Node.js hmac.update()用法及代碼示例

// Node.js program to demonstrate the
// crypto hmac.update() method
    
// Importing crypto module
const { createHmac } = require('crypto')
  
// Creating and initializing algorithm and password
const algo = 'sha256'
const secret = 'GFG Secret Key'
  
// Create an HMAC instance
const hmac = createHmac(algo, secret)
  
// Update the internal state of the hmac object
hmac.update('GeeksForGeeks')
  
// Perform the final operations
// Return calculated hash
const result = hmac.digest('base64')
  
// Print the result
console.log(`HMAC hash:${result}`)

// Node.js program to demonstrate the    
// crypto hmac.update() method
  
// Defining myfile
const myfile = process.argv[2];
  
// Includes crypto and fs module
const crypto = require('crypto');
const fs = require('fs');
  
// Creating and initializing algorithm and password
const algo = 'sha256'
const secret = 'GFG Secret Key'
  
// Creating Hmac
const hmac = crypto.createHmac(algo, secret);
  
// Creating read stream
const readfile = fs.createReadStream(myfile);
  
readfile.on('readable', () => {
  
  // Calling read method to read data
  const data = readfile.read();
  
  if (data)
  
    // Updating
    hmac.update(data);
  else {
  
    // Perform the final operations 
    // Return hash value
    const result = hmac.digest('hex')
  
    // Display result
    console.log(`HMAC hash value of ${myfile}:${result}`);
  }
});