canvas-lti/utils/validate.js

A Canvas LTI 1.3 integration tool.

const crypto = require('crypto');
const fs = require('fs');

// Function to load keys from files
function loadKey(file) {
  return fs.readFileSync(file, 'utf8');
}

// Function to extract public key from private key
function extractPublicKeyFromPrivateKey(privateKey) {
    try {
        const privateKeyObject = crypto.createPrivateKey(privateKey);
        const publicKeyObject = crypto.createPublicKey(privateKeyObject);
        return publicKeyObject.export({ type: 'spki', format: 'pem' });
    } catch (error) {
        console.error('Failed to extract public key from private key:', error.message);
        return null; // Or handle the error as appropriate for your application
    }
}

// Function to normalize keys for comparison
const normalizeKey = (key) => key.replace(/\r\n/g, '\n').trim();

// Main function to compare keys
function validateKeys(privateKeyName, publicKeyName) {
  // Load the private and public keys
  const privateKey = loadKey(privateKeyName);
  const publicKey = loadKey(publicKeyName);

  // Extract the public key from the private key
  const extractedPublicKey = extractPublicKeyFromPrivateKey(privateKey);

  // Compare the extracted public key with the provided public key
  return normalizeKey(extractedPublicKey) === normalizeKey(publicKey);
}

// Export the compareKeys function
module.exports = { validateKeys };