diff --git a/examples/testNode.js b/examples/testNode.js
index 12a92de..dbcf5d7 100644
--- a/examples/testNode.js
+++ b/examples/testNode.js
@@ -21,3 +21,7 @@ const c = Account.add(importKey);
 c.addShard('newShard');
 
 console.log(c.getShardsCount);
+
+c.toFile('123').then((f) => {
+  c.fromFile(f, '123').then(console.log);
+});
diff --git a/package.json b/package.json
index b630696..cf77e07 100644
--- a/package.json
+++ b/package.json
@@ -52,6 +52,7 @@
     "@types/jest": "^23.3.1",
     "@types/jest-json-schema": "^1.2.0",
     "@types/node": "^10.5.6",
+    "@types/pbkdf2": "^3.0.0",
     "@types/uuid": "^3.4.4",
     "@types/valid-url": "^1.0.2",
     "@types/webpack": "^4.4.17",
diff --git a/packages/harmony-account/src/account.ts b/packages/harmony-account/src/account.ts
index 276681c..925835a 100644
--- a/packages/harmony-account/src/account.ts
+++ b/packages/harmony-account/src/account.ts
@@ -3,6 +3,10 @@ import {
   getAddressFromPrivateKey,
   getPubkeyFromPrivateKey,
   toChecksumAddress,
+  encrypt,
+  decrypt,
+  EncryptOptions,
+  Keystore,
 } from '@harmony/crypto';
 
 import { isPrivateKey } from '@harmony/utils';
@@ -49,8 +53,10 @@ class Account {
   }
 
   constructor(key?: string) {
-    if (key === null) {
+    if (!key) {
       this._new();
+    } else {
+      this._import(key);
     }
   }
 
@@ -61,16 +67,46 @@ class Account {
   addShard(id: ShardId): void {
     if (this.shards && this.shards.has('default')) {
       this.shards.set(id, '');
+    } else {
+      throw new Error(
+        'This account has no default shard or shard is not exist',
+      );
+    }
+  }
+
+  async toFile(password: string, options?: EncryptOptions): Promise<string> {
+    if (this.privateKey && isPrivateKey(this.privateKey)) {
+      const file = await encrypt(this.privateKey, password, options);
+      return file;
+    } else {
+      throw new Error('Encryption failed because PrivateKey is not correct');
+    }
+  }
+
+  async fromFile(keyStore: string, password: string): Promise<Account> {
+    try {
+      if (!password) {
+        throw new Error('you must provide password');
+      }
+      const file: Keystore = JSON.parse(keyStore);
+      const decyptedPrivateKey = await decrypt(file, password);
+      if (isPrivateKey(decyptedPrivateKey)) {
+        return Account.add(decyptedPrivateKey);
+      } else {
+        throw new Error('decrypted failed');
+      }
+    } catch (error) {
+      throw error;
     }
-    throw new Error('this account has no default shard or shard is not exist');
   }
 
   /**
    * @function getBalance get Account's balance
    * @return {type} {description}
    */
-  getBalance() {
+  async getBalance(): Promise<string> {
     // console.log()
+    return '';
   }
 
   /**
@@ -82,11 +118,7 @@ class Account {
     if (!isPrivateKey(prv)) {
       throw new Error('key gen failed');
     }
-    this.privateKey = prv;
-    this.publicKey = getPubkeyFromPrivateKey(this.privateKey);
-    this.address = getAddressFromPrivateKey(this.privateKey);
-
-    return this;
+    return this._import(prv);
   }
 
   /**
@@ -101,7 +133,7 @@ class Account {
     this.privateKey = key;
     this.publicKey = getPubkeyFromPrivateKey(this.privateKey);
     this.address = getAddressFromPrivateKey(this.privateKey);
-
+    this.shards = new Map().set('default', '');
     return this;
   }
 }
diff --git a/packages/harmony-crypto/package.json b/packages/harmony-crypto/package.json
index 634dab6..fe4de10 100644
--- a/packages/harmony-crypto/package.json
+++ b/packages/harmony-crypto/package.json
@@ -17,6 +17,7 @@
   },
   "license": "ISC",
   "dependencies": {
+    "@harmony/utils":"^0.0.1",
     "aes-js": "^3.1.2",
     "bip39": "^2.5.0",
     "bn.js": "^4.11.8",
diff --git a/packages/harmony-crypto/src/bytes.ts b/packages/harmony-crypto/src/bytes.ts
index 1887099..df13895 100644
--- a/packages/harmony-crypto/src/bytes.ts
+++ b/packages/harmony-crypto/src/bytes.ts
@@ -402,3 +402,56 @@ export function joinSignature(signature: Signature): string {
     ]),
   );
 }
+
+/**
+ * hexToByteArray
+ *
+ * Convers a hex string to a Uint8Array
+ *
+ * @param {string} hex
+ * @returns {Uint8Array}
+ */
+export const hexToByteArray = (hex: string): Uint8Array => {
+  const res = new Uint8Array(hex.length / 2);
+
+  for (let i = 0; i < hex.length; i += 2) {
+    res[i / 2] = parseInt(hex.substring(i, i + 2), 16);
+  }
+
+  return res;
+};
+
+/**
+ * hexToIntArray
+ *
+ * @param {string} hex
+ * @returns {number[]}
+ */
+export const hexToIntArray = (hex: string): number[] => {
+  if (!hex || !isHex(hex)) {
+    return [];
+  }
+
+  const res = [];
+
+  for (let i = 0; i < hex.length; i++) {
+    const c = hex.charCodeAt(i);
+    const hi = c >> 8;
+    const lo = c & 0xff;
+
+    hi ? res.push(hi, lo) : res.push(lo);
+  }
+
+  return res;
+};
+
+/**
+ * isHex
+ *
+ * @param {string} str - string to be tested
+ * @returns {boolean}
+ */
+export const isHex = (str: string): boolean => {
+  const plain = str.replace('0x', '');
+  return /[0-9a-f]*$/i.test(plain);
+};
diff --git a/packages/harmony-crypto/src/index.ts b/packages/harmony-crypto/src/index.ts
index 57b07d3..2143720 100644
--- a/packages/harmony-crypto/src/index.ts
+++ b/packages/harmony-crypto/src/index.ts
@@ -1,2 +1,6 @@
 export * from './random';
 export * from './keyTool';
+export * from './keystore';
+
+// export types
+export * from './types';
diff --git a/packages/harmony-crypto/src/keystore.ts b/packages/harmony-crypto/src/keystore.ts
index e69de29..e07559a 100644
--- a/packages/harmony-crypto/src/keystore.ts
+++ b/packages/harmony-crypto/src/keystore.ts
@@ -0,0 +1,171 @@
+import aes from 'aes-js';
+import scrypt from 'scrypt.js';
+import { pbkdf2Sync } from 'pbkdf2';
+import uuid from 'uuid';
+import { isPrivateKey } from '@harmony/utils';
+import { randomBytes } from './random';
+import { getAddressFromPrivateKey } from './keyTool';
+import {
+  concat,
+  //   arrayify,
+  //   hexDataLength,
+  //   hexToByteArray,
+  hexToIntArray,
+} from './bytes';
+import { keccak256 } from './keccak256';
+import {
+  KDF,
+  KDFParams,
+  EncryptOptions,
+  PBKDF2Params,
+  ScryptParams,
+  Keystore,
+} from './types';
+
+const DEFAULT_ALGORITHM = 'aes-128-ctr';
+
+/**
+ * getDerivedKey
+ *
+ * NOTE: only scrypt and pbkdf2 are supported.
+ *
+ * @param {Buffer} key - the passphrase
+ * @param {KDF} kdf - the key derivation function to be used
+ * @param {KDFParams} params - params for the kdf
+ *
+ * @returns {Promise<Buffer>}
+ */
+async function getDerivedKey(
+  key: Buffer,
+  kdf: KDF,
+  params: KDFParams,
+): Promise<Buffer> {
+  const salt = Buffer.from(params.salt, 'hex');
+
+  if (kdf === 'pbkdf2') {
+    const { c, dklen } = params as PBKDF2Params;
+    return pbkdf2Sync(key, salt, c, dklen, 'sha256');
+  }
+
+  if (kdf === 'scrypt') {
+    const { n, r, p, dklen } = params as ScryptParams;
+    return scrypt(key, salt, n, r, p, dklen);
+  }
+
+  throw new Error('Only pbkdf2 and scrypt are supported');
+}
+
+/**
+ * This method will map the current Account object to V3Keystore object.
+ *
+ * @method encrypt
+ *
+ * @param {string} privateKey
+ * @param {string} password
+ * @param {object} options
+ *
+ * @return {{version, id, address, crypto}}
+ */
+export const encrypt = async (
+  privateKey: string,
+  password: string,
+  options?: EncryptOptions,
+): Promise<string> => {
+  if (!isPrivateKey(privateKey)) {
+    throw new Error('privateKey is not correct');
+  }
+  // TODO: should use isString() to implement this
+
+  if (!password) {
+    throw new Error('password is not found');
+  }
+  const address = getAddressFromPrivateKey(privateKey);
+
+  const salt = randomBytes(32);
+  const iv = Buffer.from(randomBytes(16), 'hex');
+  const kdf =
+    options !== undefined ? (options.kdf ? options.kdf : 'scrypt') : 'scrypt';
+  const level =
+    options !== undefined ? (options.level ? options.level : 8192) : 8192;
+
+  const uuidRandom = options !== undefined ? options.uuid : undefined;
+
+  const n = kdf === 'pbkdf2' ? 262144 : level;
+  const kdfparams = {
+    salt,
+    n,
+    r: 8,
+    p: 1,
+    dklen: 32,
+  };
+
+  const derivedKey = await getDerivedKey(Buffer.from(password), kdf, kdfparams);
+  const cipher = new aes.ModeOfOperation.ctr(
+    derivedKey.slice(0, 16),
+    new aes.Counter(iv),
+  );
+
+  if (!cipher) {
+    throw new Error('Unsupported cipher');
+  }
+
+  const ciphertext = Buffer.from(
+    cipher.encrypt(Buffer.from(privateKey.replace('0x', ''), 'hex')),
+  );
+
+  const mac = keccak256(concat([derivedKey.slice(16, 32), ciphertext]));
+
+  return JSON.stringify({
+    version: 3,
+    id: uuid.v4({ random: uuidRandom || hexToIntArray(randomBytes(16)) }),
+    address: address.toLowerCase().replace('0x', ''),
+    crypto: {
+      ciphertext: ciphertext.toString('hex'),
+      cipherparams: {
+        iv: iv.toString('hex'),
+      },
+      cipher: DEFAULT_ALGORITHM,
+      kdf,
+      kdfparams,
+      mac: mac.replace('0x', ''),
+    },
+  });
+};
+
+/**
+ * @function decrypt
+ * @param  {Keystore} keystore - Keystore file
+ * @param  {string} password - password string
+ * @return {string} privateKey
+ */
+export const decrypt = async (
+  keystore: Keystore,
+  password: string,
+): Promise<string> => {
+  const ciphertext = Buffer.from(keystore.crypto.ciphertext, 'hex');
+  const iv = Buffer.from(keystore.crypto.cipherparams.iv, 'hex');
+  const { kdfparams } = keystore.crypto;
+
+  const derivedKey = await getDerivedKey(
+    Buffer.from(password),
+    keystore.crypto.kdf,
+    kdfparams,
+  );
+
+  const mac = keccak256(concat([derivedKey.slice(16, 32), ciphertext])).replace(
+    '0x',
+    '',
+  );
+
+  if (mac.toUpperCase() !== keystore.crypto.mac.toUpperCase()) {
+    return Promise.reject(new Error('Failed to decrypt.'));
+  }
+
+  const CTR = aes.ModeOfOperation.ctr;
+
+  const cipher = new CTR(derivedKey.slice(0, 16), new aes.Counter(iv));
+
+  const decrypted =
+    '0x' + Buffer.from(cipher.decrypt(ciphertext)).toString('hex');
+  return decrypted;
+};
diff --git a/packages/harmony-crypto/src/types.ts b/packages/harmony-crypto/src/types.ts
index e69de29..8e28d4a 100644
--- a/packages/harmony-crypto/src/types.ts
+++ b/packages/harmony-crypto/src/types.ts
@@ -0,0 +1,39 @@
+export type KDF = 'pbkdf2' | 'scrypt';
+
+export interface PBKDF2Params {
+  salt: string;
+  dklen: number;
+  c: number;
+}
+
+export interface ScryptParams {
+  salt: string;
+  dklen: number;
+  n: number;
+  r: number;
+  p: number;
+}
+
+export type KDFParams = PBKDF2Params | ScryptParams;
+
+export interface EncryptOptions {
+  kdf?: KDF;
+  level?: number;
+  uuid?: number[];
+}
+
+export interface Keystore {
+  address: string;
+  crypto: {
+    cipher: string;
+    cipherparams: {
+      iv: string;
+    };
+    ciphertext: string;
+    kdf: KDF;
+    kdfparams: KDFParams;
+    mac: string;
+  };
+  id: string;
+  version: 3;
+}
diff --git a/packages/harmony-network/package.json b/packages/harmony-network/package.json
index cce2657..2fa7d54 100644
--- a/packages/harmony-network/package.json
+++ b/packages/harmony-network/package.json
@@ -1,8 +1,13 @@
 {
-  "name": "harmony-network",
+  "name": "@harmony/network",
   "version": "0.0.1",
-  "description": "network packages for harmony",
-  "main": "index.js",
+  "description": "network suites for harmony",
+  "main": "lib/index.js",
+  "node": "lib/index.js",
+  "browser": "dist/index.js",
+  "module": "dist/index.js",
+  "jsnext:main": "dist/index.js",
+  "typings":"lib/index.d.ts",
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1"
   },
diff --git a/packages/harmony-network/tsconfig.json b/packages/harmony-network/tsconfig.json
new file mode 100644
index 0000000..10487be
--- /dev/null
+++ b/packages/harmony-network/tsconfig.json
@@ -0,0 +1,8 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "outDir": "lib",
+    "rootDir": "src"
+  },
+  "include": ["src", "../../typings/**/*.d.ts"]
+}
diff --git a/scripts/packages.js b/scripts/packages.js
index a10ad93..4e13a93 100644
--- a/scripts/packages.js
+++ b/scripts/packages.js
@@ -2,5 +2,5 @@ export default [
   'harmony-utils',
   'harmony-crypto',
   'harmony-account',
-  // 'harmony-network',
+  'harmony-network',
 ];
diff --git a/scripts/packagesList.js b/scripts/packagesList.js
index dbd5a9b..c4f995b 100644
--- a/scripts/packagesList.js
+++ b/scripts/packagesList.js
@@ -1,10 +1,5 @@
 module.exports = [
-  // { name: 'LaksaUtil', dest: 'laksa-utils' },
-  // { name: 'LaksaZil', dest: 'laksa-zil' },
-  // { name: 'LaksaCrypto', dest: 'laksa-core-crypto' },
-  // { name: 'LaksaWallet', dest: 'laksa-wallet' },
-  // { name: 'LaksaHDWallet', dest: 'laksa-hd-wallet' },
-  // { name: 'LaksaContract', dest: 'laksa-core-contract' },
+  { name: 'HarmonyNetwork', dest: 'harmony-network' },
   { name: 'HarmonyUtils', dest: 'harmony-utils' },
   { name: 'HarmonyCrypto', dest: 'harmony-crypto' },
   { name: 'HarmonyAccount', dest: 'harmony-account' },
diff --git a/scripts/packagesTs.ts b/scripts/packagesTs.ts
index 6b50330..2c8b042 100644
--- a/scripts/packagesTs.ts
+++ b/scripts/packagesTs.ts
@@ -2,7 +2,7 @@ const packages = [
   'harmony-utils',
   'harmony-crypto',
   'harmony-account',
-  // 'harmony-network',
+  'harmony-network',
 ];
 
 export { packages };
diff --git a/tsconfig.json b/tsconfig.json
index 5ebd1ca..18f41fa 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -3,6 +3,7 @@
   "references": [
     { "path": "packages/harmony-account" },
     { "path": "packages/harmony-crypto" },
-    { "path": "packages/harmony-utils" }
+    { "path": "packages/harmony-utils" },
+    { "path": "packages/harmony-network" }
   ]
 }
diff --git a/typings/aes-js.d.ts b/typings/aes-js.d.ts
new file mode 100644
index 0000000..799196f
--- /dev/null
+++ b/typings/aes-js.d.ts
@@ -0,0 +1,16 @@
+declare module 'aes-js' {
+  export class Counter {
+    constructor(iv: Buffer);
+    setValue(value: number): void;
+    setBytes(bytes: Array<number> | Buffer | string): void;
+    increment(): void;
+  }
+
+  class CTR {
+    constructor(derivedKey: Buffer, iv: Counter);
+    encrypt(bytes: Buffer): Uint8Array;
+    decrypt(bytes: Buffer): Uint8Array;
+  }
+
+  export const ModeOfOperation: { ctr: typeof CTR };
+}
diff --git a/typings/scrypt.d.ts b/typings/scrypt.d.ts
new file mode 100644
index 0000000..b6efa20
--- /dev/null
+++ b/typings/scrypt.d.ts
@@ -0,0 +1,11 @@
+declare module 'scrypt.js' {
+  export default function scrypt(
+    key: Buffer,
+    salt: Buffer,
+    n: number,
+    r: number,
+    p: number,
+    dklen: number,
+    progressCB?: (prog: any) => void,
+  ): Buffer;
+}