zymoo / node-seal

Homomorphic Encryption in JavaScript - Microsoft SEAL

node-seal ·

node-seal is a homomorphic encryption library in JavaScript.

• Web Assembly: Fastest web implementation of the C++ Microsoft SEAL library
• Zero dependencies: Very lean, only contains a low level API which is very close to the C++ calls from Microsoft SEAL.
• Node.js or the browser: Install once, work in any server/client configuration.

Now supporting Microsoft SEAL 3.5.8

Installation

node-seal can be installed with your favorite package manager:

npm install node-seal

yarn add node-seal

Import the library using import or require syntax:

// Auto-detects browser or nodejs.
// Defaults to use the WASM build which throws on transparent ciphertexts
import { Seal } from 'node-seal'
const { Seal } = require('node-seal')

Specify a target environment. This is useful for environments that aren't detected properly or do not support WebAssembly. In addition, there are two separate bundles for throwing on transparent ciphertexts and another for allowing transparent ciphertexts. If you're unsure what you need, start with the build that throws on transparent ciphertexts. This is also the default import that is used.

// Pick one that suits your need (throws on transparent ciphertexts)
import { Seal } from 'node-seal/dist/throws_transparent/node/wasm' // Specifies the WASM build for NodeJS
import { Seal } from 'node-seal/dist/throws_transparent/node/js' // Specifies the JS build for NodeJS
import { Seal } from 'node-seal/dist/throws_transparent/web/wasm' // Specifies the WASM build for the browser
import { Seal } from 'node-seal/dist/throws_transparent/web/js' // Specifies the JS build for the browser

// Pick one that suits your need (allows transparent ciphertexts)
import { Seal } from 'node-seal/dist/allows_transparent/node/wasm' // Specifies the WASM build for NodeJS
import { Seal } from 'node-seal/dist/allows_transparent/node/js' // Specifies the JS build for NodeJS
import { Seal } from 'node-seal/dist/allows_transparent/web/wasm' // Specifies the WASM build for the browser
import { Seal } from 'node-seal/dist/allows_transparent/web/js' // Specifies the JS build for the browser

React-Native

In react-native environments, there are two ways of using node-seal.

1. Load the pure JS build
2. Create a WebView and manage node-seal inside.

Option 1 is the easiest method, but performance is significantly reduced. Because emscripten expects either a NodeJS or Web environment, loading node-seal will fail because it expects a browser global object that doesn't not exist. The solution is to spoof the document object.

Simply add an empty document object to the global provided by react-native:

import { Seal } from 'node-seal/dist/throws_transparent/web/js'
;(async () => {
  global.document = {} // mimic browser document
  const seal = await Seal()
})()

Option 2 is harder to implement, but it will allow you to use the faster dist/throws_transparent/web/wasm build. The implementation will need to manage the state within the WebView.

Demo

Go to morfix.io/sandbox

This sandbox was built for users to experiment and learn how to use Microsoft SEAL featuring node-seal.

• Encryption Parameters: experiment with many settings to prototype a context.
• Keys: Create, download, upload Secret/Public Keys - even for Relinearization and Galois Keys.
• Variables: Create, download, upload PlainTexts or CipherTexts
• Functions: Create a list of HE functions to execute!
• Code Generation: After your experimentation is complete, generate working code to use!

Usage

Checkout the basics

Documentation

View the latest docs here

Examples

Check out the Sandbox to run HE functions and even generate working code!

If you'd rather read an example, take a look here.

For more exhaustive examples, view the tests or the benchmarks.

Changes

For changes in this library, take a look here.

For changes in Microsoft SEAL, take a look at their list of changes.

Benchmarks

A set of benchmarks similar to the benchmarks of the native SEAL C++ code can be found here.

Run them by cloning this repository and then run npm run benchmark:bfv or npm run benchmark:ckks.

The scripts are only for NodeJS. We have adapted a variant of this script for each browser and have shown the results in the section below.

Performance

Test specs 2018 MacBook Pro:

• 2.6 GHz 6-Core Intel Core i7
• 16 GB 2400 MHz DDR4

Versions:

• Microsoft Seal v3.4.5
• Node-seal v4.1.4
• NodeJS v12.16.1
• Chrome Version 80.0.3987.149 (Official Build) (64-bit)
• Firefox 74.0 (64-bit)
• Safari Version 13.0.5 (15608.5.11)

Encryption Parameters:

• Scheme: BFV
• Poly Modulus Degree: 16384
• Coeff Modulus Size: 438 (48 + 48 + 48 + 49 + 49 + 49 + 49 + 49 + 49) bits
• Plain Modulus: 786433

Number of iterations is 100, time in microseconds. Browser timers are known to be imprecise, variance maybe high.

16384, n = 100	Node.js	Chrome	Firefox	Safari	Seal (C++)	Node.js (times slower)	Chrome (times slower)	Firefox (times slower)	Safari (times slower)
KeyPair	36422	32770	29000	55000	22376	1.63	1.46	1.30	2.46
RelinKeys	230859	197870	198000	175000	138788	1.66	1.43	1.43	1.26
GaloisKeys	5937772	5084275	4936000	4624000	3577623	1.66	1.42	1.38	1.29
Batch	868	752	670	767	327	2.65	2.30	2.05	2.35
Unbatch	1026	926	730	1467	304	3.38	3.05	2.40	4.83
Encrypt	46826	41455	37110	34800	18712	2.50	2.22	1.98	1.86
Decrypt	20992	19078	16460	15667	6134	3.42	3.11	2.68	2.55
Add	1404	1185	447	389	212	6.62	5.59	2.11	1.83
Multiply	245425	231089	209040	204700	60896	4.03	3.79	3.43	3.36
Multiply Plain	35541	31305	24260	22367	10318	3.44	3.03	2.35	2.17
Square	180152	169122	155860	148533	45762	3.94	3.70	3.41	3.25
Relinearize	98158	85478	66870	66333	25139	3.90	3.40	2.66	2.64
Rotate Row One Step	97292	85724	67615	65400	25247	3.85	3.40	2.68	2.59
Rotate Row Random Step	416774	384842	295540	285733	118948	3.50	3.24	2.48	2.40
Rotate Column	97366	85515	67730	64567	25274	3.85	3.38	2.68	2.55

Caveats

Conversion from C++ to Web Assembly has some limitations:

• ±2^53 bit numbers: JavaScript uses 2^53 numbers (not true 64 bit). Values higher than these will typically result in inaccuracies. BFV users will inherently adhere to these limitations due to the Int32/UInt32 TypedArrays. CKKS users will need to keep this in mind. There are extra methods that now support 64-bit integers using BigInt for BFV at a significant performance penalty. However, CKKS is still limited to 2^53-bit precision.

• Memory: Generating large keys and saving them in the browser could be problematic. We can control NodeJS heap size, but not inside a user's browser.

  Saving keys is very memory intensive especially for polyModulusDegreess above 16384. This is because there's currently no way (that we have found) to use io streams across JS and Web Assembly code, so the strings have to be buffered completely in RAM and they can be very, very large. This holds especially true for GaloisKeys where you may hit JS max string limits (256MB).

• Garbage Collection: Unfortunately, the typical way of cleaning up dereferenced JS objects will leave behind a the Web Assembly (C++) object in memory. There is no way to automatically call the destructors on C++ objects. JavaScript code must explicitly delete any C++ object handles it has received, or the heap will grow indefinitely.

  <instance>.delete()

Contributing

The main purpose of this library is to continue to evolve and promote the adoption of homomorphic encryption (using Microsoft SEAL) in modern web applications today. Development of node-seal happens in the open on GitHub, and we are grateful to the community for contributing bugfixes and improvements.

See CONTRIBUTING.md.

License

node-seal is MIT licensed.