 import { invariant } from "../errors"
 
 type integer = number
@@ -38,7 +38,7 @@ export class Attachment {
     this.metadataSize = buffer.readIntLE(8, 2)
     this.iconSize = buffer.readIntLE(12, 3)
 
-    crypto.on("lock", () => {
+    crypto.onLock(() => {
       this.#lock()
     })
   }
@@ -80,18 +80,21 @@ export class Attachment {
   }
 
   #decrypt() {
-    const cipher = this.#crypto.deriveConcreteKey({ k: this.#k })
+    const crypto = this.#crypto
+    const cipher = crypto.deriveConcreteKey({ k: this.#k })
     const { metadataSize, iconSize } = this
     const buffer = this.#buffer
-    this.#icon = decryptOPData(
+    this.#icon = crypto.decryptOPData(
       buffer.slice(16 + metadataSize, 16 + metadataSize + iconSize),
       cipher
     )
-    this.#file = decryptOPData(buffer.slice(16 + metadataSize + iconSize), cipher)
+    this.#file = crypto.decryptOPData(buffer.slice(16 + metadataSize + iconSize), cipher)
 
     const metadata = JSON.parse(buffer.slice(16, 16 + metadataSize).toString("utf-8"))
     metadata.overview = JSON.parse(
-      decryptOPData(Buffer.from(metadata.overview, "base64"), this.#crypto.ov).toString()
+      crypto
+        .decryptOPData(Buffer.from(metadata.overview, "base64"), crypto.overview)
+        .toString()
     )
     this.#metadata = metadata
   }
diff --git a/packages/opvault.js/models/crypto.ts b/packages/opvault.js/models/crypto.ts
new file mode 100644
index 0000000..da7cede
--- /dev/null
+++ b/packages/opvault.js/models/crypto.ts
@@ -0,0 +1,173 @@
+import { Buffer } from "buffer"
+import { createDecipheriv } from "../adapters/decipher"
+import type { IAdapter } from "../adapters"
+import { createEventEmitter } from "../ee"
+import { HMACAssertionError } from "../errors"
+import type { i18n } from "../i18n"
+import type { ItemDetails, Overview, Profile } from "../types"
+import { setIfAbsent } from "../util"
+import type { EncryptedItem } from "./item"
+
+/** Encryption and MAC */
+export interface Cipher {
+  /** Encryption key */
+  key: Buffer
+  /** HMAC key */
+  hmac: Buffer
+}
+
+export class Crypto implements IDisposable {
+  #disposables: IDisposable[] = []
+  #locked = true
+
+  #master!: Cipher
+  #overview!: Cipher
+
+  private subtle: SubtleCrypto
+  private hmacSHA256: IAdapter["hmacSHA256"]
+
+  readonly onLock = createEventEmitter<void>()
+
+  constructor(private readonly i18n: i18n, adapter: IAdapter) {
+    this.subtle = adapter.subtle
+    this.hmacSHA256 = adapter.hmacSHA256
+  }
+
+  async unlock(profile: Profile, masterPassword: string) {
+    const encoder = new TextEncoder()
+    const key = await this.subtle.importKey(
+      "raw",
+      encoder.encode(masterPassword),
+      { name: "PBKDF2" },
+      false,
+      ["deriveBits"]
+    )
+    const derivedKey = await this.subtle.deriveBits(
+      {
+        name: "PBKDF2",
+        salt: Buffer.from(profile.salt, "base64"),
+        iterations: profile.iterations,
+        hash: {
+          name: "SHA-512",
+        },
+      },
+      key,
+      64 << 3
+    )
+
+    const cipher = splitPlainText(Buffer.from(derivedKey))
+
+    // Derive master key and overview keys
+    this.#master = await this.decryptKeys(profile.masterKey, cipher)
+    this.#overview = await this.decryptKeys(profile.overviewKey, cipher)
+    this.#locked = false
+  }
+
+  get locked() {
+    return this.#locked
+  }
+
+  lock() {
+    this.#locked = true
+    this.#master = null!
+    this.#overview = null!
+    this.#disposables.forEach(fn => fn.dispose())
+    this.onLock()
+  }
+
+  dispose() {
+    this.lock()
+  }
+
+  assertUnlocked() {
+    if (this.#locked) {
+      throw new Error(this.i18n.error.vaultIsLocked)
+    }
+  }
+
+  #createCache = <K, V, K2 = K>(
+    deriveArg: (value: K) => K2,
+    implementation: (value: K2) => V
+  ) => {
+    const map = new Map<K2, V>()
+    this.#disposables.push({
+      dispose: () => map.clear(),
+    })
+    return (data: K) => setIfAbsent(map, deriveArg(data), implementation)
+  }
+
+  #createWeakCache = <K extends object, V>(implementation: (value: K) => V) => {
+    let map = new WeakMap<K, V>()
+    this.#disposables.push({
+      dispose() {
+        map = new WeakMap()
+      },
+    })
+    return (data: K) => setIfAbsent(map, data, implementation)
+  }
+
+  decryptItemDetails = this.#createWeakCache((item: EncryptedItem) => {
+    const cipher = this.deriveConcreteKey(item)
+    const detail = this.decryptOPData(Buffer.from(item.d, "base64"), cipher)
+    return JSON.parse(detail.toString("utf-8")) as ItemDetails
+  })
+
+  decryptItemOverview = this.#createCache(
+    (item: EncryptedItem) => item.o,
+    (o: string) => {
+      const overview = this.decryptOPData(Buffer.from(o, "base64"), this.#overview)
+      return JSON.parse(overview.toString("utf8")) as Overview
+    }
+  )
+
+  deriveConcreteKey = this.#createCache(
+    (data: { k: string }) => data.k,
+    ($k: string) => {
+      const k = Buffer.from($k, "base64")
+      const data = k.slice(0, -32)
+      this.assertHMac(data, this.#master.hmac, k.slice(-32))
+      const derivedKey = decryptData(this.#master.key, data.slice(0, 16), data.slice(16))
+      return splitPlainText(derivedKey)
+    }
+  )
+
+  assertHMac(data: Buffer, key: Buffer, expected: Buffer) {
+    const actual = this.hmacSHA256(key, data)
+    if (!actual.equals(expected)) {
+      throw new HMACAssertionError()
+    }
+  }
+
+  decryptOPData(cipherText: Buffer, cipher: Cipher) {
+    const key = cipherText.slice(0, -32)
+    this.assertHMac(key, cipher.hmac, cipherText.slice(-32))
+
+    const plaintext = decryptData(cipher.key, key.slice(16, 32), key.slice(32))
+    const size = readUint16(key.slice(8, 16))
+    return plaintext.slice(-size)
+  }
+
+  async decryptKeys(encryptedKey: string, derived: Cipher) {
+    const buffer = Buffer.from(encryptedKey, "base64")
+    const base = this.decryptOPData(buffer, derived)
+    const digest = await this.subtle.digest("SHA-512", base)
+    return splitPlainText(Buffer.from(digest))
+  }
+
+  get overview() {
+    return this.#overview
+  }
+}
+
+export const splitPlainText = (derivedKey: Buffer): Cipher => ({
+  key: derivedKey.slice(0, 32),
+  hmac: derivedKey.slice(32, 64),
+})
+
+function decryptData(key: Buffer, iv: Buffer, data: Buffer) {
+  return createDecipheriv("aes-256-cbc", key, iv).setAutoPadding(false).update(data)
+}
+
+function readUint16({ buffer, byteOffset, length }: Buffer) {
+  return new DataView(buffer, byteOffset, length).getUint16(0, true)
+}
diff --git a/src/models/item.ts b/packages/opvault.js/models/item.ts
similarity index 100%
rename from src/models/item.ts
rename to packages/opvault.js/models/item.ts
diff --git a/src/models/vault.ts b/packages/opvault.js/models/vault.ts
similarity index 69%
rename from src/models/vault.ts
rename to packages/opvault.js/models/vault.ts
index 0e6dac0..92d3ae0 100644
--- a/src/models/vault.ts
+++ b/packages/opvault.js/models/vault.ts
@@ -5,41 +5,33 @@ import { i18n } from "../i18n"
 import type { EncryptedItem } from "./item"
 import { Crypto } from "./crypto"
 import { Item } from "./item"
-import type { Profile, Overview } from "../types"
+import type { Profile } from "../types"
 import { WeakValueMap } from "../weakMap"
-import { EventEmitter } from "../ee"
-import { asyncMap } from "../util"
+import { createEventEmitter } from "../ee"
 
-type Band = { [uuid: string]: Item }
-type FoldersMap = { [uuid: string]: Band }
-
-interface VaultEvents {
-  lock: void
-}
+// type FoldersMap = { [uuid: string]: { [uuid: string]: Item } }
 
 /**
  * Main OnePassword Vault class
  */
-export class Vault extends EventEmitter<VaultEvents> {
-  // File system interface
+export class Vault {
   #profile: Profile
-  #folders: FoldersMap
-
+  // #folders: FoldersMap
   #items: Item[] = []
   #itemsMap = new WeakValueMap<string, Item>()
-
   #crypto: Crypto
 
+  readonly onLock = createEventEmitter<void>()
+
   private constructor(
     profile: Profile,
-    folders: FoldersMap,
+    // folders: FoldersMap,
     items: Item[],
     crypto: Crypto,
     itemsMap: WeakValueMap<string, Item>
   ) {
-    super()
     this.#profile = profile
-    this.#folders = folders
+    // this.#folders = folders
     this.#items = items
     this.#crypto = crypto
     this.#itemsMap = itemsMap
@@ -50,12 +42,12 @@ export class Vault extends EventEmitter<VaultEvents> {
    * @internal
    */
   static async of(path: string, profileName = "default", adapter: IAdapter) {
-    const crypto = new Crypto(i18n)
-    const files = OnePasswordFileManager(adapter.fs, path, profileName)
+    const crypto = new Crypto(i18n, adapter)
+    const files = await OnePasswordFileManager(adapter.fs, path, profileName)
     const profile = JSON.parse(
       stripText(await files.getProfile(), /^var profile\s*=/, ";")
     )
-    const folders = JSON.parse(stripText(await files.getFolders(), "loadFolders(", ");"))
+    // const folders = JSON.parse(stripText(await files.getFolders(), "loadFolders(", ");"))
 
     const itemsMap = new WeakValueMap<string, Item>()
     const bands: Item[] = []
@@ -75,34 +67,23 @@ export class Vault extends EventEmitter<VaultEvents> {
     }
 
     const attachments = await files.getAttachments()
-    await asyncMap(attachments, async att => {
+    for (const att of attachments) {
       const file = itemsMap.get(att.itemUUID)
       invariant(file, `Item ${att.itemUUID} of attachment does not exist`)
       file.addAttachment(await att.getFile())
-    })
+    }
 
-    return new Vault(profile, folders, bands, crypto, itemsMap)
+    return new Vault(profile, bands, crypto, itemsMap)
   }
 
-  readonly overviews = Object.freeze({
-    get: (condition: string | ((overview: Overview) => boolean)) => {
-      this.#crypto.assertUnlocked()
-      if (typeof condition === "string") {
-        const title = condition
-        condition = overview => overview.title === title
-      }
-      for (const value of this.#items) {
-        if (condition(value.overview)) {
-          return value
-        }
-      }
-    },
+  getOverview(uuid: string) {
+    this.#crypto.assertUnlocked()
+    return this.#items.find(x => x.uuid === uuid)?.overview
+  }
 
-    values: () => {
-      this.#crypto.assertUnlocked()
-      return Array.from(this.#items.map(x => x.overview))
-    },
-  })
+  keys() {
+    return this.#items.map(x => x.uuid)
+  }
 
   /**
    * Unlock this OnePassword vault.
@@ -111,7 +92,7 @@ export class Vault extends EventEmitter<VaultEvents> {
    */
   async unlock(masterPassword: string) {
     try {
-      this.#crypto.unlock(this.#profile, masterPassword)
+      await this.#crypto.unlock(this.#profile, masterPassword)
     } catch (e) {
       if (e instanceof HMACAssertionError) {
         throw new Error(i18n.error.invalidPassword)
@@ -126,7 +107,7 @@ export class Vault extends EventEmitter<VaultEvents> {
    */
   lock() {
     this.#crypto.lock()
-    this.emit("lock")
+    this.onLock()
     return this
   }
 
@@ -134,9 +115,20 @@ export class Vault extends EventEmitter<VaultEvents> {
     return this.#crypto.locked
   }
 
-  getItem(uuid: string) {
+  getItem(uuid: string): Item | undefined
+  getItem(filter: { title: string }): Item | undefined
+
+  getItem(filter: any) {
     this.#crypto.assertUnlocked()
-    return this.#itemsMap.get(uuid)
+    if (typeof filter === "string") {
+      return this.#itemsMap.get(filter)
+    } else {
+      for (const value of this.#items) {
+        if (value.overview.title === filter.title) {
+          return value
+        }
+      }
+    }
   }
 }
 
diff --git a/src/types.ts b/packages/opvault.js/types.ts
similarity index 99%
rename from src/types.ts
rename to packages/opvault.js/types.ts
index 632e4a3..00700d1 100644
--- a/src/types.ts
+++ b/packages/opvault.js/types.ts
@@ -151,7 +151,6 @@ export interface Overview {
   url?: string
   tags?: string[]
   URLs?: { u: string }[]
-  uuid?: string // Added manually
   appIds: {
     /** @example 'Firefox' | 'Email' */
     name: string
diff --git a/src/util.ts b/packages/opvault.js/util.ts
similarity index 100%
rename from src/util.ts
rename to packages/opvault.js/util.ts
diff --git a/src/weakMap.ts b/packages/opvault.js/weakMap.ts
similarity index 100%
rename from src/weakMap.ts
rename to packages/opvault.js/weakMap.ts
diff --git a/pnpm-workspace.yaml b/pnpm-workspace.yaml
new file mode 100644
index 0000000..b18b4d0
--- /dev/null
+++ b/pnpm-workspace.yaml
@@ -0,0 +1,2 @@
+packages:
+  - "packages/**/"
diff --git a/src/adapters/browser.ts b/src/adapters/browser.ts
deleted file mode 100644
index 61a04cf..0000000
--- a/src/adapters/browser.ts
+++ /dev/null
@@ -1,89 +0,0 @@
-import { promises as fs, existsSync } from "fs"
-import { Buffer } from "buffer"
-
-import type { IAdapter, IFileSystem } from "./index"
-
-function splitPath(path: string) {
-  const segments = path.split("/")
-  const filename = segments.pop()!
-  return [segments, filename] as const
-}
-
-export class BrowserAdapter implements IFileSystem {
-  constructor(private handle: FileSystemDirectoryHandle) {}
-
-  static async create() {
-    const handle = await showDirectoryPicker()
-    return new BrowserAdapter(handle)
-  }
-
-  private async getDirectoryHandle([first, ...pathSegments]: string[]) {
-    const handle = await pathSegments.reduce(
-      async (accum, next) => (await accum).getDirectoryHandle(next),
-      this.handle.getDirectoryHandle(first)
-    )
-    return handle
-  }
-
-  private async getFileHandle(path: string) {
-    const [segments, filename] = splitPath(path)
-    const dirHandle = await this.getDirectoryHandle(segments)
-    const fileHandle = await dirHandle.getFileHandle(filename)
-    return fileHandle
-  }
-
-  async readFile(path: string) {
-    const handle = await this.getFileHandle(path)
-    const file = await handle.getFile()
-    return file.text()
-  }
-
-  async existsSync(path: string): Promise<boolean> {
-    const [segments, filename] = splitPath(path)
-    let handle = this.handle
-    for (const segment of segments) {
-      handle.values()
-      const next = await handle.getDirectoryHandle()
-    }
-
-    throw new Error("Method not implemented.")
-  }
-
-  async readBuffer(path: string): Promise<Buffer> {
-    const handle = await this.getFileHandle(path)
-    const file = await handle.getFile()
-    return Buffer.from(await file.arrayBuffer())
-  }
-
-  async writeFile(path: string, data: string): Promise<void> {
-    const handle = await this.getFileHandle(path)
-    const writable = await handle.createWritable()
-    await writable.write(data)
-    await writable.close()
-  }
-
-  readdir(path: string): Promise<string[]> {
-    throw new Error("Method not implemented.")
-  }
-
-  stat(path: string): Promise<{ isDirectory(): boolean }> {
-    throw new Error("Method not implemented.")
-  }
-}
-
-/**
- * Default Node.js adapter. This can be used while using `opvault.js`
- * in a Node.js environment.
- */
-const nodeAdapter: IAdapter = {
-  fs: {
-    readFile: path => fs.readFile(path, "utf-8"),
-    readBuffer: path => fs.readFile(path),
-    writeFile: fs.writeFile,
-    readdir: fs.readdir,
-    stat: fs.stat,
-    existsSync,
-  },
-}
-
-export default nodeAdapter
diff --git a/src/ee.ts b/src/ee.ts
deleted file mode 100644
index 95ac4e6..0000000
--- a/src/ee.ts
+++ /dev/null
@@ -1,49 +0,0 @@
-type EventKeyWithNoArg<T> = {
-  [K in keyof T]: T[K] extends void ? K : never
-}[keyof T]
-
-type CallbackSignature<T, K extends keyof T> = K extends EventKeyWithNoArg<T>
-  ? () => void
-  : (value: T[K]) => void
-
-export class EventEmitter<T extends Record</* eventName */ string, /* eventArg */ any>> {
-  #listeners = new Map<keyof T, Set<(...args: any[]) => any>>()
-
-  #getList(key: keyof T) {
-    if (!this.#listeners.has(key)) {
-      this.#listeners.set(key, new Set())
-    }
-    return this.#listeners.get(key)!
-  }
-
-  on<K extends keyof T>(key: K, fn: CallbackSignature<T, K>) {
-    this.#getList(key).add(fn)
-    return this
-  }
-
-  off<K extends keyof T>(key: K, fn: CallbackSignature<T, K>) {
-    this.#getList(key).delete(fn)
-    return this
-  }
-
-  once<K extends keyof T>(key: K, fn: CallbackSignature<T, K>) {
-    const wrapped = (...arg: any[]) => {
-      ;(fn as any)(...arg)
-      this.off(key, wrapped)
-    }
-    return this.on(key, wrapped)
-  }
-
-  emit<K extends EventKeyWithNoArg<T>>(key: K): this
-  emit<K extends keyof T>(key: K, value: T[K]): this
-
-  emit<K extends keyof T>(key: K, value?: T[K]) {
-    const listeners = this.#getList(key)
-    if (arguments.length === 1) {
-      listeners.forEach(fn => fn())
-    } else {
-      listeners.forEach(fn => fn(value!))
-    }
-    return this
-  }
-}
diff --git a/src/models/crypto.ts b/src/models/crypto.ts
deleted file mode 100644
index 71d9121..0000000
--- a/src/models/crypto.ts
+++ /dev/null
@@ -1,179 +0,0 @@
-import * as crypto from "crypto"
-import { createHmac, createDecipheriv, createHash } from "crypto"
-import { EventEmitter } from "../ee"
-import { HMACAssertionError } from "../errors"
-import type { i18n } from "../i18n"
-import type { ItemDetails, Overview, Profile } from "../types"
-import { setIfAbsent } from "../util"
-import type { EncryptedItem } from "./item"
-
-/** Encryption and MAC */
-export interface Cipher {
-  /** Encryption key */
-  key: Buffer
-  /** HMAC key */
-  hmac: Buffer
-}
-
-export class Crypto extends EventEmitter<{ lock: void }> implements IDisposable {
-  #disposables: IDisposable[] = []
-  #locked = true
-
-  #master!: Cipher
-  #overview!: Cipher
-
-  constructor(readonly i18n: i18n) {
-    super()
-  }
-
-  unlock(profile: Profile, masterPassword: string) {
-    const derivedKey = crypto.pbkdf2Sync(
-      masterPassword,
-      Buffer.from(profile.salt, "base64"),
-      profile.iterations,
-      64,
-      "sha512"
-    )
-
-    const cipher = splitPlainText(derivedKey)
-
-    // Derive master key and overview keys
-    this.#master = decryptKeys(profile.masterKey, cipher)
-    this.#overview = decryptKeys(profile.overviewKey, cipher)
-    this.#locked = false
-  }
-
-  get locked() {
-    return this.#locked
-  }
-
-  lock() {
-    this.#locked = true
-    this.#master = null!
-    this.#overview = null!
-    this.#disposables.forEach(fn => fn.dispose())
-    this.emit("lock")
-  }
-
-  dispose() {
-    this.lock()
-  }
-
-  assertUnlocked() {
-    if (this.#locked) {
-      throw new Error(this.i18n.error.vaultIsLocked)
-    }
-  }
-
-  #createCache = <K, V, K2 = K>(
-    deriveArg: (value: K) => K2,
-    implementation: (value: K2) => V
-  ) => {
-    const map = new Map<K2, V>()
-    this.#disposables.push({
-      dispose: () => map.clear(),
-    })
-    return (data: K) => setIfAbsent(map, deriveArg(data), implementation)
-  }
-
-  #createWeakCache = <K extends object, V>(implementation: (value: K) => V) => {
-    let map = new WeakMap<K, V>()
-    this.#disposables.push({
-      dispose() {
-        map = new WeakMap()
-      },
-    })
-    return (data: K) => setIfAbsent(map, data, implementation)
-  }
-
-  decryptItemDetails = this.#createWeakCache((item: EncryptedItem) => {
-    const cipher = this.deriveConcreteKey(item)
-    const detail = decryptOPData(Buffer.from(item.d, "base64"), cipher)
-    return JSON.parse(detail.toString("utf-8")) as ItemDetails
-  })
-
-  decryptItemOverview = this.#createCache(
-    (item: EncryptedItem) => item.o,
-    (o: string) => {
-      const overview = decryptOPData(Buffer.from(o, "base64"), this.#overview)
-      return JSON.parse(overview.toString("utf8")) as Overview
-    }
-  )
-
-  deriveConcreteKey = this.#createCache(
-    (data: { k: string }) => data.k,
-    ($k: string) => {
-      const k = Buffer.from($k, "base64")
-      const data = k.slice(0, -32)
-      assertHMac(data, this.#master.hmac, k.slice(-32))
-      const derivedKey = decryptData(this.#master.key, data.slice(0, 16), data.slice(16))
-      return splitPlainText(derivedKey)
-    }
-  )
-
-  deriveGeneralKey = (input: Buffer) => {}
-
-  get ov() {
-    return this.#overview
-  }
-}
-
-// async function pbkdf2(password: string, salt: string, iterations = 1000, length = 256) {
-//   const encoder = new TextEncoder()
-//   const key = await webcrypto.subtle.importKey(
-//     "raw",
-//     encoder.encode(password),
-//     "PBKDF2",
-//     false,
-//     ["deriveBits"]
-//   )
-//   const bits = await webcrypto.subtle.deriveBits(
-//     {
-//       name: "PBKDF2",
-//       hash: "SHA-512",
-//       salt: encoder.encode(salt),
-//       iterations,
-//     },
-//     key,
-//     length
-//   )
-//   return bits
-// }
-
-export function assertHMac(data: Buffer, key: Buffer, expected: Buffer) {
-  const actual = createHmac("sha256", key).update(data).digest()
-  if (!actual.equals(expected)) {
-    console.error({ actual, expected })
-    throw new HMACAssertionError()
-  }
-}
-
-export const splitPlainText = (derivedKey: Buffer): Cipher => ({
-  key: derivedKey.slice(0, 32),
-  hmac: derivedKey.slice(32, 64),
-})
-
-export function decryptKeys(encryptedKey: string, derived: Cipher) {
-  const buffer = Buffer.from(encryptedKey, "base64")
-  const base = decryptOPData(buffer, derived)
-  const digest = createHash("sha512").update(base).digest()
-  return splitPlainText(digest)
-}
-
-export function decryptData(key: Buffer, iv: Buffer, data: Buffer) {
-  const cipher = createDecipheriv("aes-256-cbc", key, iv).setAutoPadding(false)
-  return Buffer.concat([cipher.update(data), cipher.final()])
-}
-
-export function decryptOPData(cipherText: Buffer, cipher: Cipher) {
-  const key = cipherText.slice(0, -32)
-  assertHMac(key, cipher.hmac, cipherText.slice(-32))
-
-  const plaintext = decryptData(cipher.key, key.slice(16, 32), key.slice(32))
-  const size = readUint16(key.slice(8, 16))
-  return plaintext.slice(-size)
-}
-
-function readUint16({ buffer, byteOffset, length }: Buffer) {
-  return new DataView(buffer, byteOffset, length).getUint16(0, true)
-}