How to hash a file with sha256 in Ionic 4 app based on Angular 7?

Question

I am trying to hash a file more than 1GB using SHA256 in an Ionic 4 app based on Angular 7. I want to use this NPM module. But there is no documentation. How and where to import this module? or suggest a better alternative.

Following error I am getting: enter image description here

I have tried: import * as sha256File from 'sha256-file';

This is index.js file: there is no 'crypto' or 'fs' in the folder.

'use strict';

var crypto = require('crypto');
var fs = require('fs');

module.exports = function (filename, callback) {
  var sum = crypto.createHash('sha256');
  if (callback && typeof callback === 'function') {
    var fileStream = fs.createReadStream(filename);
    fileStream.on('error', function (err) {
      return callback(err, null)
    });
    fileStream.on('data', function (chunk) {
      try {
        sum.update(chunk)
      } catch (ex) {
        return callback(ex, null)
      }
    });
    fileStream.on('end', function () {
      return callback(null, sum.digest('hex'))
    })
  } else {
    sum.update(fs.readFileSync(filename));
    return sum.digest('hex')
  }
};

Answer 1

Take a look at Sodium (libsodium.js).

Sodium is a modern, easy-to-use software library for encryption, decryption, signatures, password hashing and more.

It is a portable, cross-compilable, installable, packageable fork of NaCl, with a compatible API, and an extended API to improve usability even further.

Its goal is to provide all of the core operations needed to build higher-level cryptographic tools.

Sodium is cross-platforms and cross-languages. It runs on a variety of compilers and operating systems, including Windows (with MinGW or Visual Studio, x86 and x86_64), iOS and Android. Javascript and WebAssembly versions are also available and are fully supported. Bindings for all common programming languages are available and well-supported.

The design choices emphasize security and ease of use. But despite the emphasis on high security, primitives are faster across-the-board than most implementations.

Version 1.0.17 was released on January 7, 2019.

Ref:

• Sodium GitBook
• List of awesome JavaScript Crypto Libraries
• JavaScript Crypto Libraries

Answer 2

You should post code you've tried in any questions, but based on this particular package, you probably just need to install it and do something like:

import * as sha256File from 'sha256-file';

then usage is simple according to the docs:

const sum = sha256File('./path/to/a_file');

Answer 3

Finally I solved the problem. Thank you everyone for suggesting me the solutions. In my solution I user 'crypto-js' library. I import it as:

import * as crypto from 'crypto-js';

Then user file reader to read file as below:

const reader = new FileReader();
    reader.onloadend = () => {
      const imgBlob = new Blob([reader.result], {
        type: filePath.type
      });
      var file_wordArr = crypto.lib.WordArray.create(imgBlob); //convert blob to WordArray
          var sha256_hash = crypto.SHA256(file_wordArr); //calculate SHA256 hash
          //alert("Calculated SHA1:" + sha256_hash.toString()); 
          console.log(sha256_hash.toString());
}
this.file.resolveLocalFilesystemUrl(filePath) //file path of android system
.then(entry => {
  (<FileEntry>entry).file(file => reader.readAsArrayBuffer(file))
})

I got what I wanted with this code.

Answer 4

You should have a look at the index.js file of the package you are trying to use. It seems like you are missing some packages (namely crypto and fs, which I assume is filesystem). Try installing them with npm