How can I get the sha1 hash of a string in node.js?

Question

I'm trying to create a websocket server written in node.js

To get the server to work I need to get the SHA1 hash of a string.

What I have to do is explained in Section 5.2.2 page 35 of the docs.

NOTE: As an example, if the value of the "Sec-WebSocket-Key" header in the client's handshake were "dGhlIHNhbXBsZSBub25jZQ==", the server would append thestring "258EAFA5-E914-47DA-95CA-C5AB0DC85B11" to form the string "dGhlIHNhbXBsZSBub25jZQ==258EAFA5-E914-47DA-95CA-C5AB0DC85B11". The server would then take the SHA-1 hash of this string, giving the value 0xb3 0x7a 0x4f 0x2c 0xc0 0x62 0x4f 0x16 0x90 0xf6 0x46 0x06 0xcf 0x38 0x59 0x45 0xb2 0xbe 0xc4 0xea. This value is then base64-encoded, to give the value "s3pPLMBiTxaQ9kYGzzhZRbK+xOo=", which would be returned in the "Sec-WebSocket-Accept" header.

Answer 1

See the crypto.createHash() function and the associated hash.update() and hash.digest() functions:

var crypto = require('crypto')
var shasum = crypto.createHash('sha1')
shasum.update('foo')
shasum.digest('hex') // => "0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33"

Answer 2

Obligatory: SHA1 is broken, you can compute SHA1 collisions for 45,000 USD (and even less since this answer was written). You should use sha256:

var getSHA256ofJSON = function(input){
    return crypto.createHash('sha256').update(JSON.stringify(input)).digest('hex')
}

To answer your question and make a SHA1 hash:

const INSECURE_ALGORITHM = 'sha1'
var getInsecureSHA1ofJSON = function(input){
    return crypto.createHash(INSECURE_ALGORITHM).update(JSON.stringify(input)).digest('hex')
}

Then:

getSHA256ofJSON('whatever')

or

getSHA256ofJSON(['whatever'])

or

getSHA256ofJSON({'this':'too'})

Official node docs on crypto.createHash()

Answer 3

I experienced that NodeJS is hashing the UTF-8 representation of the string. Other languages (like Python, PHP or PERL...) are hashing the byte string.

Tips to get the same hash than Python/PHP,...:

We can add binary argument to use the byte string (this encoding will increase the likelihood of collisions but will be compatible to other languages).

const crypto = require('crypto')

function sha1(data) {
    return crypto.createHash('sha1').update(data, 'binary').digest('hex')
}

text = 'Your text and symbol \xac'

console.log(text, ':', sha1(text))

You can try with : "\xac", "\xd1", "\xb9", "\xe2", "\xbb", "\x93", etc...

Other languages (Python, PHP, ...):

sha1('\xac') //39527c59247a39d18ad48b9947ea738396a3bc47

Nodejs:

sha1 = crypto.createHash('sha1').update('\xac', 'binary').digest('hex') //39527c59247a39d18ad48b9947ea738396a3bc47
//without:
sha1 = crypto.createHash('sha1').update('\xac').digest('hex') //f50eb35d94f1d75480496e54f4b4a472a9148752

Answer 4

You can use:

  const sha1 = require('sha1');
  const crypt = sha1('Text');
  console.log(crypt);

For install:

  sudo npm install -g sha1
  npm install sha1 --save

Answer 5

Please read and strongly consider my advice in the comments of your post. That being said, if you still have a good reason to do this, check out this list of crypto modules for Node. It has modules for dealing with both sha1 and base64.

Answer 6

Answer using the new browser compatible, zero dependency SubtleCrypto API added in Node v15

const crypto = this.crypto || require('crypto').webcrypto;

const sha1sum = async (message) => {
  const encoder = new TextEncoder()
  const data = encoder.encode(message)
  const hashBuffer = await crypto.subtle.digest('SHA-1', data)
  const hashArray = Array.from(new Uint8Array(hashBuffer));                     // convert buffer to byte array
  const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join(''); // convert bytes to hex string
  return hashHex;
}

sha1sum('foo')
  .then(digestHex => console.log(digestHex))

// "0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33"

Node Sandbox: https://runkit.com/hesygolu/61564dbee2ec8600082a884d

Sources:

• https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/digest#converting_a_digest_to_a_hex_string
• https://nodejs.org/api/webcrypto.html#webcrypto_class_subtlecrypto