Node.js crypto.secureHeapUsed() Method

The crypto.secureHeapUsed() method in Node.js is used to get the amount of memory used by the secure heap of the running Node.js process. The secure heap is a section of memory that is reserved for cryptographic operations in the Node.js process. This memory is separate from the main heap, which is used for general-purpose memory allocation in the process.

Syntax:

crypto.secureHeapUsed()

Parameters: This method does not take any parameters

Return Value: This method returns an object indicating the amount of secure memory used by the crypto module, in bytes. 

Steps to use crypto.secureHeapUsed() method:

Step 1: In order to use crypto.secureHeapUsed(), you need to import the crypto module in your Node.js application using the following statement.

const crypto = require('crypto');

Step 2: Perform some cryptographic operations, Let’s generate a random key and compute a hash:

const key = crypto.randomBytes(32);
const hash = crypto.createHash('sha256')
    .update('GeeksForGeeks').digest('hex');

Step 3: Now call the crypto.secureHeapUsed() method to get the amount of memory used by the secure heap:

const bytesUsed = crypto.secureHeapUsed();
console.log(`Heap used by this process: ${bytesUsed} bytes`);

Example 1:

Javascript

const crypto = require('crypto');

// Perform some cryptographic operations
const key = crypto.randomBytes(256);
const hash = crypto.createHash('sha256')
    .update('GeeksForGeeks').digest('hex');

// Get the amount of memory used by the secure heap
const bytesUsed = crypto.secureHeapUsed();

console.log(`Secure heap used: ${bytesUsed.used}`);

Output:

Secure heap used: 16384

Example 2:

Javascript

const crypto = require('crypto');

function generateRandomNumbers(num) {
    const rand = crypto.randomBytes(num);

    // Calculating the secure heap used after
    // doing the cryptographic operation
    console.log(`Bytes used:
        ${crypto.secureHeapUsed().used} bytes`);
}

// Making a function call to
// generate 64 random bytes
generateRandomNumbers(64);

Output:

Bytes used: 12288

The output will be varied depending on the platform and the amount of memory allocated to the secure heap.

Reference: https://nodejs.org/api/crypto.html#cryptosecureheapused