crypto.scrypt() Method in Node.js

The crypto.scrypt() method provides an asynchronous implementation for scrypt method. The scrypt can be defined as a password-based key derivation function that protects the system from the brute-force attacks and makes it unawarding. But the script function is expensive computationally as well as memory-wise.

Syntax

crypto.scrypt(password, salt, keylen, [options], [callback])

Parameters

The above parameters are described as below −

• password – The password field for the scrypt required to decode entry. It can be a string, object, TypedArray, etc.

• salt – This value should be as unique as possible. This is mainly used for encrypting the data. The minimum suggested length of salt is 16 bytes.

• keylen – This parameter defined the length of the key and should be a number.

• options

  • cost – This is the cost of the cpu for each memory taken. This value should be a power of 2 greater than 1. Default value is 16384.

  • blockSize – This parameter defined the value for each block size. Default value is 8.

  • parallelization – This parameter defined the parallelization parameter. Default value is 1.

  • N – This parameter is an alias for cost and can be used in its place. Only one can be defined at a time.

  • r – This parameter is an alias for blockSize and similarly only one can be defined at a time.

  • p – Alias for parallelization. Only one can be defined.

  • maxmem – This is memory upper bound value. An error is thrown when 128*N*r > maxmem. Default value is 32*1024*1024.

• callback – This function is called when an error is thrown if you want to handle it.

Example

Create a file with name – scrypt.js and copy the below code snippet. After creating file, use the following command to run this code as shown in the example below −

node scrypt.js

scrypt.js

// Node.js program to demonstrate the flow of crypto.scrypt() method

// Importing the crypto module
var crypto = require('crypto');

// Calling the scrypt() method with the below parameters
crypto.scrypt('tutorialspoint', 'asdfghjkl', 32, (err, derivedKey) => {

if (err) throw err;

// Prints the derived key as a buffer value
console.log("The derived key(1) is:", derivedKey);
});

// Calling the scrypt() method with the cost option
crypto.scrypt('GeeksforGeeks', 'tfytdx', 128,
   { N: 512 }, (err, derivedKey) => {

if (err) throw err;

// Prints the derived key as a buffer value
console.log("The derived key(2) is:", derivedKey);
console.log();
});

Output

C:\home\node>> node scrypt.js
The derived key(2) is: 

The derived key(1) is: 

Example

Let's take a look at one more example.

// Node.js program to demonstrate the flow of crypto.scrypt() method

// Importing the crypto module
var crypto = require('crypto');

// Initializing the value of salt as a typedArray
const salt = new Uint32Array(7);

// Using the scrypt() method with below parameters
crypto.scrypt('WelcomeTutorialspoint', salt, 16, (err, derivedKey) => {
   if (err) throw err;
   // Printing the derived key in encoded string format
   console.log("The derived key(1) is:",
      derivedKey.toString("ascii"));
});

// Initialising the value of salt as a DataView
const newSalt = new DataView(new ArrayBuffer(5));

// Using the script() method with cost parameter
crypto.scrypt('HelloTutorialspoint', newSalt, 16, { N: 32 }, (err, derivedKey) => {
   if (err) throw err;
   // Printing the derived key in encoded string format
   console.log("The derived key(2) is:",
      derivedKey.toString("base64"));
});

Output

C:\home\node>> node scrypt.js
The derived key(2) is: PBYDRlgayLVGjC8z3YUcSQ==
The derived key(1) is: