Skip to content
Related Articles

Related Articles

Node.js | crypto.createHmac() Method
  • Last Updated : 21 Mar, 2020

The crypto.createHmac() method is used to create an Hmac object that uses the stated ‘algorithm’ and ‘key’.


crypto.createHmac( algorithm, key, options )

Parameters: This method accept three parameters as mentioned avobe and described below:

  • algorithm: It is dependent on the accessible algorithms which are favored by the version of OpenSSL on the platform. It returns string. The examples are sha256, sha512, etc.
  • key: It is the HMAC key which is used to create the cryptographic HMAC hash. It returns string, Buffer, TypedArray, DataView, or KeyObject. And if it is a KeyObject, then its type must be secret.
  • options: It is optional parameter and used to control stream behavior. It returns an object.

Return Type: It returns Hmac object.

Below examples illustrate the use of crypto.createHmac() method in Node.js:

Example 1:

// Node.js program to demonstrate the     
// crypto.createHmac() method
// Includes crypto module
const crypto = require('crypto');
// Defining key
const secret = 'GfG';
// Calling createHmac method
const hash = crypto.createHmac('sha256', secret)
                   // updating data
                   // Encoding to be used
// Displays output



Example 2:

// Node.js program to demonstrate the     
// crypto.createHmac() method
// Defining myfile
const myfile = process.argv[1];
// Includes crypto and  fs module
const crypto = require('crypto');
const fs = require('fs');
// Creating Hmac 
const creathmac = crypto.createHmac('sha1', 'CS-Portal!');
// Creating read stream
const readfile = fs.createReadStream(myfile);
readfile.on('readable', () => {
 // Calling read method to read data
  const data =;
  if (data)
    // Updating
    // Encoding and displaying filename
    console.log("The hmac object returns:"
    `${creathmac.digest('hex')} ${myfile}`);
console.log("Program done!");


Program done!
The hmac object returns: 4605d44703c2620fc2574c9a9216bd3267457324 /run_dir/interp.js


My Personal Notes arrow_drop_up
Recommended Articles
Page :