Node.js crypto.createDiffieHellman(primeLength, generator) Method

The crypto.createDiffieHellman() method is used to create a Diffie-Hellman key exchange object. Also, creates prime of primeLength bits with the help of an optional specific numeric generator. Moreover, if the generator is not defined, then the value 2 is used. 

Syntax:

crypto.createDiffieHellman( primeLength, generator )

Parameters: This method accepts two parameters as mentioned above and described below:

• primeLength: This parameter holds a number of primeLength.
• generator: It can hold a number, string, Buffer, TypedArray, or DataView type of data. Its default value is 2.

Return Value: It returns Diffie-Hellman key exchange object. 

The below examples illustrate the use of crypto.createDiffieHellman() method in Node.js: 

Example 1:

javascript

// Node.js program to demonstrate the
// crypto.createDiffieHellman() method

// Includes crypto module
const crypto = require('crypto');

// Defining prime length
const prime_length = 60;

// Creating DiffieHellman keyexchange object
let diffHell = crypto.createDiffieHellman(prime_length);

// Displays keys which are encoded
console.log(diffHell.generateKeys('base64'));

Output:

CoWIWpiwbCE=

Example 2:

javascript

// Node.js program to demonstrate the
// crypto.createDiffieHellman() method

// Includes crypto module
const crypto = require('crypto');

// Defining prime length and generator
const prime_length = 21;
const generator = 12;

// Creating DiffieHellman keyexchange
// object with all its parameter
let diffHell = crypto.createDiffieHellman(
    prime_length, generator);

// Displays keys which are encoded
console.log(diffHell.generateKeys('hex'));

// Displays public and private keys
console.log("Public Key : ",
    diffHell.getPublicKey('base64'));
console.log("Private Key : ",
    diffHell.getPrivateKey('base64'));

Output:

086501
Public Key :  CGUB
Private Key :  C1rL

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