diff --git a/.flowconfig b/.flowconfig
index abe6b5cef..0cff1d89d 100644
--- a/.flowconfig
+++ b/.flowconfig
@@ -1,6 +1,7 @@
 [ignore]
 <PROJECT_ROOT>/build
 <PROJECT_ROOT>/packages/.*/build
+<PROJECT_ROOT>/node_modules/ethereumjs-testing
 
 [include]
 
@@ -12,5 +13,5 @@ all=warn
 
 [options]
 include_warnings=true
-module.name_mapper='^@polkadot/util-\(crypto\|triehash\)\(.*\)$' -> '<PROJECT_ROOT>/packages/util-\1/src\2'
+module.name_mapper='^@polkadot/util-\(crypto\|rlp\|triehash\)\(.*\)$' -> '<PROJECT_ROOT>/packages/util-\1/src\2'
 module.name_mapper='^@polkadot/util\(.*\)$' -> '<PROJECT_ROOT>/packages/util/src\1'
diff --git a/README.md b/README.md
index 59ac64ee8..0eb2569a3 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,7 @@ It is split up into a number of internal packages -
 
 - [packages/util](packages/util/) General utilities
 - [packages/util-crypto](packages/util-crypto/) Crypto and hashing utilities
+- [packages/util-rlp](packages/util-rlp/) RLP encoding & decoding
 - [packages/util-triehash](packages/util-triehash/) Calculation of trie hashes
 
 ## Contributing
diff --git a/jest.config.js b/jest.config.js
index f4c4d2a86..bd77b1f47 100644
--- a/jest.config.js
+++ b/jest.config.js
@@ -2,7 +2,7 @@ const config = require('@polkadot/dev/config/jest');
 
 module.exports = Object.assign({}, config, {
   moduleNameMapper: {
-    '@polkadot/util-(crypto|triehash)(.*)$': '<rootDir>/packages/util-$1/src/$2',
+    '@polkadot/util-(crypto|rlp|triehash)(.*)$': '<rootDir>/packages/util-$1/src/$2',
     '@polkadot/util(.*)$': '<rootDir>/packages/util/src/$1'
   }
 });
diff --git a/package.json b/package.json
index be4cb2c7b..f9700614d 100644
--- a/package.json
+++ b/package.json
@@ -10,7 +10,7 @@
     "test": "jest --coverage"
   },
   "devDependencies": {
-    "@polkadot/dev": "^0.15.2",
+    "@polkadot/dev": "^0.15.6",
     "lerna": "^2.5.1"
   }
 }
diff --git a/packages/util-crypto/docs/keccak.md b/packages/util-crypto/docs/keccak.md
index 73a713a3e..5904a6da5 100644
--- a/packages/util-crypto/docs/keccak.md
+++ b/packages/util-crypto/docs/keccak.md
@@ -12,7 +12,7 @@ Create Keccak256 values as hex, string, Buffer & Uint8Array output
 Creates a keccak Buffer from the input. 
 
 ```js
-keccakAsBuffer (value: Buffer | string): Buffer
+keccakAsBuffer (value: Buffer | Uint8Array | string): Buffer
 ```
 
 
@@ -29,7 +29,7 @@ console.log('asBuffer', keccakAsBuffer('123')) // => Buffer
 Creates a keccak hex string from the input. 
 
 ```js
-keccakAsHex (value: Buffer | string): string
+keccakAsHex (value: Buffer | Uint8Array | string): string
 ```
 
 
@@ -46,7 +46,7 @@ console.log('asHex', keccakAsHex('123')) // => 0x...
 Creates a keccak string from the input. 
 
 ```js
-keccakAsString (value: Buffer | string): string
+keccakAsString (value: Buffer | Uint8Array | string): string
 ```
 
 
@@ -63,7 +63,7 @@ console.log('asString', keccakAsString('123')) // => string
 Creates a keccak Uint8Array from the input. 
 
 ```js
-keccakAsU8a (value: Buffer | string): Uint8Array
+keccakAsU8a (value: Buffer | Uint8Array | string): Uint8Array
 ```
 
 
diff --git a/packages/util-crypto/package.json b/packages/util-crypto/package.json
index 30ad13d0c..39a29ad8b 100644
--- a/packages/util-crypto/package.json
+++ b/packages/util-crypto/package.json
@@ -31,7 +31,7 @@
   "dependencies": {
     "babel-runtime": "^6.26.0",
     "blakejs": "^1.1.0",
-    "keccak": "^1.3.0",
+    "keccak": "jacogr/keccak#f25ae4b299038bb2f0b72f150b99b5048ffb9e48",
     "tweetnacl": "^1.0.0",
     "xxhashjs": "^0.2.2"
   }
diff --git a/packages/util-crypto/src/keccak/asBuffer.js b/packages/util-crypto/src/keccak/asBuffer.js
index b47b7119c..c1c735460 100644
--- a/packages/util-crypto/src/keccak/asBuffer.js
+++ b/packages/util-crypto/src/keccak/asBuffer.js
@@ -7,7 +7,7 @@ const createKeccak = require('keccak');
 
 /**
   @name keccakAsBuffer
-  @signature keccakAsBuffer (value: Buffer | string): Buffer
+  @signature keccakAsBuffer (value: Buffer | Uint8Array | string): Buffer
   @summary Creates a keccak Buffer from the input.
   @description
     From either a `string` or a `Buffer` input, create the keccak and return the result as a `Buffer`.
@@ -16,6 +16,8 @@ const createKeccak = require('keccak');
 
     console.log('asBuffer', keccakAsBuffer('123')) // => Buffer
 */
-module.exports = function keccakAsBuffer (value: Buffer | string): Buffer {
-  return createKeccak('keccak256').update(value).digest();
+module.exports = function keccakAsBuffer (value: Buffer | Uint8Array | string): Buffer {
+  // HACK: For the time being, don't change the definition (although fork of library is used)
+  // flowlint-next-line unclear-type:off
+  return createKeccak('keccak256').update(((value: any): Buffer)).digest();
 };
diff --git a/packages/util-crypto/src/keccak/asBuffer.spec.js b/packages/util-crypto/src/keccak/asBuffer.spec.js
index b2297768d..673b57672 100644
--- a/packages/util-crypto/src/keccak/asBuffer.spec.js
+++ b/packages/util-crypto/src/keccak/asBuffer.spec.js
@@ -2,6 +2,8 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
+const u8aFromString = require('@polkadot/util/u8a/fromString');
+
 const { keccakAsBuffer } = require('./index');
 
 const value = 'test value';
@@ -15,4 +17,12 @@ describe('keccakAsBuffer', () => {
       )
     ).toEqual(true);
   });
+
+  it('returns an hex representation (Uint8Array input)', () => {
+    expect(
+      keccakAsBuffer(u8aFromString(value)).equals(
+        Buffer.from(result, 'hex')
+      )
+    ).toEqual(true);
+  });
 });
diff --git a/packages/util-crypto/src/keccak/asHex.js b/packages/util-crypto/src/keccak/asHex.js
index b1e1190f3..74ae1e2cc 100644
--- a/packages/util-crypto/src/keccak/asHex.js
+++ b/packages/util-crypto/src/keccak/asHex.js
@@ -9,7 +9,7 @@ const keccakAsBuffer = require('./asBuffer');
 
 /**
   @name keccakAsHex
-  @signature keccakAsHex (value: Buffer | string): string
+  @signature keccakAsHex (value: Buffer | Uint8Array | string): string
   @summary Creates a keccak hex string from the input.
   @description
     From either a `string` or a `Buffer` input, create the keccak and return the result as a `0x` prefixed hex string.
@@ -18,7 +18,7 @@ const keccakAsBuffer = require('./asBuffer');
 
     console.log('asHex', keccakAsHex('123')) // => 0x...
 */
-module.exports = function keccakAsHex (value: Buffer | string): string {
+module.exports = function keccakAsHex (value: Buffer | Uint8Array | string): string {
   return bufferToHex(
     keccakAsBuffer(value)
   );
diff --git a/packages/util-crypto/src/keccak/asString.js b/packages/util-crypto/src/keccak/asString.js
index 521a84472..aaeefe0e8 100644
--- a/packages/util-crypto/src/keccak/asString.js
+++ b/packages/util-crypto/src/keccak/asString.js
@@ -7,7 +7,7 @@ const keccakAsBuffer = require('./asBuffer');
 
 /**
   @name keccakAsString
-  @signature keccakAsString (value: Buffer | string): string
+  @signature keccakAsString (value: Buffer | Uint8Array | string): string
   @summary Creates a keccak string from the input.
   @description
     From either a `string` or a `Buffer` input, create the keccak and return the result as a non-prefixed string.
@@ -16,6 +16,6 @@ const keccakAsBuffer = require('./asBuffer');
 
     console.log('asString', keccakAsString('123')) // => string
 */
-module.exports = function keccakAsString (value: Buffer | string): string {
+module.exports = function keccakAsString (value: Buffer | Uint8Array | string): string {
   return keccakAsBuffer(value).toString('hex');
 };
diff --git a/packages/util-crypto/src/keccak/asU8a.js b/packages/util-crypto/src/keccak/asU8a.js
index 7ff659b88..2092c7e2a 100644
--- a/packages/util-crypto/src/keccak/asU8a.js
+++ b/packages/util-crypto/src/keccak/asU8a.js
@@ -4,11 +4,11 @@
 // @flow
 
 const bufferToU8a = require('@polkadot/util/buffer/toU8a');
-const createKeccak = require('keccak');
+const keccakAsBuffer = require('./asBuffer');
 
 /**
   @name keccakAsU8a
-  @signature keccakAsU8a (value: Buffer | string): Uint8Array
+  @signature keccakAsU8a (value: Buffer | Uint8Array | string): Uint8Array
   @summary Creates a keccak Uint8Array from the input.
   @description
     From either a `string` or a `Buffer` input, create the keccak and return the result as a `Uint8Array`.
@@ -17,8 +17,8 @@ const createKeccak = require('keccak');
 
     keccakAsU8a('123') // => Uint8Array
 */
-module.exports = function keccakAsU8a (value: Buffer | string): Uint8Array {
+module.exports = function keccakAsU8a (value: Buffer | Uint8Array | string): Uint8Array {
   return bufferToU8a(
-    createKeccak('keccak256').update(value).digest()
+    keccakAsBuffer(value)
   );
 };
diff --git a/packages/util-rlp/LICENSE b/packages/util-rlp/LICENSE
new file mode 100644
index 000000000..3d150a620
--- /dev/null
+++ b/packages/util-rlp/LICENSE
@@ -0,0 +1,15 @@
+ISC License (ISC)
+
+Copyright 2017-2018 Jaco Greeff <jacogr@gmail.com>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+PERFORMANCE OF THIS SOFTWARE.
diff --git a/packages/util-rlp/README.md b/packages/util-rlp/README.md
new file mode 100644
index 000000000..fd4fbb850
--- /dev/null
+++ b/packages/util-rlp/README.md
@@ -0,0 +1,17 @@
+[![polkadotjs](https://img.shields.io/badge/polkadot-js-orange.svg?style=flat-square)](https://polkadot.js.org)
+![isc](https://img.shields.io/badge/license-ISC-lightgrey.svg?style=flat-square)
+[![style](https://img.shields.io/badge/code%20style-semistandard-lightgrey.svg?style=flat-square)](https://github.com/Flet/semistandard)
+[![npm](https://img.shields.io/npm/v/@polkadot/util-rlp.svg?style=flat-square)](https://www.npmjs.com/package/@polkadot/util-rlp)
+[![travis](https://img.shields.io/travis/polkadot-js/util.svg?style=flat-square)](https://travis-ci.org/polkadot-js/util)
+[![maintainability](https://img.shields.io/codeclimate/maintainability/polkadot-js/util.svg?style=flat-square)](https://codeclimate.com/github/polkadot-js/util/maintainability)
+[![coverage](https://img.shields.io/coveralls/polkadot-js/util.svg?style=flat-square)](https://coveralls.io/github/polkadot-js/util?branch=master)
+[![dependency](https://david-dm.org/polkadot-js/util.svg?style=flat-square&path=packages/util)](https://david-dm.org/polkadot-js/util?path=packages/util-rlp)
+[![devDependency](https://david-dm.org/polkadot-js/util/dev-status.svg?style=flat-square&path=packages/util-rlp)](https://david-dm.org/polkadot-js/util?path=packages/util-rlp#info=devDependencies)
+
+# @polkadot/util-rlp
+
+Encoding and decoding for [Ethereum RLP structures](https://github.com/ethereum/wiki/wiki/%5BEnglish%5D-RLP). This is port of the original [EthereumJS RLP](https://github.com/ethereumjs/rlp) to cater for `Uint8Array` outputs (instead of `Buffer`) in addition to typings.
+
+## Available Utilities
+
+For a list of currently exposed methods, see the [library documentation](docs/README.md).
diff --git a/packages/util-rlp/docs/README.md b/packages/util-rlp/docs/README.md
new file mode 100644
index 000000000..367df6d59
--- /dev/null
+++ b/packages/util-rlp/docs/README.md
@@ -0,0 +1,40 @@
+# Available interfaces
+
+Utility methods to encode and decode [Ethereum RLP](https://github.com/ethereum/wiki/wiki/RLP). Adapted from the [EthereumJS implementation](https://github.com/ethereumjs/rlp/blob/0ce09db81fc303fcee593f7cc094ba44015f9b92/index.js) 
+
+
+# Available methods
+
+## decode
+
+Decodes the input RLP. 
+
+```js
+decoder (input?: Uint8Array): Uint8Array | Array<*>
+```
+
+
+From an input, decod the RLP and return the result as a `Uint8Array` or `Array`.
+
+```js
+import { decode } from '@polkadot/util-rlp';
+
+encode(new Uint8Array([0x83, 0x64, 0x6f, 0x67])) // => 'dog' as Uint8Array
+```
+
+## encode
+
+Encodes the input value into RLP. 
+
+```js
+encode (input: any): Uint8Array
+```
+
+
+From an input, calculate the RLP and return the result as a `Uint8Array`.
+
+```js
+import { encode } from '@polkadot/util-rlp';
+
+encode('dog') // => [0x83, 0x64, 0x6f, 0x67]
+```
\ No newline at end of file
diff --git a/packages/util-rlp/package.json b/packages/util-rlp/package.json
new file mode 100644
index 000000000..942ed7cee
--- /dev/null
+++ b/packages/util-rlp/package.json
@@ -0,0 +1,38 @@
+{
+  "name": "@polkadot/util-rlp",
+  "version": "0.14.1",
+  "description": "RLP encoding and decoding",
+  "main": "index.js",
+  "keywords": [
+    "Polkadot"
+  ],
+  "author": "Jaco Greeff <jacogr@gmail.com>",
+  "license": "ISC",
+  "engines": {
+    "node": ">=6.4"
+  },
+  "publishConfig": {
+    "access": "public",
+    "registry": "https://registry.npmjs.org"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/polkadot-js/util.git"
+  },
+  "bugs": {
+    "url": "https://github.com/polkadot-js/util/issues"
+  },
+  "homepage": "https://github.com/polkadot-js/util/tree/master/packages/util-triehash#readme",
+  "scripts": {
+    "build": "polkadot-dev-build-babel && polkadot-dev-build-docs",
+    "check": "eslint src && flow check",
+    "test": "echo \"Tests only available from root wrapper\""
+  },
+  "dependencies": {
+    "@polkadot/util": "^0.14.1",
+    "babel-runtime": "^6.26.0"
+  },
+  "devDependencies": {
+    "ethereumjs-testing": "^1.0.4"
+  }
+}
diff --git a/packages/util-rlp/src/decode.js b/packages/util-rlp/src/decode.js
new file mode 100644
index 000000000..43ce8e691
--- /dev/null
+++ b/packages/util-rlp/src/decode.js
@@ -0,0 +1,19 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+const decoder = require('./decoder');
+
+/**
+  @name decode
+  @signature decoder (input?: Uint8Array): Uint8Array | Array<*>
+  @summary Decodes the input RLP.
+  @description
+    From an input, decod the RLP and return the result as a `Uint8Array` or `Array`.
+  @example
+    import { decode } from '@polkadot/util-rlp';
+
+    encode(new Uint8Array([0x83, 0x64, 0x6f, 0x67])) // => 'dog' as Uint8Array
+*/
+module.exports = decoder;
diff --git a/packages/util-rlp/src/decode.spec.js b/packages/util-rlp/src/decode.spec.js
new file mode 100644
index 000000000..b5db663b6
--- /dev/null
+++ b/packages/util-rlp/src/decode.spec.js
@@ -0,0 +1,42 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+
+const hexToU8a = require('@polkadot/util/hex/toU8a');
+const u8aToHex = require('@polkadot/util/u8a/toHex');
+
+const { decode, encode } = require('./index');
+
+const rlptests = require('../test/getTests')('RLPTests/rlptest.json');
+
+describe('decode', () => {
+  it('returns empty list for undefined inputs', () => {
+    expect(
+      decode()
+    ).toEqual(
+      new Uint8Array([])
+    );
+  });
+
+  it('returns empty list for empty inputs', () => {
+    expect(
+      decode([])
+    ).toEqual(
+      new Uint8Array([])
+    );
+  });
+
+  rlptests.forEach(({ name, output }) => {
+    it(`passes official ${name}`, () => {
+      expect(
+        u8aToHex(
+          encode(
+            decode(
+              hexToU8a(output)
+            )
+          )
+        )
+      ).toEqual(output);
+    });
+  });
+});
diff --git a/packages/util-rlp/src/decoder/.nodoc b/packages/util-rlp/src/decoder/.nodoc
new file mode 100644
index 000000000..e69de29bb
diff --git a/packages/util-rlp/src/decoder/decode.js b/packages/util-rlp/src/decoder/decode.js
new file mode 100644
index 000000000..09a333e8b
--- /dev/null
+++ b/packages/util-rlp/src/decoder/decode.js
@@ -0,0 +1,42 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { DecodeOutput } from './types';
+
+const decodeListLong = require('./listLong');
+const decodeListShort = require('./listShort');
+const decodeNumber = require('./number');
+const decodeSingle = require('./single');
+const decodeString = require('./string');
+
+function decode (input: Uint8Array): DecodeOutput {
+  const firstByte = input[0];
+
+  // a single byte whose value is in the [0x00, 0x7f] range, that byte is its own RLP encoding
+  if (firstByte <= 0x7f) {
+    return decodeSingle(decode, input);
+  }
+
+  // string is 0-55 bytes long. A single byte with value 0x80 plus the length of the string followed by the string
+  // The range of the first byte is [0x80, 0xb7]
+  if (firstByte <= 0xb7) {
+    return decodeString(decode, input);
+  }
+
+  // a number
+  if (firstByte <= 0xbf) {
+    return decodeNumber(decode, input);
+  }
+
+  // a list between  0-55 bytes long
+  if (firstByte <= 0xf7) {
+    return decodeListShort(decode, input);
+  }
+
+  // a list  over 55 bytes long
+  return decodeListLong(decode, input);
+}
+
+module.exports = decode;
diff --git a/packages/util-rlp/src/decoder/index.js b/packages/util-rlp/src/decoder/index.js
new file mode 100644
index 000000000..171a780a9
--- /dev/null
+++ b/packages/util-rlp/src/decoder/index.js
@@ -0,0 +1,20 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+const assert = require('@polkadot/util/assert');
+
+const internalDecode = require('./decode');
+
+module.exports = function decoder (input?: Uint8Array): Uint8Array | Array<*> {
+  if (!input || input.length === 0) {
+    return new Uint8Array([]);
+  }
+
+  const { decoded, remainder } = internalDecode(input);
+
+  assert(remainder.length === 0, 'invalid remainder');
+
+  return decoded;
+};
diff --git a/packages/util-rlp/src/decoder/listLong.js b/packages/util-rlp/src/decoder/listLong.js
new file mode 100644
index 000000000..4a8ffd56d
--- /dev/null
+++ b/packages/util-rlp/src/decoder/listLong.js
@@ -0,0 +1,35 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { DecodeFunc, DecodeOutput } from './types';
+
+const assert = require('@polkadot/util/assert');
+
+const safeParseInt = require('./safeParseInt');
+
+module.exports = function decodeListLong (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
+  const llength = input[0] - 0xf6;
+  const length = safeParseInt(input.slice(1, llength));
+  const totalLength = llength + length;
+  const decoded = [];
+
+  assert(totalLength <= input.length, 'invalid rlp: total length is larger than the data');
+
+  let innerRemainder = input.slice(llength, totalLength);
+
+  assert(innerRemainder.length > 0, 'invalid rlp, List has a invalid length');
+
+  while (innerRemainder.length) {
+    const d = decode(innerRemainder);
+
+    decoded.push(d.decoded);
+    innerRemainder = d.remainder;
+  }
+
+  return {
+    decoded,
+    remainder: input.slice(totalLength)
+  };
+};
diff --git a/packages/util-rlp/src/decoder/listShort.js b/packages/util-rlp/src/decoder/listShort.js
new file mode 100644
index 000000000..da5f18e22
--- /dev/null
+++ b/packages/util-rlp/src/decoder/listShort.js
@@ -0,0 +1,24 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { DecodeFunc, DecodeOutput } from './types';
+
+module.exports = function decodeListShort (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
+  const length = input[0] - 0xbf;
+  let innerRemainder = input.slice(1, length);
+  const decoded = [];
+
+  while (innerRemainder.length) {
+    const d = decode(innerRemainder);
+
+    decoded.push(d.decoded);
+    innerRemainder = d.remainder;
+  }
+
+  return {
+    decoded,
+    remainder: input.slice(length)
+  };
+};
diff --git a/packages/util-rlp/src/decoder/number.js b/packages/util-rlp/src/decoder/number.js
new file mode 100644
index 000000000..e95b69532
--- /dev/null
+++ b/packages/util-rlp/src/decoder/number.js
@@ -0,0 +1,23 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { DecodeFunc, DecodeOutput } from './types';
+
+const assert = require('@polkadot/util/assert');
+
+const safeParseInt = require('./safeParseInt');
+
+module.exports = function decodeNumber (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
+  const llength = input[0] - 0xb6;
+  const length = safeParseInt(input.slice(1, llength));
+  const decoded = input.slice(llength, length + llength);
+
+  assert(decoded.length === length, 'invalid RLP');
+
+  return {
+    decoded,
+    remainder: input.slice(length + llength)
+  };
+};
diff --git a/packages/util-rlp/src/decoder/safeParseInt.js b/packages/util-rlp/src/decoder/safeParseInt.js
new file mode 100644
index 000000000..ce8f82241
--- /dev/null
+++ b/packages/util-rlp/src/decoder/safeParseInt.js
@@ -0,0 +1,12 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+const assert = require('@polkadot/util/assert');
+
+module.exports = function safeParseInt (input: Uint8Array): number {
+  assert(input[0] > 0, 'invalid RLP: extra zeros');
+
+  return input.reduce((result, value) => (result * 256) + value, 0);
+};
diff --git a/packages/util-rlp/src/decoder/safeParseInt.spec.js b/packages/util-rlp/src/decoder/safeParseInt.spec.js
new file mode 100644
index 000000000..be37100ed
--- /dev/null
+++ b/packages/util-rlp/src/decoder/safeParseInt.spec.js
@@ -0,0 +1,24 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+const safeParseInt = require('./safeParseInt');
+
+describe('safeParseInt', () => {
+  it('does not allow 0 in first position', () => {
+    expect(
+      () => safeParseInt(
+        new Uint8Array([0])
+      )
+    ).toThrow(/invalid RLP: extra zeros/);
+  });
+
+  it('converts a value to the correct number', () => {
+    expect(
+      safeParseInt(
+        new Uint8Array([0x12, 0x34, 0x56])
+      )
+    ).toEqual(0x123456);
+  });
+});
diff --git a/packages/util-rlp/src/decoder/single.js b/packages/util-rlp/src/decoder/single.js
new file mode 100644
index 000000000..9576cac55
--- /dev/null
+++ b/packages/util-rlp/src/decoder/single.js
@@ -0,0 +1,13 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { DecodeFunc, DecodeOutput } from './types';
+
+module.exports = function decodeSingle (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
+  return {
+    decoded: input.slice(0, 1),
+    remainder: input.slice(1)
+  };
+};
diff --git a/packages/util-rlp/src/decoder/string.js b/packages/util-rlp/src/decoder/string.js
new file mode 100644
index 000000000..8acde240f
--- /dev/null
+++ b/packages/util-rlp/src/decoder/string.js
@@ -0,0 +1,28 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { DecodeFunc, DecodeOutput } from './types';
+
+const assert = require('@polkadot/util/assert');
+
+module.exports = function decodeString (decode: DecodeFunc, input: Uint8Array): DecodeOutput {
+  const firstByte = input[0];
+  const length = firstByte - 0x7f;
+  let decoded;
+
+  // set 0x80 null to 0
+  if (firstByte === 0x80) {
+    decoded = new Uint8Array([]);
+  } else {
+    decoded = input.slice(1, length);
+  }
+
+  assert(!(length === 2 && decoded[0] < 0x80), 'invalid rlp encoding: byte must be less 0x80');
+
+  return {
+    decoded,
+    remainder: input.slice(length)
+  };
+};
diff --git a/packages/util-rlp/src/decoder/types.js b/packages/util-rlp/src/decoder/types.js
new file mode 100644
index 000000000..18f956241
--- /dev/null
+++ b/packages/util-rlp/src/decoder/types.js
@@ -0,0 +1,11 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+export type DecodeOutput = {
+  decoded: Uint8Array | Array<*>,
+  remainder: Uint8Array
+}
+
+export type DecodeFunc = (input: Uint8Array) => DecodeOutput;
diff --git a/packages/util-rlp/src/encode.js b/packages/util-rlp/src/encode.js
new file mode 100644
index 000000000..9248eaed8
--- /dev/null
+++ b/packages/util-rlp/src/encode.js
@@ -0,0 +1,19 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+const encoder = require('./encoder');
+
+/**
+  @name encode
+  @signature encode (input: any): Uint8Array
+  @summary Encodes the input value into RLP.
+  @description
+    From an input, calculate the RLP and return the result as a `Uint8Array`.
+  @example
+    import { encode } from '@polkadot/util-rlp';
+
+    encode('dog') // => [0x83, 0x64, 0x6f, 0x67]
+*/
+module.exports = encoder;
diff --git a/packages/util-rlp/src/encode.spec.js b/packages/util-rlp/src/encode.spec.js
new file mode 100644
index 000000000..069081b66
--- /dev/null
+++ b/packages/util-rlp/src/encode.spec.js
@@ -0,0 +1,21 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+
+const u8aToHex = require('@polkadot/util/u8a/toHex');
+
+const { encode } = require('./index');
+
+const rlptests = require('../test/getTests')('RLPTests/rlptest.json');
+
+describe('encode', () => {
+  rlptests.forEach(({ name, input, output }) => {
+    it(`passes official ${name}`, () => {
+      expect(
+        u8aToHex(
+          encode(input)
+        )
+      ).toEqual(output);
+    });
+  });
+});
diff --git a/packages/util-rlp/src/encoder/.nodoc b/packages/util-rlp/src/encoder/.nodoc
new file mode 100644
index 000000000..e69de29bb
diff --git a/packages/util-rlp/src/encoder/array.js b/packages/util-rlp/src/encoder/array.js
new file mode 100644
index 000000000..4c76d2f68
--- /dev/null
+++ b/packages/util-rlp/src/encoder/array.js
@@ -0,0 +1,28 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { EncodeFunc } from './types';
+
+const u8aConcat = require('@polkadot/util/u8a/concat');
+
+const encodeLength = require('./length');
+
+// flowlint-next-line unclear-type:off
+module.exports = function encodeArray (encoder: EncodeFunc, input: any): Uint8Array {
+  const output = [];
+
+  for (let i = 0; i < input.length; i++) {
+    output.push(
+      encoder(input[i])
+    );
+  }
+
+  const encoded = u8aConcat(output);
+
+  return u8aConcat([
+    encodeLength(encoded.length, 192),
+    encoded
+  ]);
+};
diff --git a/packages/util-rlp/src/encoder/index.js b/packages/util-rlp/src/encoder/index.js
new file mode 100644
index 000000000..4962ec304
--- /dev/null
+++ b/packages/util-rlp/src/encoder/index.js
@@ -0,0 +1,19 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+const encodeArray = require('./array');
+const toU8a = require('./toU8a');
+const encodeU8a = require('./u8a');
+
+// flowlint-next-line unclear-type:off
+function encoder (input: any): Uint8Array {
+  if (input instanceof Array) {
+    return encodeArray(encoder, input);
+  }
+
+  return encodeU8a(encoder, toU8a(input));
+}
+
+module.exports = encoder;
diff --git a/packages/util-rlp/src/encoder/length.js b/packages/util-rlp/src/encoder/length.js
new file mode 100644
index 000000000..e7e162534
--- /dev/null
+++ b/packages/util-rlp/src/encoder/length.js
@@ -0,0 +1,19 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+const numberToHex = require('@polkadot/util/number/toHex');
+const hexToU8a = require('@polkadot/util/hex/toU8a');
+
+module.exports = function encodeLength (length: number, offset: number): Uint8Array {
+  if (length < 56) {
+    return new Uint8Array([length + offset]);
+  }
+
+  const hexLength = numberToHex(length).slice(2);
+
+  return hexToU8a(
+    numberToHex(offset + 55 + hexLength.length / 2) + hexLength
+  );
+};
diff --git a/packages/util-rlp/src/encoder/length.spec.js b/packages/util-rlp/src/encoder/length.spec.js
new file mode 100644
index 000000000..3eee0bfc9
--- /dev/null
+++ b/packages/util-rlp/src/encoder/length.spec.js
@@ -0,0 +1,31 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+
+const encodeLength = require('./length');
+
+describe('encodeLength', () => {
+  it('returns offset + length where <= 55', () => {
+    expect(
+      encodeLength(5, 6)
+    ).toEqual(
+      new Uint8Array([11])
+    );
+  });
+
+  it('encodes > 55 length properly (short)', () => {
+    expect(
+      encodeLength(56, 6)
+    ).toEqual(
+      new Uint8Array([62, 56])
+    );
+  });
+
+  it('encodes > 55 length properly (long)', () => {
+    expect(
+      encodeLength(512, 6)
+    ).toEqual(
+      new Uint8Array([63, 2, 0])
+    );
+  });
+});
diff --git a/packages/util-rlp/src/encoder/toU8a.js b/packages/util-rlp/src/encoder/toU8a.js
new file mode 100644
index 000000000..b514870d2
--- /dev/null
+++ b/packages/util-rlp/src/encoder/toU8a.js
@@ -0,0 +1,51 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+const bnToU8a = require('@polkadot/util/bn/toU8a');
+const bufferToU8a = require('@polkadot/util/buffer/toU8a');
+const hexHasPrefix = require('@polkadot/util/hex/hasPrefix');
+const hexToU8a = require('@polkadot/util/hex/toU8a');
+const isInstanceOf = require('@polkadot/util/is/instanceOf');
+const isBn = require('@polkadot/util/is/bn');
+const isBuffer = require('@polkadot/util/is/buffer');
+const isNull = require('@polkadot/util/is/null');
+const isNumber = require('@polkadot/util/is/number');
+const isString = require('@polkadot/util/is/string');
+const isUndefined = require('@polkadot/util/is/undefined');
+const numberToU8a = require('@polkadot/util/number/toU8a');
+const u8aFromUtf8 = require('@polkadot/util/u8a/fromUtf8');
+
+// flowlint-next-line unclear-type:off
+module.exports = function toU8a (value: any): Uint8Array {
+  if (isNull(value) || isUndefined(value)) {
+    return new Uint8Array([]);
+  }
+
+  if (isBuffer(value)) {
+    return bufferToU8a(value);
+  }
+
+  if (isInstanceOf(value, Uint8Array)) {
+    return value;
+  }
+
+  if (isNumber(value)) {
+    return numberToU8a(value);
+  }
+
+  if (isString(value)) {
+    if (hexHasPrefix(value)) {
+      return hexToU8a(value);
+    }
+
+    return u8aFromUtf8(value);
+  }
+
+  if (isBn(value)) {
+    return bnToU8a(value);
+  }
+
+  throw new Error('invalid type');
+};
diff --git a/packages/util-rlp/src/encoder/toU8a.spec.js b/packages/util-rlp/src/encoder/toU8a.spec.js
new file mode 100644
index 000000000..29340ac56
--- /dev/null
+++ b/packages/util-rlp/src/encoder/toU8a.spec.js
@@ -0,0 +1,79 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+
+const BN = require('bn.js');
+
+const toU8a = require('./toU8a');
+
+describe('toU8a', () => {
+  it('returns a Uint8Array input as-is', () => {
+    expect(
+      toU8a(new Uint8Array([1, 2, 3]))
+    ).toEqual(
+      new Uint8Array([1, 2, 3])
+    );
+  });
+
+  it('converts Buffers (uses as Uint8Array)', () => {
+    expect(
+      toU8a(Buffer.from([0x12, 0x34, 0x56]))
+    ).toEqual(
+      new Uint8Array([0x12, 0x34, 0x56])
+    );
+  });
+
+  it('returns undefined as empty', () => {
+    expect(
+      toU8a()
+    ).toEqual(
+      new Uint8Array([])
+    );
+  });
+
+  it('returns null as empty', () => {
+    expect(
+      toU8a(null)
+    ).toEqual(
+      new Uint8Array([])
+    );
+  });
+
+  it('converts hex strings', () => {
+    expect(
+      toU8a('0x123456')
+    ).toEqual(
+      new Uint8Array([0x12, 0x34, 0x56])
+    );
+  });
+
+  it('converts UTF-8 strings', () => {
+    expect(
+      toU8a('Привет, мир!')
+    ).toEqual(
+      new Uint8Array([208, 159, 209, 128, 208, 184, 208, 178, 208, 181, 209, 130, 44, 32, 208, 188, 208, 184, 209, 128, 33])
+    );
+  });
+
+  it('converts numbers', () => {
+    expect(
+      toU8a(0x123456)
+    ).toEqual(
+      new Uint8Array([0x12, 0x34, 0x56])
+    );
+  });
+
+  it('converts BN', () => {
+    expect(
+      toU8a(new BN(0x123456))
+    ).toEqual(
+      new Uint8Array([0x12, 0x34, 0x56])
+    );
+  });
+
+  it('throws on unknown type', () => {
+    expect(
+      () => toU8a(true)
+    ).toThrow(/invalid type/);
+  });
+});
diff --git a/packages/util-triehash/src/util/index.js b/packages/util-rlp/src/encoder/types.js
similarity index 64%
rename from packages/util-triehash/src/util/index.js
rename to packages/util-rlp/src/encoder/types.js
index 0a8363f51..6c85acf3c 100644
--- a/packages/util-triehash/src/util/index.js
+++ b/packages/util-rlp/src/encoder/types.js
@@ -3,7 +3,5 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-/**
-  @summary Internal utilities used along with hash generation
-*/
-module.exports = {};
+// flowlint-next-line unclear-type:off
+export type EncodeFunc = (input: any) => Uint8Array;
diff --git a/packages/util-rlp/src/encoder/u8a.js b/packages/util-rlp/src/encoder/u8a.js
new file mode 100644
index 000000000..981836007
--- /dev/null
+++ b/packages/util-rlp/src/encoder/u8a.js
@@ -0,0 +1,21 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { EncodeFunc } from './types';
+
+const u8aConcat = require('@polkadot/util/u8a/concat');
+
+const encodeLength = require('./length');
+
+module.exports = function encodeU8a (encoder: EncodeFunc, input: Uint8Array): Uint8Array {
+  if (input.length === 1 && input[0] < 128) {
+    return input;
+  }
+
+  return u8aConcat([
+    encodeLength(input.length, 128),
+    input
+  ]);
+};
diff --git a/packages/util-rlp/src/index.js b/packages/util-rlp/src/index.js
new file mode 100644
index 000000000..46d3b3a9c
--- /dev/null
+++ b/packages/util-rlp/src/index.js
@@ -0,0 +1,15 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+const decode = require('./decode');
+const encode = require('./encode');
+
+/**
+  @summary Utility methods to encode and decode [Ethereum RLP](https://github.com/ethereum/wiki/wiki/RLP). Adapted from the [EthereumJS implementation](https://github.com/ethereumjs/rlp/blob/0ce09db81fc303fcee593f7cc094ba44015f9b92/index.js)
+*/
+module.exports = {
+  decode,
+  encode
+};
diff --git a/packages/util-rlp/test/getTests.js b/packages/util-rlp/test/getTests.js
new file mode 100644
index 000000000..41e4ac2b8
--- /dev/null
+++ b/packages/util-rlp/test/getTests.js
@@ -0,0 +1,20 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+
+const BN = require('bn.js');
+const { getSingleFile } = require('ethereumjs-testing');
+
+const bnToU8a = require('@polkadot/util/bn/toU8a');
+
+module.exports = function getTests (file) {
+  const tests = getSingleFile(file);
+
+  return Object.keys(tests).map((name) => ({
+    name,
+    input: tests[name].in[0] !== '#'
+      ? tests[name].in
+      : bnToU8a(new BN(tests[name].in.slice(1))),
+    output: `0x${tests[name].out.toLowerCase()}`
+  }));
+};
diff --git a/packages/util-triehash/docs/README.md b/packages/util-triehash/docs/README.md
index 5a81b31ba..ed22f7387 100644
--- a/packages/util-triehash/docs/README.md
+++ b/packages/util-triehash/docs/README.md
@@ -2,7 +2,6 @@
 
 Utility methods to create [Ethereum Trie hashes](https://github.com/ethereum/wiki/wiki/Patricia-Tree) 
 
-- [util](util.md) Internal utilities used along with hash generation
 
 # Available methods
 
@@ -32,7 +31,7 @@ v: u8aFromString('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa')
 Creates a trie hash from the supplied values. 
 
 ```js
-trieRootOrdered (pvalues: Array<Uint8Array>): Uint8Array
+trieRootOrdered (values: Array<Uint8Array>): Uint8Array
 ```
 
 
diff --git a/packages/util-triehash/docs/util.md b/packages/util-triehash/docs/util.md
deleted file mode 100644
index 5d97e62e5..000000000
--- a/packages/util-triehash/docs/util.md
+++ /dev/null
@@ -1,22 +0,0 @@
-# util
-
-Internal utilities used along with hash generation 
-
-- [asNibbles](#asnibbles) Converts the input to Nibbles.
-
-## asNibbles
-
-Converts the input to Nibbles. 
-
-```js
-asNibbles (pairs: Trie$Pairs): Uint8Array
-```
-
-
-From an `Uint8Array` input, calculate and return a list of nibbles that makes up the input.
-
-```js
-import { asNibbles } from '@polkadot/util-triehash/util';
-
-asNibbles(new Uint8Array([0x41, 0x20]) // => Uint8Array([4, 1, 2, 0])
-```
\ No newline at end of file
diff --git a/packages/util-triehash/package.json b/packages/util-triehash/package.json
index e40d2c47e..441f6afbd 100644
--- a/packages/util-triehash/package.json
+++ b/packages/util-triehash/package.json
@@ -31,7 +31,7 @@
   "dependencies": {
     "@polkadot/util": "^0.14.1",
     "@polkadot/util-crypto": "^0.14.1",
-    "babel-runtime": "^6.26.0",
-    "rlp": "jacogr/rlp"
+    "@polkadot/util-rlp": "^0.14.1",
+    "babel-runtime": "^6.26.0"
   }
 }
diff --git a/packages/util-triehash/src/rootOrdered.js b/packages/util-triehash/src/rootOrdered.js
index 131e69a66..658fd7520 100644
--- a/packages/util-triehash/src/rootOrdered.js
+++ b/packages/util-triehash/src/rootOrdered.js
@@ -2,8 +2,7 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-const bufferToU8a = require('@polkadot/util/buffer/toU8a');
-const rlp = require('rlp');
+const rlpEncode = require('@polkadot/util-rlp/encode');
 
 const asNibbles = require('./util/asNibbles');
 const genRoot = require('./util/genRoot');
@@ -11,7 +10,7 @@ const pairsUniq = require('./util/pairsUniq');
 
 /**
   @name trieRootOrdered
-  @signature trieRootOrdered (pvalues: Array<Uint8Array>): Uint8Array
+  @signature trieRootOrdered (values: Array<Uint8Array>): Uint8Array
   @summary Creates a trie hash from the supplied values.
   @description
     From an `Array<Uint8Array>` input, calculate the ordered triehash and return the result as a `Uint8Array`.
@@ -29,10 +28,7 @@ module.exports = function trieRootOrdered (values: Array<Uint8Array>): Uint8Arra
     pairsUniq(
       values.map((v, index) => ({
         k: asNibbles(
-          bufferToU8a(
-            // $FlowFixMe rlp type definition is lacking
-            rlp.encode(index)
-          )
+          rlpEncode(index)
         ),
         v
       }))
diff --git a/packages/util-triehash/src/util/.nodoc b/packages/util-triehash/src/util/.nodoc
new file mode 100644
index 000000000..e69de29bb
diff --git a/packages/util-triehash/src/util/encode.js b/packages/util-triehash/src/util/encode.js
index c9c7cfa2e..a0a416c73 100644
--- a/packages/util-triehash/src/util/encode.js
+++ b/packages/util-triehash/src/util/encode.js
@@ -6,7 +6,7 @@
 import type { Trie$Pairs } from '../types';
 
 const keccakAsU8a = require('@polkadot/util-crypto/keccak/asU8a');
-const rlp = require('rlp');
+const rlpEncode = require('@polkadot/util-rlp/encode');
 
 const encodeHexPrefix = require('./encodeHexPrefix');
 const sharedPrefixLength = require('./sharedPrefixLength');
@@ -14,8 +14,7 @@ const sharedPrefixLength = require('./sharedPrefixLength');
 // flowlint-next-line unclear-type:off
 function encodeAux (pairs: Trie$Pairs, preLength: number): any {
   const encoded = encode(pairs, preLength);
-  // flowlint-next-line unclear-type:off
-  const rlped = rlp.encode((encoded: any));
+  const rlped = rlpEncode(encoded);
 
   if (rlped.length <= 31) {
     return encoded;
diff --git a/packages/util-triehash/src/util/genRoot.js b/packages/util-triehash/src/util/genRoot.js
index d3ee5baaa..469dd505c 100644
--- a/packages/util-triehash/src/util/genRoot.js
+++ b/packages/util-triehash/src/util/genRoot.js
@@ -6,14 +6,13 @@
 import type { Trie$Pairs } from '../types';
 
 const keccakAsU8a = require('@polkadot/util-crypto/keccak/asU8a');
-const rlp = require('rlp');
+const rlpEncode = require('@polkadot/util-rlp/encode');
 
 const encode = require('./encode');
 
 module.exports = function genRoot (pairs: Trie$Pairs): Uint8Array {
   return keccakAsU8a(
-    rlp.encode(
-      // $FlowFixMe rlp definition is not 100%
+    rlpEncode(
       encode(pairs, 0)
     )
   );
diff --git a/packages/util/docs/bn.md b/packages/util/docs/bn.md
index 96990034c..306e6a005 100644
--- a/packages/util/docs/bn.md
+++ b/packages/util/docs/bn.md
@@ -4,6 +4,7 @@ Utility methods to convert to and from `BN` objects
 
 - [bnFromHex](#bnfromhex) Creates a BN.js bignumber object from a hex string.
 - [bnToHex](#bntohex) Creates a hex value from a BN.js bignumber object.
+- [bnToU8a](#bntou8a) Creates a Uint8Array object from a BN.
 
 ## bnFromHex
 
@@ -33,4 +34,21 @@ import BN from 'bn.js';
 import { bnToHex } from '@polkadot/util';
 
 bnToHex(new BN(0x123456)); // => '0x123456'
+```
+
+## bnToU8a
+
+Creates a Uint8Array object from a BN. 
+
+```js
+bnToU8a (value?: BN): Uint8Array
+```
+
+
+`null`/`undefined`/`NaN` inputs returns an empty `Uint8Array` result. `BN` input values return the actual bytes value converted to a `Uint8Array`.
+
+```js
+import { bnToU8a } from '@polkadot/util';
+
+bnToU8a(new BN(0x1234)); // => [0x12, 0x34]
 ```
\ No newline at end of file
diff --git a/packages/util/docs/number.md b/packages/util/docs/number.md
index 1997177d3..0fb715468 100644
--- a/packages/util/docs/number.md
+++ b/packages/util/docs/number.md
@@ -6,6 +6,7 @@ Utility methods to convert to and from `number` values
 - [numberFromHex](#numberfromhex) Creates a Number value from a Buffer object.
 - [numberToBuffer](#numbertobuffer) Creates a Buffer object from a number.
 - [numberToHex](#numbertohex) Creates a hex value from a number.
+- [numberToU8a](#numbertou8a) Creates a Uint8Array object from a number.
 
 ## numberFromBuffer
 
@@ -63,4 +64,21 @@ numberToHex (value?: number): string
 import { numberToHex } from '@polkadot/util';
 
 const hex = numberToHex(0x1234); // => '0x1234'
+```
+
+## numberToU8a
+
+Creates a Uint8Array object from a number. 
+
+```js
+numberToBuffer (value?: number): Uint8Array
+```
+
+
+`null`/`undefined`/`NaN` inputs returns an empty `Uint8Array` result. `number` input values return the actual bytes value converted to a `Uint8Array`.
+
+```js
+import { numberToU8a } from '@polkadot/util';
+
+numberToU8a(0x1234); // => [0x12, 0x34]
 ```
\ No newline at end of file
diff --git a/packages/util/docs/u8a.md b/packages/util/docs/u8a.md
index 649a36146..dd0053d48 100644
--- a/packages/util/docs/u8a.md
+++ b/packages/util/docs/u8a.md
@@ -2,6 +2,8 @@
 
 Utility methods to convert to and from `Uint8Array` objects 
 
+- [u8aConcat](#u8aconcat) Creates a concatenated Uint8Array from the inputs.
+- [u8aFromBn](#u8afrombn) Creates a Uint8Array value from a BN object.
 - [u8aFromBuffer](#u8afrombuffer) Creates a Uint8Array value from a Buffer object.
 - [u8aFromHex](#u8afromhex) Creates a Uint8Array value from a hex string.
 - [u8aFromString](#u8afromstring) Creates a Uint8Array object from a string.
@@ -10,6 +12,38 @@ Utility methods to convert to and from `Uint8Array` objects
 - [u8aToHex](#u8atohex) Creates a hex string from a Uint8Array object.
 - [u8aToUtf8](#u8atoutf8) Creates a utf-8 string from a Uint8Array object.
 
+## u8aConcat
+
+Creates a concatenated Uint8Array from the inputs. 
+
+```js
+u8aConcat (values: Array<Uint8Array>): Uint8Array
+```
+
+
+Concatenates the input arrays into a single `UInt8Array`.
+
+```js
+import { u8aConcat } from '@polkadot/util';
+
+u8aConcat([
+new Uint8Array([1, 2, 3]),
+new Uint8Array([4, 5, 6])
+]); // [1, 2, 3, 4, 5, 6]
+```
+
+## u8aFromBn
+
+Creates a Uint8Array value from a BN object. [(alias of bnToU8a)](bn.md#bntou8a)
+
+```js
+u8aFromBn (value?: BN): Uint8Array
+```
+
+
+
+
+
 ## u8aFromBuffer
 
 Creates a Uint8Array value from a Buffer object. [(alias of bufferToU8a)](buffer.md#buffertou8a)
diff --git a/packages/util/src/bn/index.js b/packages/util/src/bn/index.js
index d368ffab1..0acf9a9b5 100644
--- a/packages/util/src/bn/index.js
+++ b/packages/util/src/bn/index.js
@@ -5,11 +5,13 @@
 
 const bnFromHex = require('./fromHex');
 const bnToHex = require('./toHex');
+const bnToU8a = require('./toU8a');
 
 /**
   @summary Utility methods to convert to and from `BN` objects
 */
 module.exports = {
   bnFromHex,
-  bnToHex
+  bnToHex,
+  bnToU8a
 };
diff --git a/packages/util/src/bn/toU8a.js b/packages/util/src/bn/toU8a.js
new file mode 100644
index 000000000..365800d48
--- /dev/null
+++ b/packages/util/src/bn/toU8a.js
@@ -0,0 +1,26 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type BN from 'bn.js';
+
+/**
+  @name bnToU8a
+  @signature bnToU8a (value?: BN): Uint8Array
+  @summary Creates a Uint8Array object from a BN.
+  @description
+    `null`/`undefined`/`NaN` inputs returns an empty `Uint8Array` result. `BN` input values return the actual bytes value converted to a `Uint8Array`.
+  @example
+    import { bnToU8a } from '@polkadot/util';
+
+    bnToU8a(new BN(0x1234)); // => [0x12, 0x34]
+*/
+module.exports = function bnToU8a (value?: BN): Uint8Array {
+  if (!value) {
+    return new Uint8Array([]);
+  }
+
+  // $FlowFixMe toArray doesn't need params
+  return new Uint8Array(value.toArray());
+};
diff --git a/packages/util/src/bn/toU8a.spec.js b/packages/util/src/bn/toU8a.spec.js
new file mode 100644
index 000000000..ff8caf9fd
--- /dev/null
+++ b/packages/util/src/bn/toU8a.spec.js
@@ -0,0 +1,21 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+
+const BN = require('bn.js');
+
+const { bnToU8a } = require('./index');
+
+describe('bnToU8a', () => {
+  it('converts BN values to a prefixed hex representation', () => {
+    expect(
+      bnToU8a(new BN(0x123456))
+    ).toEqual(new Uint8Array([0x12, 0x34, 0x56]));
+  });
+
+  it('converts null values to 0x00', () => {
+    expect(
+      bnToU8a(null)
+    ).toEqual(new Uint8Array([]));
+  });
+});
diff --git a/packages/util/src/buffer/toU8a.js b/packages/util/src/buffer/toU8a.js
index 9c0ae0525..b6a722412 100644
--- a/packages/util/src/buffer/toU8a.js
+++ b/packages/util/src/buffer/toU8a.js
@@ -19,11 +19,5 @@ module.exports = function bufferToU8a (buffer?: Buffer): Uint8Array {
     return new Uint8Array([]);
   }
 
-  const array = new Uint8Array(buffer.length);
-
-  for (let index = 0; index < buffer.length; ++index) {
-    array[index] = buffer[index];
-  }
-
-  return array;
+  return new Uint8Array(buffer);
 };
diff --git a/packages/util/src/number/index.js b/packages/util/src/number/index.js
index 61ac84aed..310f1ddac 100644
--- a/packages/util/src/number/index.js
+++ b/packages/util/src/number/index.js
@@ -7,6 +7,7 @@ const numberFromBuffer = require('./fromBuffer');
 const numberFromHex = require('./fromHex');
 const numberToBuffer = require('./toBuffer');
 const numberToHex = require('./toHex');
+const numberToU8a = require('./toU8a');
 
 /**
   @summary Utility methods to convert to and from `number` values
@@ -15,5 +16,6 @@ module.exports = {
   numberFromBuffer,
   numberFromHex,
   numberToBuffer,
-  numberToHex
+  numberToHex,
+  numberToU8a
 };
diff --git a/packages/util/src/number/toU8a.js b/packages/util/src/number/toU8a.js
new file mode 100644
index 000000000..27aff0e67
--- /dev/null
+++ b/packages/util/src/number/toU8a.js
@@ -0,0 +1,29 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+const hexToU8a = require('../hex/toU8a');
+const numberToHex = require('./toHex');
+
+/**
+  @name numberToU8a
+  @signature numberToBuffer (value?: number): Uint8Array
+  @summary Creates a Uint8Array object from a number.
+  @description
+    `null`/`undefined`/`NaN` inputs returns an empty `Uint8Array` result. `number` input values return the actual bytes value converted to a `Uint8Array`.
+  @example
+    import { numberToU8a } from '@polkadot/util';
+
+    numberToU8a(0x1234); // => [0x12, 0x34]
+*/
+module.exports = function numberToU8a (value?: number): Uint8Array {
+  // flowlint-next-line sketchy-null-number:off
+  if (!value || isNaN(value)) {
+    return new Uint8Array([]);
+  }
+
+  return hexToU8a(
+    numberToHex(value)
+  );
+};
diff --git a/packages/util/src/number/toU8a.spec.js b/packages/util/src/number/toU8a.spec.js
new file mode 100644
index 000000000..6c1638e57
--- /dev/null
+++ b/packages/util/src/number/toU8a.spec.js
@@ -0,0 +1,37 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+
+const { numberToU8a } = require('./index');
+
+describe('numberToU8a', () => {
+  it('converts 0 to empty', () => {
+    expect(
+      numberToU8a(0)
+    ).toEqual(new Uint8Array([]));
+  });
+
+  it('converts undefined to empty', () => {
+    expect(
+      numberToU8a()
+    ).toEqual(new Uint8Array([]));
+  });
+
+  it('converts null to empty', () => {
+    expect(
+      numberToU8a(null)
+    ).toEqual(new Uint8Array([]));
+  });
+
+  it('converts NaN to empty', () => {
+    expect(
+      numberToU8a(NaN)
+    ).toEqual(new Uint8Array([]));
+  });
+
+  it('converts values to the buffer', () => {
+    expect(
+      numberToU8a(0x3456)
+    ).toEqual(new Uint8Array([0x34, 0x56]));
+  });
+});
diff --git a/packages/util/src/u8a/concat.js b/packages/util/src/u8a/concat.js
new file mode 100644
index 000000000..5f9400c7c
--- /dev/null
+++ b/packages/util/src/u8a/concat.js
@@ -0,0 +1,30 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+/**
+  @name u8aConcat
+  @signature u8aConcat (values: Array<Uint8Array>): Uint8Array
+  @summary Creates a concatenated Uint8Array from the inputs.
+  @description
+    Concatenates the input arrays into a single `UInt8Array`.
+  @example
+    import { u8aConcat } from '@polkadot/util';
+
+    u8aConcat([
+      new Uint8Array([1, 2, 3]),
+      new Uint8Array([4, 5, 6])
+    ]); // [1, 2, 3, 4, 5, 6]
+*/
+module.exports = function u8aConcat (list: Array<Uint8Array>): Uint8Array {
+  const length = list.reduce((total, item) => total + item.length, 0);
+  let offset = 0;
+
+  return list.reduce((result, item) => {
+    result.set(item, offset);
+    offset += item.length;
+
+    return result;
+  }, new Uint8Array(length));
+};
diff --git a/packages/util/src/u8a/concat.spec.js b/packages/util/src/u8a/concat.spec.js
new file mode 100644
index 000000000..569351979
--- /dev/null
+++ b/packages/util/src/u8a/concat.spec.js
@@ -0,0 +1,19 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+
+const { u8aConcat } = require('./index');
+
+describe('u8aConcat', () => {
+  it('concatenates arrays', () => {
+    expect(
+      u8aConcat([
+        new Uint8Array([1, 2, 3, 4]),
+        new Uint8Array([5, 6]),
+        new Uint8Array([7, 8, 9])
+      ])
+    ).toEqual(
+      new Uint8Array([1, 2, 3, 4, 5, 6, 7, 8, 9])
+    );
+  });
+});
diff --git a/packages/util/src/u8a/fromBn.js b/packages/util/src/u8a/fromBn.js
new file mode 100644
index 000000000..cf28091fa
--- /dev/null
+++ b/packages/util/src/u8a/fromBn.js
@@ -0,0 +1,14 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+const u8aFromBn = require('../bn/toU8a');
+
+/**
+  @name u8aFromBn
+  @signature u8aFromBn (value?: BN): Uint8Array
+  @summary Creates a Uint8Array value from a BN object.
+  @alias bn/toU8a
+*/
+module.exports = u8aFromBn;
diff --git a/packages/util/src/u8a/fromBn.spec.js b/packages/util/src/u8a/fromBn.spec.js
new file mode 100644
index 000000000..30e6a9e7b
--- /dev/null
+++ b/packages/util/src/u8a/fromBn.spec.js
@@ -0,0 +1,15 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+
+const isFunction = require('../is/function');
+
+const { u8aFromBn } = require('./index');
+
+describe('u8aFromBn', () => {
+  it('exists as a function', () => {
+    expect(
+      isFunction(u8aFromBn)
+    ).toEqual(true);
+  });
+});
diff --git a/packages/util/src/u8a/index.js b/packages/util/src/u8a/index.js
index 3e9ec7030..3f1337ef4 100644
--- a/packages/util/src/u8a/index.js
+++ b/packages/util/src/u8a/index.js
@@ -3,6 +3,8 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
+const u8aConcat = require('./concat');
+const u8aFromBn = require('./fromBn');
 const u8aFromBuffer = require('./fromBuffer');
 const u8aFromHex = require('./fromHex');
 const u8aFromUtf8 = require('./fromUtf8');
@@ -15,6 +17,8 @@ const u8aToUtf8 = require('./toUtf8');
   @summary Utility methods to convert to and from `Uint8Array` objects
 */
 module.exports = {
+  u8aConcat,
+  u8aFromBn,
   u8aFromBuffer,
   u8aFromHex,
   u8aFromString,
diff --git a/yarn.lock b/yarn.lock
index eb45eac43..d418ca19d 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -69,9 +69,9 @@
   dependencies:
     babel-runtime "^6.26.0"
 
-"@polkadot/dev@^0.15.2":
-  version "0.15.2"
-  resolved "https://registry.yarnpkg.com/@polkadot/dev/-/dev-0.15.2.tgz#496350e1ca3dfa30d73bd64206c221fa6e96b3ec"
+"@polkadot/dev@^0.15.6":
+  version "0.15.6"
+  resolved "https://registry.yarnpkg.com/@polkadot/dev/-/dev-0.15.6.tgz#9ca3ec886bc60206851cb2e780723629e53d19f7"
   dependencies:
     babel-cli "^6.26.0"
     babel-core "^6.26.0"
@@ -91,11 +91,11 @@
     eslint-plugin-flowtype "^2.39.1"
     eslint-plugin-import "^2.8.0"
     eslint-plugin-jest "^21.3.2"
-    eslint-plugin-node "^5.2.1"
+    eslint-plugin-node "^6.0.0"
     eslint-plugin-promise "^3.6.0"
     eslint-plugin-react "^7.4.0"
     eslint-plugin-standard "^3.0.1"
-    flow-bin "^0.64.0"
+    flow-bin "^0.65.0"
     flow-copy-source "^1.2.1"
     jest "^22.0.0"
     makeshift "^1.1.0"
@@ -944,12 +944,6 @@ bindings@~1.2.1:
   version "1.2.1"
   resolved "https://registry.yarnpkg.com/bindings/-/bindings-1.2.1.tgz#14ad6113812d2d37d72e67b4cacb4bb726505f11"
 
-bl@^1.0.0:
-  version "1.2.1"
-  resolved "https://registry.yarnpkg.com/bl/-/bl-1.2.1.tgz#cac328f7bee45730d404b692203fcb590e172d5e"
-  dependencies:
-    readable-stream "^2.0.5"
-
 blakejs@^1.1.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/blakejs/-/blakejs-1.1.0.tgz#69df92ef953aa88ca51a32df6ab1c54a155fc7a5"
@@ -1141,10 +1135,6 @@ chokidar@^1.6.1, chokidar@^1.7.0:
   optionalDependencies:
     fsevents "^1.0.0"
 
-chownr@^1.0.1:
-  version "1.0.1"
-  resolved "https://registry.yarnpkg.com/chownr/-/chownr-1.0.1.tgz#e2a75042a9551908bebd25b8523d5f9769d79181"
-
 ci-info@^1.0.0:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/ci-info/-/ci-info-1.1.2.tgz#03561259db48d0474c8bdc90f5b47b068b6bbfb4"
@@ -1714,12 +1704,6 @@ encoding@^0.1.11:
   dependencies:
     iconv-lite "~0.4.13"
 
-end-of-stream@^1.0.0, end-of-stream@^1.1.0:
-  version "1.4.0"
-  resolved "https://registry.yarnpkg.com/end-of-stream/-/end-of-stream-1.4.0.tgz#7a90d833efda6cfa6eac0f4949dbb0fad3a63206"
-  dependencies:
-    once "^1.4.0"
-
 entities@^1.1.1, entities@~1.1.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/entities/-/entities-1.1.1.tgz#6e5c2d0a5621b5dadaecef80b90edfb5cd7772f0"
@@ -1820,14 +1804,14 @@ eslint-plugin-jest@^21.3.2:
   version "21.3.2"
   resolved "https://registry.yarnpkg.com/eslint-plugin-jest/-/eslint-plugin-jest-21.3.2.tgz#b1cefc05f0fed700eb40185a94d16f6d575d1ef9"
 
-eslint-plugin-node@^5.2.1:
-  version "5.2.1"
-  resolved "https://registry.yarnpkg.com/eslint-plugin-node/-/eslint-plugin-node-5.2.1.tgz#80df3253c4d7901045ec87fa660a284e32bdca29"
+eslint-plugin-node@^6.0.0:
+  version "6.0.0"
+  resolved "https://registry.yarnpkg.com/eslint-plugin-node/-/eslint-plugin-node-6.0.0.tgz#5ad5ee6b5346aec6cc9cde0b8619caed2c6d8f25"
   dependencies:
     ignore "^3.3.6"
     minimatch "^3.0.4"
     resolve "^1.3.3"
-    semver "5.3.0"
+    semver "^5.4.1"
 
 eslint-plugin-promise@^3.6.0:
   version "3.6.0"
@@ -1935,6 +1919,12 @@ esutils@^2.0.2:
   version "2.0.2"
   resolved "https://registry.yarnpkg.com/esutils/-/esutils-2.0.2.tgz#0abf4f1caa5bcb1f7a9d8acc6dea4faaa04bac9b"
 
+ethereumjs-testing@^1.0.4:
+  version "1.0.4"
+  resolved "https://registry.yarnpkg.com/ethereumjs-testing/-/ethereumjs-testing-1.0.4.tgz#8739f4104e9838ba92f3060eeb165c581041251d"
+  dependencies:
+    node-dir "^0.1.16"
+
 exec-sh@^0.2.0:
   version "0.2.1"
   resolved "https://registry.yarnpkg.com/exec-sh/-/exec-sh-0.2.1.tgz#163b98a6e89e6b65b47c2a28d215bc1f63989c38"
@@ -1983,10 +1973,6 @@ expand-range@^1.8.1:
   dependencies:
     fill-range "^2.1.0"
 
-expand-template@^1.0.2:
-  version "1.1.0"
-  resolved "https://registry.yarnpkg.com/expand-template/-/expand-template-1.1.0.tgz#e09efba977bf98f9ee0ed25abd0c692e02aec3fc"
-
 expect@^22.0.3:
   version "22.0.3"
   resolved "https://registry.yarnpkg.com/expect/-/expect-22.0.3.tgz#bb486de7d41bf3eb60d3b16dfd1c158a4d91ddfa"
@@ -2106,9 +2092,9 @@ flat-cache@^1.2.1:
     graceful-fs "^4.1.2"
     write "^0.2.1"
 
-flow-bin@^0.64.0:
-  version "0.64.0"
-  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.64.0.tgz#ddd3fb3b183ab1ab35a5d5dec9caf5ebbcded167"
+flow-bin@^0.65.0:
+  version "0.65.0"
+  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.65.0.tgz#64ffeca27211c786e2d68508c65686ba1b8a2169"
 
 flow-copy-source@^1.2.1:
   version "1.2.1"
@@ -2289,10 +2275,6 @@ gitconfiglocal@^1.0.0:
   dependencies:
     ini "^1.3.2"
 
-github-from-package@0.0.0:
-  version "0.0.0"
-  resolved "https://registry.yarnpkg.com/github-from-package/-/github-from-package-0.0.0.tgz#97fb5d96bfde8973313f20e8288ef9a167fa64ce"
-
 glob-base@^0.3.0:
   version "0.3.0"
   resolved "https://registry.yarnpkg.com/glob-base/-/glob-base-0.3.0.tgz#dbb164f6221b1c0b1ccf82aea328b497df0ea3c4"
@@ -3288,14 +3270,13 @@ jsx-ast-utils@^2.0.0:
   dependencies:
     array-includes "^3.0.3"
 
-keccak@^1.3.0:
-  version "1.3.0"
-  resolved "https://registry.yarnpkg.com/keccak/-/keccak-1.3.0.tgz#3681bd99ad3d0354ddb29b9040c1b6560cce08ac"
+keccak@jacogr/keccak#f25ae4b299038bb2f0b72f150b99b5048ffb9e48:
+  version "1.4.0"
+  resolved "https://codeload.github.com/jacogr/keccak/tar.gz/f25ae4b299038bb2f0b72f150b99b5048ffb9e48"
   dependencies:
     bindings "^1.2.1"
     inherits "^2.0.3"
     nan "^2.2.1"
-    prebuild-install "^2.0.0"
     safe-buffer "^5.1.0"
 
 kefir@^3.7.3:
@@ -3687,11 +3668,11 @@ natural-compare@^1.4.0:
   version "1.4.0"
   resolved "https://registry.yarnpkg.com/natural-compare/-/natural-compare-1.4.0.tgz#4abebfeed7541f2c27acfb29bdbbd15c8d5ba4f7"
 
-node-abi@^2.1.1:
-  version "2.1.2"
-  resolved "https://registry.yarnpkg.com/node-abi/-/node-abi-2.1.2.tgz#4da6caceb6685fcd31e7dd1994ef6bb7d0a9c0b2"
+node-dir@^0.1.16:
+  version "0.1.17"
+  resolved "https://registry.yarnpkg.com/node-dir/-/node-dir-0.1.17.tgz#5f5665d93351335caabef8f1c554516cf5f1e4e5"
   dependencies:
-    semver "^5.4.1"
+    minimatch "^3.0.2"
 
 node-fetch@^1.0.1:
   version "1.7.3"
@@ -3729,10 +3710,6 @@ node-pre-gyp@^0.6.39:
     tar "^2.2.1"
     tar-pack "^3.4.0"
 
-noop-logger@^0.1.1:
-  version "0.1.1"
-  resolved "https://registry.yarnpkg.com/noop-logger/-/noop-logger-0.1.1.tgz#94a2b1633c4f1317553007d8966fd0e841b6a4c2"
-
 nopt@^4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/nopt/-/nopt-4.0.1.tgz#d0d4685afd5415193c8c7505602d0d17cd64474d"
@@ -3769,7 +3746,7 @@ npm-run-path@^2.0.0:
   dependencies:
     path-key "^2.0.0"
 
-npmlog@^4.0.1, npmlog@^4.0.2, npmlog@^4.1.2:
+npmlog@^4.0.2, npmlog@^4.1.2:
   version "4.1.2"
   resolved "https://registry.yarnpkg.com/npmlog/-/npmlog-4.1.2.tgz#08a7f2a8bf734604779a9efa4ad5cc717abb954b"
   dependencies:
@@ -3816,7 +3793,7 @@ object.omit@^2.0.0:
     for-own "^0.1.4"
     is-extendable "^0.1.1"
 
-once@^1.3.0, once@^1.3.1, once@^1.3.3, once@^1.4.0:
+once@^1.3.0, once@^1.3.3, once@^1.4.0:
   version "1.4.0"
   resolved "https://registry.yarnpkg.com/once/-/once-1.4.0.tgz#583b1aa775961d4b113ac17d9c50baef9dd76bd1"
   dependencies:
@@ -3846,7 +3823,7 @@ optionator@^0.8.1, optionator@^0.8.2:
     type-check "~0.3.2"
     wordwrap "~1.0.0"
 
-os-homedir@^1.0.0, os-homedir@^1.0.1:
+os-homedir@^1.0.0:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/os-homedir/-/os-homedir-1.0.2.tgz#ffbc4988336e0e833de0c168c7ef152121aa7fb3"
 
@@ -4126,25 +4103,6 @@ postcss@^6.0.16:
     source-map "^0.6.1"
     supports-color "^5.1.0"
 
-prebuild-install@^2.0.0:
-  version "2.3.0"
-  resolved "https://registry.yarnpkg.com/prebuild-install/-/prebuild-install-2.3.0.tgz#19481247df728b854ab57b187ce234211311b485"
-  dependencies:
-    expand-template "^1.0.2"
-    github-from-package "0.0.0"
-    minimist "^1.2.0"
-    mkdirp "^0.5.1"
-    node-abi "^2.1.1"
-    noop-logger "^0.1.1"
-    npmlog "^4.0.1"
-    os-homedir "^1.0.1"
-    pump "^1.0.1"
-    rc "^1.1.6"
-    simple-get "^1.4.2"
-    tar-fs "^1.13.0"
-    tunnel-agent "^0.6.0"
-    xtend "4.0.1"
-
 prelude-ls@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/prelude-ls/-/prelude-ls-1.1.2.tgz#21932a549f5e52ffd9a827f570e04be62a97da54"
@@ -4194,13 +4152,6 @@ pseudomap@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/pseudomap/-/pseudomap-1.0.2.tgz#f052a28da70e618917ef0a8ac34c1ae5a68286b3"
 
-pump@^1.0.0, pump@^1.0.1:
-  version "1.0.3"
-  resolved "https://registry.yarnpkg.com/pump/-/pump-1.0.3.tgz#5dfe8311c33bbf6fc18261f9f34702c47c08a954"
-  dependencies:
-    end-of-stream "^1.1.0"
-    once "^1.3.1"
-
 punycode@^1.4.1:
   version "1.4.1"
   resolved "https://registry.yarnpkg.com/punycode/-/punycode-1.4.1.tgz#c0d5a63b2718800ad8e1eb0fa5269c84dd41845e"
@@ -4290,7 +4241,7 @@ read-pkg@^3.0.0:
     normalize-package-data "^2.3.2"
     path-type "^3.0.0"
 
-readable-stream@^2.0.0, readable-stream@^2.0.1, readable-stream@^2.0.2, readable-stream@^2.0.5, readable-stream@^2.0.6, readable-stream@^2.1.4, readable-stream@^2.1.5, readable-stream@^2.2.2:
+readable-stream@^2.0.1, readable-stream@^2.0.2, readable-stream@^2.0.6, readable-stream@^2.1.4, readable-stream@^2.1.5, readable-stream@^2.2.2:
   version "2.3.3"
   resolved "https://registry.yarnpkg.com/readable-stream/-/readable-stream-2.3.3.tgz#368f2512d79f9d46fdfc71349ae7878bbc1eb95c"
   dependencies:
@@ -4574,10 +4525,6 @@ rimraf@2, rimraf@^2.2.8, rimraf@^2.5.1, rimraf@^2.5.4, rimraf@^2.6.1, rimraf@^2.
   dependencies:
     glob "^7.0.5"
 
-rlp@jacogr/rlp:
-  version "2.0.0"
-  resolved "https://codeload.github.com/jacogr/rlp/tar.gz/ca33b296fc43d7a3543d8a8f172adc9b66826f5f"
-
 run-async@^2.2.0:
   version "2.3.0"
   resolved "https://registry.yarnpkg.com/run-async/-/run-async-2.3.0.tgz#0371ab4ae0bdd720d4166d7dfda64ff7a445a6c0"
@@ -4620,10 +4567,6 @@ sax@^1.2.1:
   version "5.4.1"
   resolved "https://registry.yarnpkg.com/semver/-/semver-5.4.1.tgz#e059c09d8571f0540823733433505d3a2f00b18e"
 
-semver@5.3.0:
-  version "5.3.0"
-  resolved "https://registry.yarnpkg.com/semver/-/semver-5.3.0.tgz#9b2ce5d3de02d17c6012ad326aa6b4d0cf54f94f"
-
 semver@^5.0.1, semver@^5.1.0:
   version "5.5.0"
   resolved "https://registry.yarnpkg.com/semver/-/semver-5.5.0.tgz#dc4bbc7a6ca9d916dee5d43516f0092b58f7b8ab"
@@ -4658,14 +4601,6 @@ signal-exit@^3.0.0, signal-exit@^3.0.2:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/signal-exit/-/signal-exit-3.0.2.tgz#b5fdc08f1287ea1178628e415e25132b73646c6d"
 
-simple-get@^1.4.2:
-  version "1.4.3"
-  resolved "https://registry.yarnpkg.com/simple-get/-/simple-get-1.4.3.tgz#e9755eda407e96da40c5e5158c9ea37b33becbeb"
-  dependencies:
-    once "^1.3.1"
-    unzip-response "^1.0.0"
-    xtend "^4.0.0"
-
 slash@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/slash/-/slash-1.0.0.tgz#c41f2f6c39fc16d1cd17ad4b5d896114ae470d55"
@@ -4979,15 +4914,6 @@ table@^4.0.1:
     slice-ansi "1.0.0"
     string-width "^2.1.1"
 
-tar-fs@^1.13.0:
-  version "1.16.0"
-  resolved "https://registry.yarnpkg.com/tar-fs/-/tar-fs-1.16.0.tgz#e877a25acbcc51d8c790da1c57c9cf439817b896"
-  dependencies:
-    chownr "^1.0.1"
-    mkdirp "^0.5.1"
-    pump "^1.0.0"
-    tar-stream "^1.1.2"
-
 tar-pack@^3.4.0:
   version "3.4.1"
   resolved "https://registry.yarnpkg.com/tar-pack/-/tar-pack-3.4.1.tgz#e1dbc03a9b9d3ba07e896ad027317eb679a10a1f"
@@ -5001,15 +4927,6 @@ tar-pack@^3.4.0:
     tar "^2.2.1"
     uid-number "^0.0.6"
 
-tar-stream@^1.1.2:
-  version "1.5.5"
-  resolved "https://registry.yarnpkg.com/tar-stream/-/tar-stream-1.5.5.tgz#5cad84779f45c83b1f2508d96b09d88c7218af55"
-  dependencies:
-    bl "^1.0.0"
-    end-of-stream "^1.0.0"
-    readable-stream "^2.0.0"
-    xtend "^4.0.0"
-
 tar@^2.2.1:
   version "2.2.1"
   resolved "https://registry.yarnpkg.com/tar/-/tar-2.2.1.tgz#8e4d2a256c0e2185c6b18ad694aec968b83cb1d1"
@@ -5243,10 +5160,6 @@ universalify@^0.1.0:
   version "0.1.1"
   resolved "https://registry.yarnpkg.com/universalify/-/universalify-0.1.1.tgz#fa71badd4437af4c148841e3b3b165f9e9e590b7"
 
-unzip-response@^1.0.0:
-  version "1.0.2"
-  resolved "https://registry.yarnpkg.com/unzip-response/-/unzip-response-1.0.2.tgz#b984f0877fc0a89c2c773cc1ef7b5b232b5b06fe"
-
 unzip-response@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/unzip-response/-/unzip-response-2.0.1.tgz#d2f0f737d16b0615e72a6935ed04214572d56f97"
@@ -5463,7 +5376,7 @@ xml-name-validator@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/xml-name-validator/-/xml-name-validator-2.0.1.tgz#4d8b8f1eccd3419aa362061becef515e1e559635"
 
-xtend@4.0.1, xtend@^4.0.0, xtend@^4.0.1, xtend@~4.0.1:
+xtend@^4.0.1, xtend@~4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/xtend/-/xtend-4.0.1.tgz#a5c6d532be656e23db820efb943a1f04998d63af"