Node.js hmac.digest()用法及代碼示例

// Node.js program to demonstrate the
// crypto hmac.digest() 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
// No encoding provided
// Return calculated hmac hash
// value as Buffer
let result = hmac.digest()
  
// Check whether returns value is
// instance of buffer or not
console.log(Buffer.isBuffer(result)) // true
  
// Convert buffer to string
result = result.toString('hex')
  
// Print the result
console.log(`HMAC hash:${result}`)

// Node.js program to demonstrate the    
// crypto hmac.digest() 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 
        // Encoding provided
        // Return hmac hash value
        const result = hmac.digest('base64')
  
        // Display result
        console.log(
    `HMAC hash value of ${myfile}:${result}`);
    }
});