Node.js diffieHellman.setPublicKey() Method

Last Updated : 11 Aug, 2021

The diffieHellman.setPublicKey() method is an inbuilt application programming interface of class DiffieHellman (dh) within the crypto module which is used to set the public key of dh object.

Syntax:

diffieHellman.setPublicKey(publicKey[, encoding])

Parameters: This method accepts the following two parameters:

publicKey: It is used to denote the private Key.
encoding: It is used to denote the encoding of publicKey. If encoding is provided publicKey expected to be String otherwise Buffer, TypedArray, or DataView.

Example 1:

index.js

// Node.js program to demonstrate the 
// diffieHellman.setPublicKey() Method 
const crypto = require('crypto') 
  
crypto.generateKeyPair('dh', 
    { 
        primeLength: 512, 
        publicKeyEncoding: { 
            type: 'spki', 
            format: 'der'
        }, 
        publicKeyEncoding: { 
            type: 'pkcs8', 
            format: 'der'
        } 
    }, 
    cb 
) 
  
function cb(err, publicKey, publicKey) { 
    // Create Diffie-Hellman instance 
    const dh = crypto.createDiffieHellman(512) 
    // Set the dh's publicKey 
    dh.setPublicKey(publicKey) 
  
    if (publicKey.equals(dh.getPublicKey())) 
        console.log("DH public Key is set successfully") 
}

Run index.js file using the following command

node index.js

Output:

DH public Key is set successfully

Example 2:

index.js

// Node.js program to demonstrate the 
// diffieHellman.setPublicKey() Method 
const crypto = require('crypto') 
  
crypto.generateKeyPair( 
    'dh', 
    { primeLength: 512 }, 
    cb 
) 
  
function cb(err, publicKey, publicKey) { 
    // Export key from KeyObject 
    publicKey = publicKey.export({ type: 'spki', format: 'der' }) 
    // Encode key in base64 
    publicKey = publicKey.toString('base64'); 
    // Create Diffie-Hellman instance 
    const dh = crypto.createDiffieHellman(512) 
    // Set the dh's publicKey 
    dh.setPublicKey(publicKey, 'base64') 
  
    if (publicKey === dh.getPublicKey('base64')) 
        console.log("DH public Key is set successfully") 
}